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Background
The Pap smear has engendered a tremendous amount of media coverage in recent years. In spite of the emotional and regulatory issues surrounding the test, two facts remain. First, the Pap smear is a screening test. It identifies cells which may indicate a precancerous or cancerous process. However, any abnormal smear must be followed with a careful clinical examination and biopsy. Second, the Pap smear is one of the great success stories in medicine. In fifty years, it has largely helped to reduce the incidence of cervical cancer from one of the leading causes of death in women in the United States to the eighth most common cancer (about 4500 deaths annually). It is estimated that there has been a 75% reduction in cervical cancer deaths since the introduction of the Pap smear. Over 50 million cervical cytologic Pap smears are performed in the United States each year.
An average slide contains 50,000-300,000 cells which the cytotechnologist, who is screening the slide, must review. To make this task even more difficult, there are numerous pre-analytical variables which can make this daunting task even more difficult, such as air-drying, low cellularity, excessive blood and bacteria. It is a tribute to the skill and diagnostic accuracy of these cytotechnologists that the Pap smear has evolved into such an effective screen for cervical cancer.
OUTLINE
There is no test in medicine which is 100% accurate. Even if all the proper collection techniques, specimen handling, and screening procedures are utilized, there will still be a false negative (missed lesion) rate of at least 4%. Up to 2/3 of false negative Pap smear result from factors related to the collection procedure. However, the natural history of cervical dysplasias and carcinomas is such that there is a long time interval (years) from dysplasia to invasive carcinoma. This is why a yearly screening is so important because even if this occurs, the chance of a lesion being missed is very low.
Stephen S. Raab, MD, etal.
Few studies have measured the effect of pre–sign out double viewing of cytology cases as a means to decrease error. Three Agency for Healthcare Research and Quality–funded project sites performed pre–sign out double viewing of 431 pulmonary cytology cases.
Two-step or more differences in diagnosis were arbitrated as interpretive errors, and the effect of double viewing was measured by comparing the frequency of cytologic-histologic correlation–detected errors in the previous 2 years with the double-viewing period. The number of interpretive errors detected by double viewing for the 3 institutions was 2.7%, 0%, and 1.9%, respectively. Double viewing did not lower the frequency of cytologic-histologic correlation false-negative errors.
We conclude that double viewing detects errors in up to 1 of every 37 cases and that biases in the double-viewing process limit error detection.
Quality indices in a cervicovaginal cytology service: before and after laboratory accreditation.
Tan KB, Chang SA, Soh VC, Thamboo TP, Nilsson B, Chan NH.
Department of Pathology, National University of Singapore, National University Hospital, Singapore.
Arch Pathol Lab Med. 2004 Mar;128(3):303-7. Abstract quote
CONTEXT: Quality assurance practices contribute to the effectiveness of cervical screening and are formalized by participation in a laboratory accreditation program.
OBJECTIVE: To identify changes in the quality indices of our cervicovaginal cytology service preceding and following laboratory accreditation by the College of American Pathologists in 2000.
DESIGN: Cervicovaginal cytology quality indices for 2001 (postaccreditation) were compared with those of 1997 (preaccreditation). Performances in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology (PAP) for the years 1999-2002 were analyzed.
RESULTS: A comparison between data for 1997 and 2001 shows the following: (a) a higher inadequacy rate (1.3% vs 0.7%; P <.001) in 2001; (b) maintenance of a low atypical squamous cells of undetermined significance-squamous intraepithelial lesion ratio (0.79 and 0.76, respectively); (c) overall positive predictive values of positive cytology of 82% and 87%, respectively; (d) relatively few changes to the original cytologic diagnoses following review of significant cytohistologic discrepancies (4 cases and 2 cases, respectively); and (e) a higher subsequent positive yield of squamous intraepithelial lesions following atypical squamous cells of undetermined significance diagnoses in 2001 (41% vs 19%; P =.02). The performance of the laboratory and cytotechnologists in the PAP program showed maintenance of a high standard with almost no major discrepancies recorded.
CONCLUSIONS: An increased awareness of quality-related issues and participation in intradepartmental consultation/diagnostic seminars, all part of the accreditation process, have very likely contributed to the modest improvements identified in the cytology service. Future challenges include increases in workload with the anticipated launch of Singapore's national cervical screening program and adaptation to the emerging cervical screening technologies.A practical problem with calculating the false-negative rate of Papanicolaou smear interpretation by rescreening negative cases alone.
Renshaw AA.
Department of Pathology, Baptist Hospital of Miami, Miami, Florida 33176, USA.
Cancer 1999 Dec 25;87(6):351-3 Abstract quote
BACKGROUND: Rescreening negative Papanicolaou (Pap) smears alone is the most commonly employed method of determining the false-negative rate (FNR) or the false-negative proportion for a laboratory. Acceptable FNRs have been proposed, and the number of slides needed to be rescreened to demonstrate a statistically significant difference in FNRs has been determined. The authors sought to determine the range of FNRs this method can measure and, by implication, the value of this method.
METHODS: A literature review and an analysis of the FNRs this method can generate was performed.
RESULTS: If one assumes that the FNR of review is the same as that of initial screening, the maximum measured FNR is only 25%, even with a true FNR of anywhere from 0-100%. In fact, as a laboratory's FNR increases over 50%, the measured FNR decreases back to zero. This range of FNRs corresponds very closely to the published range of FNRs of 1.6-28%. Because many authorities believe that 5% may be the lowest achievable FNR, the entire possible range of measured FNRs is only 5-25%. In this setting, a statistically significant difference of 20% is meaningless, and a statistically significant difference of 10% can only be achieved by laboratories with an initial FNR of less than 15%, and actual changes in FNR that are much greater than 10%.
CONCLUSIONS: FNRs determined by review of negative smears without abnormal smears generate unreliable and potentially seriously misleading results. Current methodologies exist for more accurately determining the FNR of Pap smear screening by incorporating abnormal smears into the review process. There is little justification for further review of negative Pap smears alone as a method for determining the FNR of a laboratory.
Estimating the percentage of Papanicolaou smears that can be reproducibly identified: modeling Papanicolaou smear interpretation based on multiple blinded rescreenings.
Renshaw AA.
Department of Pathology, Baptist Hospital of Miami, Miami, Florida 33176, USA.
Cancer 2001 Aug 25;93(4):241-5 Abstract quote
BACKGROUND: Multiple blinded rescreenings of Papanicolaou (Pap) smears for litigation purposes is based on the assumption that a subset of Pap smears can be reproducibly identified. The size of this subset is not known.
METHODS: To estimate the size of the subset of Pap smears that can be reproducibly identified, a model was constructed based on the results of repeated blinded screenings in the AutoPap Primary Screening System Trial. Additional analysis came from data in the literature.
RESULTS: Routine and AutoPap-assisted screening both have a detection rate for all detected abnormal cases of < 50%. Models with only two subsets or types of slides each with a different detection rate correlated well with the available data. Data from multiple rapid reviews strongly supported the existence of additional definable subsets. Although the percentage of cases with an expected detection rate of 100% in a three-subset model might have been as high as 30% of the abnormal cases detected in a single review, all estimates that included a second subset of slides with at least a 50% detection rate limited the percentage of slides in the 100% sensitive subset of slides to < 2% of all abnormal slides and < 6% of all abnormal slides detected by a single screening.
CONCLUSIONS: Repeated screenings of Pap smears allowed more accurate models of the sensitivity of Pap-smear screening and the overall incidence of abnormal cases. The data strongly supported the existence of multiple subsets of Pap smears, which can be defined by repeated blinded rescreenings. The percentage of slides that can be reproducibly identified was small.
Papanicolaou tests diagnosed as atypical by a cytotechnologist and downgraded to benign by a pathologist: a measure of laboratory quality.Condel JL, Mahood LK, Grzybicki DM, Sturgis CD, Raab SS.
Department of Pathology and Laboratory Medicine, Allegheny General Hospital, Pittsburgh, PA 15212, USA.
Am J Clin Pathol 2002 Apr;117(4):534-40 Abstract quote Follow-up of Papanicolaou (Pap) tests diagnosed as atypical squamous cells of undetermined significance (ASCUS) or atypical glandular cells of undetermined significance (AGUS) by a cytotechnologist and downgraded to benign by a pathologist has not been measured.
Squamous intraepithelial lesion (SIL) follow-up rates were obtained for Pap tests diagnosed as ASCUS (288) or AGUS (94) and downgraded to benign and for Pap tests diagnosed as repair (231). Statistically significant associations were seen between 7 cytotechnologists and between 7 pathologists and ASCUS, AGUS, downgraded ASCUS, and downgraded AGUS rates. The percentage of downgraded ASCUS cases compared with all ASCUS cases per pathologist ranged from 4.8% to 43.7%. Statistically significant associations between pathologists and SIL follow-up rates for downgraded ASCUS diagnoses were seen. The SIL follow-up rate for repair (7.9%) was similar to that for a downgraded ASCUS (11.0%) or AGUS (7.3%).
The parameters of downgraded ASCU and AGUS Pap test interpretations are good quality indicators of individual performance and overall laboratory quality.
Cytohistologic discrepancies: a means to improve pathology practice and patient outcomes.Clary KM, Silverman JF, Liu Y, Sturgis CD, Grzybicki DM, Mahood LK, Raab SS.
Department of Pathology and Laboratory Medicine, Allegheny General Hospital, Pittsburgh, PA 15212, USA.
Am J Clin Pathol 2002 Apr;117(4):567-73 Abstract quote The use of cytohistologic discrepancies to investigate and reduce error seldom is studied.
All gynecologic discrepancies (n = 283; 0.87% and 7.37% of all cytologic and histologic cases, respectively) and nongynecologic discrepancies (n = 146; 2.26% and 0.44% of all cytologic and histologic cases, respectively) for 26 months were classified as sampling or interpretive. Specimen type and pathologist discrepancy percentages, effect of discrepancies on patient outcome, and interobserver agreement of discrepancies were evaluated. Discrepancies were interpretive in 67% and 34% of gynecologic and nongynecologic cases, respectively. Statistically significant associations were seen between individual pathologist and discrepancy percentages. Breast (1.2%) and bronchial (0.8%) cytologic diagnoses had the highest discrepancy percentages. The kappa scores ranged from 0.02 to 0.45 for pairwise agreement of discrepant cases.
Of nongynecologic interpretive discrepancies available for review, 63% (27/43) and 14% (6/43) were of no or minor clinical significance, respectively. Cytohistologic correlation is a useful tool to monitor performance and to identify specimen types prone to error.
The collection procedure actually begins with appropriate instruction of the patient regarding the test. A Pap test should be obtained: Annually after the age of 18 or after the beginning of sexual activity During the second half of the menstrual cycle-i.e., at least two weeks after the start of one menstrual period and before the start of the next menstrual period Without intercourse during the 24 hours prior to the test Without douching during the 24 hours prior to the test
The health care provider is responsible for providing accurate information including:
Patient name
Patient age
Last menstrual period
Pregnancy history
History of hormone use
History of IUD use
Risk factors
Previous abnormal Pap smears
Relevant clinical information-.e.g., abnormal bleeding, discharge, pelvic painThe specific collection procedure utilized will depend on the type of information required or the specific indication for performing the Pap smear. The goal of the actual collection procedure is to produce an adequate, evaluable smear of cellular material from the vagina and/or cervix which can be submitted to the laboratory, along with appropriate clinical information, to be stained and evaluated in accordance with the indication for the test. In
Single-slide Pap smear: an acceptable alternative to the double-slide Pap smear.
Quackenbush SR.
Pathology Interpretation, P.C., Pennsylvania, Ottumwa, IA 52501, USA.
Diagn Cytopathol 1999 May;20(5):317-20 Abstract quote
Pap smears obtained with Ayre spatula and cytobrush by four experienced private practice gynecologists were submitted to the cytology laboratory on either two slides or one slide. For each physician, 500 consecutive cases were studied for each of 4 consecutive years. Compared to the first 2 years (double-slide cases), the rates of abnormal smears increased from 4.28 to 5.58% while the number of unsatisfactory smears decreased from 1.83 to 0.98% for the years with all single-slide cases. These changes were not statistically significant. Follow-up biopsy findings were not different between the groups. Similar findings were seen when the medical community that submits smears to this laboratory began to use primarily a single-slide technique.
The daily screening workload in the laboratory decreased 29% as mostly one-slide smears were submitted despite an increase of 10% in the number of cases. The double-slide method for Pap smears can be safely replaced by a single-slide method.
Adequate numbers of squamous epithelial cells present Evidence that the transformation zone was sampled (i.e., the presence of endocervical cells on the smear) Spread in a relatively even monolayer Epithelial cells not obscured by blood, inflammatory cells, or foreign material such as lubricant or talc appropriately preserved.
Amy L. Adams, MD, etal.
To determine the incidence of clinically significant lesions in long-term follow-up after a diagnosis of inadequate squamous cellularity using former and new criteria, we reviewed conventional Papanicolaou (Pap) smears (January-December 1998) for adequacy based on the Bethesda System 2001 criterion. Of 23,302 Pap smears evaluated in our laboratory, 114 (0.489%) were classified as unsatisfactory and 245 (1.051%) as "satisfactory but limited by" based on the 10% rule. Follow-up information for 5 years was obtained for 172 patients without a concurrent cervical epithelial abnormality: 25 (14.5%) had squamous abnormalities (atypical squamous cells, 22; low-grade squamous intraepithelial lesion, 2; and high-grade squamous intraepithelial lesion, 1).
With the Bethesda System 2001 criterion, 167 (97.1%) of 172 smears had inadequate squamous cellularity and 5 (2.9%) were adequate. No differences in the incidence of squamous abnormalities detected on follow-up were noted between patients with unsatisfactory Pap smears owing to inadequate squamous cellularity and patients with satisfactory and negative smears.
Our findings raise the question whether patients with unsatisfactory Pap smears and a negative history of gynecologic diseases require repeated Pap smears within 2 to 4 months as suggested by the American Society for Colposcopy and Cervical Pathology guideline.Interobserver Variability in Assessing Adequacy of the Squamous Component in Conventional Cervicovaginal Smears
Matthew V. Sheffield, MD,1 Aylin Simsir, MD,2 Lynya Talley, PhD,3 A. Janie Roberson, SCT(ASCP),1 Paul A. Elgert, CT(ASCP)CMIAC,2, and David C. Chhieng, MD
Am J Clin Pathol 2003;119:367-373 Abstract quote
We compared the interobserver reproducibility of estimating the adequacy of the squamous component of conventional Papanicolaou (Pap) smears using traditional and newly proposed criteria. Forty conventional Pap smears with varying degrees of squamous cellularity were reviewed by 13 observers who evaluated adequacy (satisfactory vs unsatisfactory) based on the traditional criterion of estimating 10% slide coverage.After being introduced to the new criterion and the reference images, the observers reevaluated adequacy on the same set of smears, using the new criterion and the reference images. With the original criterion of 10% slide coverage, 15 smears had a unanimous designation; the overall kappa value was 0.49 (P < .001). With the newly proposed adequacy criterion and reference images, 17 smears had a unanimous designation; the overall kappa value was 0.60 (P < .001). The difference in the kappa correlation coefficients was statistically significant (P = .007).
While traditional and newly proposed criteria resulted in fair interobserver agreement, it seemed that the newly proposed criterion, along with the use of reference images, for evaluating adequacy of the squamous component of conventional Pap smears results in better interobserver reproducibility.
Dual Sampling of the Endocervix and Its Impact on AutoCyte Prep Endocervical Adequacy
Sarah J. Day, CT(ASCP)
Eric L. Deszo
and Gregory G. Freund, MDAm J Clin Pathol 2002;118:41-46 Abstract quote
We compared satisfactory for evaluation but limited by (limited by) and unsatisfactory gynecologic cytologic diagnoses for samples collected by conventional smearing with those generated with the AutoCyte Prep in a population with a historic squamous intraepithelial lesion (SIL) rate of less than 1%.Results from 18,819 AutoCyte Preps were compared with 53,835 conventional cervical smears. Furthermore, 23 women ages 18 to 65 years undergoing annual Papanicolaou tests underwent sequential sampling with the AutoCyte Prep and the Surgipath C-E brush. Comparison of the AutoCyte Prep with conventional cytologic diagnoses revealed the following: unsatisfactory rate, down 97%; limited by rate, down 67%; low-grade SIL rate, up 86%; cervical cancer rate, up 300%; and high-grade SIL rate, unchanged. Examination of unsatisfactory and limited by cases for the AutoCyte Prep showed that 88% were due to absence of endocervical cells (ECs). Dual sampling showed no improvement in EC recovery over the AutoCyte collection device. Compared with conventional Papanicolaou smears, the AutoCyte Prep significantly decreased the rate of unsatisfactory and limited by specimens while increasing low-grade SIL and cancer detection and EC recovery.
The majority of limited by specimens with the AutoCyte Prep were due to absence of ECs, but use of a brush-type device for better endocervical sampling did not enhance EC recovery.
ASCCP Patient Management Guidelines*
Pap Test Specimen Adequacy and Quality Indicators
Diane D. Davey, MD, Chair,
R. Marshall Austin, MD, PhD,
George Birdsong, MD
Henry W. Buck, MD,4 J. Thomas Cox, MD
Teresa M. Darragh, MD
Paul A. Elgert, CT(ASCP)
Vivien Hanson, MD
Michael R. Henry, MD
and Jeffrey Waldman, MDAm J Clin Pathol 2002;118:714-718 Abstract quote
Our objective was to provide management guidelines according to Papanicolaou (Pap) test specimen adequacy based on literature review and expert opinion. A task force named by the American Society for Colposcopy and Cervical Pathology (ASCCP) conducted a literature review and discussed appropriate management. The Steering Committee of the ASCCP and other experts reviewed the guidelines.
The guidelines recommend a repeated Pap test in 12 months for most women undergoing routine annual/biennial screening if the current Pap test is negative but either lacks an endocervical/ transformation zone component or is partially obscured. Indications for considering an earlier repeat are also provided.
The preferred management for unsatisfactory Pap tests is a repeated Pap test within a short interval of 2 to 4 months. The management guidelines will help promote optimal and uniform follow-up of women according to Pap test specimen adequacy.Endocervical Status Is Not Predictive of the Incidence of Cervical Cancer in the Years After Negative Smears
Anita B. Bos, MSc,1 Marjolein van Ballegooijen, PhD,1 M. Elske van den Akker-van Marle, MSc,1 Antonius G.J.M. Hanselaar, PhD,2 Gerrit J. van Oortmarssen, PhD,1 and J. Dik F. Habbema, PhD
Am J Clin Pathol 2001;115:851-855 Abstract quote
The clinical relevance of the lack of endocervical cells was never well established in a longitudinal study with histologically proven cervical cancer as an end point.
From the Dutch Network and National Database for Pathology, results for all negative smears obtained in 1990 and 1991 in the Netherlands were retrieved, as were data for all cytologic and histologic examinations performed after the negative smears before April 1998. There were no significant differences between the proportion of preinvasive lesions (cervical intraepithelial neoplasia 1, 2, and 3) detected after negative smears without endocervical cells compared with negative smears with endocervical cells. The proportion of women in whom invasive cancer developed was the same in both groups.
These data suggest there is no reason to advise women with negative smears without endocervical cells to undergo an additional smear.
What Terms Does a Pathologist Use to Diagnose Abnormal Cells on a Pap Smear? (The Bethesda Classification)
For many years, diagnoses of cytological abnormalities was based upon a class system. For example, Class II Pap smears were benign reactive changes. In 1988, a multinational workshop was convened and formulation a new classification system known as the Bethesda Classification. This introduced terms such as ASCUS (Atypical squamous cells of undetermined significance) and LSIL (Low grade squamous intraepithelial lesion). In 1991, this classification was revised. In 2001, a third workshop was held which further refined the classification system. This system acknowledges the introduction of new diagnostic techniques such as thin layer (liquid based) cytology as well as ancillary testing such as DNA probes for HPV. It eliminates the previous category of benign reactive changes, placing it in the category of negative for intraepithelial lesion or malignancy. It also eliminates the term ASCUS and replaces it with ASC (Atypical squamous cells). It further refines these changes as either of undetermined significance or cannot exclude high grade squamous intraepithelial cells.
BETHESDA SYSTEM 2001
CATEGORY DESCRIPTION COMMENTS SPECIMEN TYPE SPECIMEN ADEQUACY GENERAL CATEGORIZATION AUTOMATED REVIEW ANCILLARY TESTING INTERPRETATION/RESULT NEGATIVE FOR INTRAEPITHELIAL LESION OR MALIGNACY When there is no cellular evidence of neoplasia, state this in the General Categorization above and/or in the Interpretation /Result section of the report, whether or not there are organisms or other non-neoplastic findings ORGANISMS Trichomonas vaginalis
Fungal organisms morphologically consistent with Candida spp.
Shift in flora suggestive of bacterial vaginosis
Bacteria morphologically consistent with Actinomyces spp.
Cellular changes consistent with Herpes simplex virusOTHER NON-NEOPLASTIC FINDINGS Optional to report OTHER ENDOMETRIAL CELLS In a woman >/= 40 years
Specify if negative for squamous intraepithelial lesionEPITHELIAL CELL ABNORMALITIES SQUAMOUS CELL Atypical squamous cells of undetermined significance (ASC-US) Atypical squamous cells-cannot exclude HSIL (ASC-H) Low grade squamous intraepithelial lesion (LSIL) Encompassing HPV/mild dysplasia/CIN 1 High grade squamous intraepithelial lesion (HSIL) Encompassing moderate and severe dysplasia, CIS/CIN2 and CIN 3
May add with features suspicious for invasion (if invasion is suspected)Squamous cell carcinoma GLANDULAR CELL Atypical endocervical cells NOS or specify in comments Atypical endometrial cells NOS or specify in comments Atypical glandular cells NOS or specify in comments Atypical endocervical cells, favor neoplastic Atypical glandular cells, favor neoplastic Endocervical adenocarcinoma in situ Adenocarcinoma Endocervical
Endometrial
Extrauterine
Not otherwise specified (NOS)OTHER MALIGNANT NEOPLASMS EDUCATIONAL NOTES AND SUGGESTIONS
- Bethesda 2001 implementation and reporting rates: 2003 practices of participants in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.
Davey DD, Neal MH, Wilbur DC, Colgan TJ, Styer PE, Mody DR.
Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington 40526-0298, USA.
Arch Pathol Lab Med. 2004 Nov;128(11):1224-9. Abstract quote
CONTEXT: The 2001 Bethesda System for the reporting of cervical cytology specimens and the use of new liquid-based and human papillomavirus testing technologies have led to changes in cervical cytology reporting practices.
OBJECTIVES: To analyze current laboratory reporting practices using Bethesda 2001 terminology and to compare results with previous survey data from 1996.
DESIGN: Questionnaire survey mailed to 1751 laboratories in mid-2003.
PARTICIPANTS: Laboratories enrolled in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.
RESULTS: Of the 759 responding laboratories, most (85.5%) had implemented Bethesda 2001 terminology, and the majority had adopted major changes, such as elimination of the benign cellular changes category and the satisfactory but limited category. The median reporting rate for low-grade squamous intraepithelial lesion was 2.1%, compared to a 1996 median rate of 1.6%, but the increase was confined to liquid-based preparations. Reporting rates for high-grade squamous intraepithelial lesion (median, 0.5%) and atypical squamous cells (ASC) had changed little. Most ASC cases were subclassified as "undetermined significance" (median, 3.9%) with ASC, cannot exclude high-grade SIL accounting for a minority (median, 0.2%). The median ratio of ASC to squamous intraepithelial lesions and carcinomas (SIL+) was 1.4 and was lower than the 1996 median ratio of 2.0. Median reporting rates for squamous abnormalities for 2002 were noted to be significantly higher for liquid-based preparations than for conventional smears, while median ASC/SIL+ ratios were lower. Most laboratories offer human papillomavirus testing, but almost half (47%) of laboratories do not know the percentage of positive testing results in patients with ASC. CONCLUSIONS: Most laboratories have implemented Bethesda 2001 terminology. New criteria and liquid-based methods have led to an increase in low-grade squamous intraepithelial lesion reporting rates and a decrease in ASC/ SIL+ ratios when compared with 1996 data. Liquid-based preparations have higher median squamous intraepithelial lesion rates and lower ASC/SIL+ ratios than conventional smears.
What New Techniques Are Available to Assist the Pathologist?
Currently, there are a number of sophisticated tests which have been used as an adjunct to the Pap smear. These adjuvant tests may play a role in triaging Pap smears which are characterized as ASCUS (atypical squamous cells of undetermined significance) and LSIL (low grade squamous intraepithelial lesions). The ASCUS/LSIL Triage Study (ALTS) is a multicenter study comparing different strategies for management. Over 5000 women are enrolled with random assignment to one group receiving colposcopy with repeat Pap test every 6 months, one group with repeat Pap tests every 6 months, and one group receiving a Pap test plus an HPV test. Early reports have indicated that HPV is highly prevalent in women with LSIL, limiting the usefulness of the HPV testing in this population. Others have advocated that HPV negative ASCUS cases should be classified as benign.
One adjuvant test is the second generation Hybrid Capture II (HCII) from Digene (Gaithersburg, MD) utilizes a DNA binding assay. The specimens are obtained from a cervical swab and the material is subjected to a base which disrupts the virus and releases the target DNA. A specific RNA probe is added which binds to the target DNA forming a DNA:RNA hybrid. These hybrids are captured on a solid phase coated with antibodies specific for the DNA:RNA hybrids. These captured hybrids are then detected with antibodies conjugated to alkaline phosphatase which amplifies the signal 3000 fold. The bound alkaline phosphatase is detected by a chemiluminescent dioxetane substrate. When cleaved with alkaline phosphatase, the substrate produces light which is measured. This test is very accurate detecting 89% of high-grade lesions and 100% of cervical cancers in 8,554 women in a high risk population. This test is more sensitive than Pap smears (88.4% vs. 77.7%) but less specific (89.0% vs. 94.2%).
The Cytyc Corporation ThinPrep Pap Test creates a monolayer of cells allowing for greater visualization of cellular detail. The cell imaging device of Tripath's AutoPap uses a neural net computer program that screens the microscopic slide cells using complex algorithms and displaying the abnormal cells for final review by a cytotechnologist. These abnormal cells are then reviewed by a pathologist and a final diagnosis is rendered. This device also combines a monolayer technology to produce a comprehensive package.
LABORATORY TESTS CHARACTERIZATION DIGENE DNA HYBRID CAPTURE
- Characteristics of Apparently False-Negative Digene Hybrid Capture 2 High-Risk HPV DNA Testing.
Jastania R, Geddie WR, Chapman W, Boerner S.
Department of Pathology, University Health Network, and Laboratory Medicine and Pathobiology, the University of Toronto, Toronto, Canada.
Am J Clin Pathol. 2006 Feb;125(2):1-6. Abstact quote
This study characterized cases with a negative high-risk Hybrid Capture 2 (HRHC2; Digene, Gaithersburg, MD) test result with concurrent or follow-up biopsy-confirmed high-grade cervical intraepithelial neoplasia (CIN 2/3). From 2,306 HRHC2 tests, 10 negative results were identified with CIN 2/3 (false-negative rate, 4.5%).
The majority of the patients had abnormal colposcopic findings and high-grade squamous intraepithelial lesion (HSIL) shown by concurrent cytologic examination, although with few abnormal cells. No trend was evident in the location of the dysplastic epithelium or overall lesion size. In 4 tests, the relative light units over cutoff was more than 0.4 but less than 1.0, suggesting that low quantities of human papillomavirus (HPV) DNA were present in the sample.
The negative predictive value for HRHC2 testing may be compromised when the copy number of the HPV DNA is low, and a negative HRHC2 test result may be falsely negative in patients with abnormal colposcopic findings or concurrent cytologic findings showing HSIL.
- A comparison of a prototype PCR assay and hybrid capture 2 for detection of carcinogenic human papillomavirus DNA in women with equivocal or mildly abnormal papanicolaou smears.
Schiffman M, Wheeler CM, Dasgupta A, Solomon D, Castle PE; The ALTS Group.
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892-7234, USA.
Am J Clin Pathol. 2005 Nov;124(5):722-32. Abstract quote
We evaluated Hybrid Capture 2 (HC2) and polymerase chain reaction (PCR) results for paired specimens collected at 19,187 visits from 5,026 of 5,060 women participating in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study (ALTS).
We examined the test agreement between HC2 and PCR detection for any of 13 carcinogenic human papillomavirus types targeted by HC2 and compared clinical performance of the 2 tests for detecting concurrent and follow-up cervical intraepithelial neoplasia (CIN) 3 or cancer. The k value for the 2 assays was 0.65 (95% confidence interval, 0.64-0.66), with 82.7% crude agreement. HC2 was more sensitive (93.6% vs 89.3%; P < .0005) but less specific (41.2% vs 48.5%; P < .0005) than PCR for detecting 2-year cumulative CIN 3 or cancer (n = 503). The presence of multiple types as detected by PCR and/or cytologic abnormality increased the likelihood of an HC2+ result.
Increased sensitivity of HC2 compared with PCR was surprising, given the theoretical advantages of PCR-based methods for analytic sensitivity. Smaller amounts of material used in PCR could have limited its sensitivity, but our results demonstrate the importance of optimization and standardization of PCR-based assays for clinical applications.
- Reproducibility of HPV DNA Testing by Hybrid Capture 2 in a Screening Setting.
Carozzi FM, Del Mistro A, Confortini M, Sani C, Puliti D, Trevisan R, De Marco L, Tos AG, Girlando S, Palma PD, Pellegrini A, Schiboni ML, Crucitti P, Pierotti P, Vignato A, Ronco G.
Center for Study and Prevention of Cancer (CSPO), Florence, Italy.
Am J Clin Pathol. 2005 Nov;124(5):716-21. Abstract quote
Within a large Italian randomized trial on new technologies for cervical cancer screening involving 7 laboratories with different levels of experience, an intralaboratory and interlaboratory quality control program for human papillomavirus (HPV) DNA testing by Hybrid Capture 2 (HC2; Digene, Gaithersburg, MD) was implemented. To monitor the hybridization and detection steps, target samples containing purified, concentration-defined, HPV DNA were introduced in each test run.
Only 3 of 1,024 showed a mistake in a positive vs negative classification with a 1 relative light unit (RLU)/positive control specimen (PC) ratio cutoff. To monitor the preanalytic steps (particularly denaturation), blinded specimens (33 collected in PreservCyt (Cytyc, Boxborough, MA) and 36 in Specimen Transport Medium (STM, Digene) were centrally prepared, divided into aliquots, and sent to each laboratory. The multiple-rater scores for negative (<1 RLU/PC), low-positive (1 to <11 RLU/PC), and high-positive (> or =11 RLU/PC) samples, respectively, were 0.91, 0.60, and 0.69 with PreservCyt and 0.93, 0.87, and 0.90 with STM.
Our data showed high reliability and reproducibility with HC2, with values higher for STM than ThinPrep (Cytyc) samples.
Brian S. Kendall, MD, etal.
Reflex high-risk human papillomavirus (HPV) testing often is used in the management of women with atypical squamous cells of undetermined significance identified in cervicovaginal screening. Following implementation of reflex testing, our laboratory processed 8,022 specimens during a 20-month period; sufficient material was available for testing in 7,334 specimens.
High-risk HPV was detected in 34.10% of these specimens. Detection rates varied with age, with positive rates as high as 58.46% in women 20 years old or younger, decreasing to 14.58% in women older than 35 years. The detection rate, categorized in 5-year age increments, showed a significant decrease until after 35 years, when the rate remained fairly constant (P < .0001). The detection rate decreased over the time of the study.
These results demonstrate that high-risk HPV detection might vary according to the age mix of the population tested and the interval after implementation of testing.
We evaluated the interlaboratory reproducibility of the Hybrid Capture 2 (HC2; Digene, Gaithersburg, MD), a test for oncogenic human papillomavirus (HPV) DNA, using data from 4 clinical center (CC) laboratories and the quality control (QC) laboratory participating in the ASCUS (atypical squamous cells of undetermined significance) and LSIL (low-grade squamous intraepithelial lesion) Triage Study (ALTS).
Residual liquid cytology specimens were tested routinely throughout the duration of ALTS at CC laboratories, and a stratified (by time in the study) random sample of specimens was retested by the HPV QC laboratory using equivalent protocols. Of the specimens selected (N = 1,175, 5.50% of all specimens obtained), 1,072 (91.23%) had sufficient specimen volume for retesting. The k value between all CC laboratories and the HPV QC laboratory was 0.84 (95% confidence interval, 0.78-0.89), with k values for individual CCs and the HPV QC laboratory ranging from 0.79 to 0.89. Agreement between test results was lowest among results for women with negative cytologic findings (0.73); among those with equivocal or abnormal cytologic findings, k values were 0.80 or more.
These data show that HC2 is a reliable test for detecting clinically relevant oncogenic HPV DNA.
Giovanni Negri, MD, Bettina Rigo, Fabio Vittadello, ScD, Eduard Egarter-Vigl, MD, and Christine Mian, ScD
Reproducibility of human papillomavirus (HPV) typing on archived ThinPrep (Cytyc, Boxborough, MA) specimens was evaluated repeating Hybrid Capture II (HCII) (Digene, Gaithersburg, MD) testing after 25 to 40 months (mean, 31.3 months; group 1), 6 to 11 months (mean, 8.4 months; group 2), and 0 to 5 months (mean, 3.5 months; group 3). Another ThinPrep slide was prepared to evaluate cellularity and reproducibility of the cytologic diagnosis.
The mean residual relative light units (RLU) calculated for each group showed a strong decrease of RLU values at the second typing (group 1, 21.69%; group 2, 26.47%; and group 3, 32.25% of original values). No residual HPV DNA was shown in group 1 in 8 (13%) of 60 cases or in groups 2 and 3 in 2 (3%) of 60 cases each. These cases were associated mostly with poor cellularity and reproducibility of the initial cytologic diagnosis in the final cytologic examination. Intergroup statistical analysis of mean relative percentages for cases with satisfactory residual cellularity revealed a significant difference only between groups 1 and 3 (P < .05).
Although mostly reproducible, HPV typing results by HCII on archived specimens are influenced by material consumption. In addition, results might be affected by some DNA degradation after long-term sample storage.
Carol L. Schiller, MD, etal.
The American Society for Colposcopy and Cervical Pathology (ASCCP) has proposed high-risk human papillomavirus (HPV) testing as the "preferred" triage for women with atypical squamous cells of undetermined significance.
We studied 401 atypical squamous cells of undetermined significance liquid-based cervicovaginal cytology split samples for HPV by chromogenic in situ hybridization (CISH) and by Hybrid Capture (HC) II (Digene, Gaithersburg, MD); 202 underwent HC II followed by CISH, and 199 underwent CISH followed by HC II. Of 401 vials, 101 (25.2%) were positive for HPV by 1 or more methods. HC II labeled 83 of 401 (20.7%) samples as positive, while 38 of 401 (9.5%) were positive by CISH. Positive attributes of CISH include the provision of a cytomorphologic link in assessing HPV positivity and comparative ease of use in laboratories without trained molecular diagnosticians. Greater efficacy and quantitative design are advantages of HC II. Comparing data by sequence of testing showed a lower likelihood of positive test results on the second ancillary test than on the first ancillary test, regardless of age or testing method (odds ratio, second/first = 0.58; P = .003).
This finding suggests that liquid-based cervicovaginal cytology samples are not homogeneous throughout. Correlative studies with histology and polymerase chain reaction may clarify predictive values for both methods.
Can human papillomavirus DNA testing substitute for cytology in the detection of high-grade cervical lesions?
Lee KJ, Lee JK, Saw HS.
Department of Obstetrics and Gynecology, College of Medicine, Pochon CHA University, CHA General Hospital, Seoul, Korea.
Arch Pathol Lab Med. 2004 Mar;128(3):298-302. Abstract quote
CONTEXT: High-risk human papillomaviruses (HPVs) are causal factors of cervical carcinomas.
OBJECTIVE: To evaluate the sensitivity and efficiency of HPV DNA testing in comparison with conventional cytology for detection of cervical intraepithelial neoplasia (CIN) and cancer.
DESIGN: Both testing procedures were administered to 593 women, aged 14 to 88 years (average, 41.7 years), who were referred for abnormal cytology from January 2000 through December 2001 at Korea University Guro Hospital (Seoul, Korea). After histologic confirmation by either colposcopically directed biopsy or endocervical curettage, the efficiency of the detection methods for high-grade cervical lesion was evaluated for the following 3 data sets: HPV DNA testing, conventional cytology, and the 2 tests combined.
RESULTS: The sensitivity, specificity, and positive predictive, and negative predictive values for the detection of CIN 2 or higher were 92.4%, 52.4%, 49.3%, and 93.2% for HPV DNA testing; 76.3%, 65.8%, 52.8%, and 84.7% for cytology; and 97.8%, 36.7%, 49.2%, and 97.3% for the combined tests. Among the 151 patients diagnosed with CIN 2 or CIN 3, 137 patients (90.7%) were HPV positive, 116 patients (76.8%) were proven to have abnormal cytology, and 147 patients (97.6%) were positive for either HPV DNA testing or cytology. The sensitivity values for HPV DNA testing and cytology were 97.9% (46/47) and 74.5% (35/47), respectively, for invasive cervical cancer detection, and the combined tests showed 100% (47/47) sensitivity. Depending on the patient's age and the grade of the cervical lesion, HPV DNA testing proved to be significantly more sensitive than cytology for the primary detection of cervical abnormalities (P <.001).
CONCLUSION: Human papillomavirus DNA testing for the detection of high-grade cervical lesions was more sensitive than cytology alone. In addition, the screening sensitivity can be further improved by combining cytology with HPV DNA testing. This approach is especially beneficial in detecting cancer precursors in women older than 60 years.Efficiency of the Hybrid Capture 2 HPV DNA Test in Cervical Cancer Screening A Study by the French Society of Clinical Cytology
Patricia de Cremoux, MD, PhD, Joël Coste, MD, PhD, Xavier Sastre-Garau, MD, PhD, Martine Thioux, Christelle Bouillac, Sylvain Labbé, MD, Isabelle Cartier, MD, Marianne Ziol, MD, Anne Dosda, MD, Catherine Le Galès, PhD, Vincent Molinié, MD, Marie-Cécile Vacher-Lavenu, MD, PhD, Béatrix Cochand-Priollet, MD, PhD, Philippe Vielh, MD, PhD, and Henri Magdelénat, PhD, for the French Society of Clinical Cytology Study GroupAm J Clin Pathol 2003:120;492-499 Abstract quote
The aim of this study was to determine the efficiency of the Hybrid Capture 2 (HC2; Digene, Gaithersburg, MD) human papillomavirus (HPV) assay for the detection of cervical neoplasia. Of the 1,785 patients recruited, 462 (25.88%) were referred for colposcopy owing to previously detected cytologic abnormalities, and 1,323 (74.12%) were voluntary candidates for screening.
For all patients, a Papanicolaou smear and a monolayer smear (ThinPrep, Cytyc, Boxborough, MA) were done. HPV DNA was detected on the residual liquid-based material. False-positive results were observed in 111 cases and comprised 34 cross-reactions (1.90%) and 77 false-positive cases (4.31%) owing to a contiguous strong chemiluminescence signal. Interestingly, all these samples had a relative light units value of 1 to 3 and were contiguous to a sample with a very high HPV DNA load.
The final results showed that high-risk and low-risk HPV DNA were detected in 480 samples (26.89%) and 135 samples (7.56%), respectively. Although HC2 can be considered a reliable and sensitive test for HPV DNA detection, we do not advocate its use for large-scale screening for cervical neoplasia.
Adjunctive human papillomavirus testing in the 2-year follow-up of women with low-grade cervical cytologic abnormalities: a randomized trial and economic evaluation.
Lytwyn A, Sellors JW, Mahony JB, Daya D, Chapman W, Howard M, Roth P, Lorincz AT, Gafni A, Walter SD.
Department of Pathology, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Toronto, Ontario.
Arch Pathol Lab Med. 2003 Sep;127(9):1169-75 Abstract quote.
CONTEXT: Although human papillomavirus (HPV) testing may aid in managing low-grade abnormality on screening cervical cytology, patient compliance with repeat testing programs requires consideration.
OBJECTIVES: To determine effectiveness and costs of repeated Papanicolaou (Pap) test and oncogenic HPV testing for detecting cervical intraepithelial neoplasia 2 or 3.
DESIGN: We conducted a randomized controlled trial of combined Pap test and cervical HPV testing by Hybrid Capture 1 test compared with Pap test alone; tests were performed every 6 months for up to 2 years. The study end point was colposcopic examination performed on all women at 2 years, or earlier if an HPV test was positive or if a Pap test showed high-grade squamous intraepithelial lesion.
SETTING: Sixty-six community family practices.
PARTICIPANTS: Two hundred fifty-seven women with atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion on screening cervical cytology.
MAIN OUTCOME MEASURES: Detection of histologically confirmed cervical intraepithelial neoplasia 2 or 3, fully allocated costs, and loss to follow-up.
RESULTS: Combined Pap test and HPV testing detected 11 (100%) of 11 cases of cervical intraepithelial neoplasia 2/3, whereas Pap test alone detected 7 (63.6%) of these 11 cases (P =.14); corresponding specificities were 39 (46.4%) of 84 and 45 (71.4%) of 63 (P =.005). The cost-effectiveness ratio was Can $4456 per additional case of high-grade cervical intraepithelial neoplasia. Sixty-nine (26.8%) of the 257 women (24.6% combined group vs 29.1% Pap test only group, P =.41) defaulted from testing or from colposcopy when referred with an abnormal result.
CONCLUSIONS: Combined testing was more costly but may detect more cases of cervical intraepithelial neoplasia 2/3 than Pap test alone. However, poor adherence limits usefulness of a management strategy that requires repeated follow-up.Value of human papillomavirus deoxyribonucleic acid testing after conization in the prediction of residual disease in the subsequent hysterectomy specimen.
Lin CT, Tseng CJ, Lai CH, Hsueh S, Huang KG, Huang HJ, Chao A.
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan.
Am J Obstet Gynecol 2001 Apr;184(5):940-5 Abstract quote
OBJECTIVE: Our aim was to evaluate human papillomavirus deoxyribonucleic acid testing after conization in predicting residual disease in the subsequent hysterectomy specimen.
STUDY DESIGN: A prospective study was conducted on 75 patients with grade 3 cervical intraepithelial neoplasia who had cone margins or endocervical curettage specimens showing disease and who elected to undergo hysterectomy after conization. All patients underwent high-risk human papillomavirus deoxyribonucleic acid testing by the Hybrid Capture II (Digene Corporation, Gaithersburg, MD) system before conization and at the time of hysterectomy (within 2-7 weeks after conization). The presence of human papillomavirus deoxyribonucleic acid in cells obtained by endocervical brush before hysterectomy was correlated with residual disease in the hysterectomy specimens.
RESULTS: Of the 92 patients enrolled, 75 were eligible. Of these 75 patients, 52 (69.3%) had persistent human papillomavirus deoxyribonucleic acid after conization, and 27 (36.0%) of the 75 patients had residual cervical neoplasia in the hysterectomy specimens. Those with negative results for human papillomavirus deoxyribonucleic acid after conization were all (23/23) without residual disease in the uterus (100% negative predictive value). All those who had residual disease (27/27) had positive results for human papillomavirus deoxyribonucleic acid at the time of hysterectomy (100% sensitivity). Postconization human papillomavirus deoxyribonucleic acid status (odds ratio, 4.000; 95% confidence interval, 1.531-10.449; P =.005) and grade of dysplasia after endocervical curettage (classified as grade 2 cervical intraepithelial neoplasia or less severe disease vs grade 3 cervical intraepithelial neoplasia: odds ratio, 6.612; 95% confidence interval, 2.837-15.409; P =.0002) were significantly associated with residual tumor in the uterus.
CONCLUSIONS: This prospective study confirms an excellent sensitivity and negative predictive value of human papillomavirus deoxyribonucleic acid testing after conization in predicting residual cervical neoplasia. A strategy of managing patients with grade 3 cervical intraepithelial neoplasia, based on postconization human papillomavirus deoxyribonucleic acid findings and endocervical curettage results, is proposed.
Detection of high-risk subtypes of human papillomavirus in cervical swabs: routine use of the Digene Hybrid Capture assay and polymerase chain reaction analysis.
Brennan MM, Lambkin HA, Sheehan CD, Ryan DD, O'Connor TC, Kealy WF.
Department of Histopathology, Cytology and Gynaecology, Cork University Hospital, Wilton, Cork, Ireland.
Br J Biomed Sci 2001;58(1):24-9 Abstract quote
Human papillomaviruses (HPVs) are major causative agents in the pathogenesis of cervical cancer, and more than twenty types are associated with its development. With the introduction of liquid-based preparation systems, it is envisaged that large-scale HPV testing will be established in the near future. Preliminary studies demonstrate the accessibility of these samples for DNA testing using both the Digene Hybrid Capture assay (DHCA) and polymerase chain reaction (PCR) techniques.
This study aims to assess the validity and sensitivity of the DHCA system to detect high-risk HPV DNA, using two sets of HPV consensus primers (Gp5+/Gp6+ and MY09/MY11) in tandem with routine assessment of cervical smear and biopsy samples.
Results indicate that the combination of DHCA and PCR detects more high-grade lesions than does the DHCA alone. DHCA-negative cases were categorised by subsequent PCR amplification into low-grade HPV-negative (12/16) cervical lesions and high-grade HPV-positive (7/9) cervical lesions. Gp5+/Gp6+ primers were less sensitive in detecting HPV-positive samples than was the MY09/MY11 primer set.
These results support the use of high-risk HPV testing by DHCA, with subsequent analysis of DHCA-negative samples by PCR using the MY09/MY11 primers.
Comparison of human papillomavirus DNA testing and repeat Papanicolaou test in women with low-grade cervical cytologic abnormalities: a randomized trial. HPV Effectiveness in Lowgrade Paps (HELP) Study No. 1 Group.
Lytwyn A, Sellors JW, Mahony JB, Daya D, Chapman W, Ellis N, Roth P, Lorincz AT, Gafni A.
Department of Laboratory Medicine and Pathobiology, University of Toronto, Ont.
CMAJ 2000 Sep 19;163(6):701-7 Abstract quote
BACKGROUND: Results of cervical cytology screening showing atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesions (LSIL) indicate risk for high-grade cervical intraepithelial neoplasia (CIN 2 or 3). In a community-based randomized trial we compared the test performance of human papillomavirus (HPV) DNA testing with that of 6-month repeat Papanicolaou (Pap) test in detecting histologically confirmed CIN 2 or 3.
METHODS: We randomly assigned 212 women aged 16-50 years with ASCUS or LSIL on cervical cytology screening to undergo either immediate HPV DNA testing or a repeat Pap test in 6 months. Cervical swabs for the HPV DNA testing and the Pap smears were obtained by their family physicians. We tested the swabs for oncogenic HPV using the Hybrid Capture II assay (Digene Corp., Beltsville, Md.). Community-based pathologists examined the Pap smears. All women were referred for colposcopy by their family physicians. Two gynecological pathologists assessed the histology findings. We calculated test performance in women who completed the trial using CIN 2 or 3 as the reference standard.
RESULTS: A total of 159 women completed the study. Compared with HPV DNA testing, which detected 87.5% (7/8) of the cases of CIN 2 or 3, repeat Pap smear showing high-grade intraepithelial neoplasia (HSIL) detected 11.1% (1/9) of cases (p = 0.004), and repeat Pap smear showing ASCUS, LSIL or HSIL detected 55.6% (5/9) (p = 0.16). Corresponding specificities were 50.6%, 95.2% (p = 0.002) and 55.6% (p = 0.61). Loss to follow-up was 17.1% in the HPV test group and 32.7% in the repeat Pap group (p = 0.009). Given the 7 cases of CIN 2 or 3 detected by HPV testing and the 5 cases detected by the repeat Pap smear, the incremental cost of HPV testing was calculated to be $3003 per additional case of CIN identified.
INTERPRETATION: HPV DNA testing was more costly but was associated with significantly less loss to follow-up. It may detect more cases of CIN 2 or 3 in women with low-grade cytologic abnormalities.
Benefits and Costs of Using HPV Testing to Screen for Cervical Cancer.Mandelblatt JS, Lawrence WF, Womack SM, Jacobson D, Yi B, Hwang YT, Gold K, Barter J, Shah K.
Lombardi Cancer Center, 2233 Wisconsin Ave NW, Suite 317, Washington, DC 20007.
JAMA 2002 May 8;287(18):2372-81 Abstract quote CONTEXT: Despite quality assurance standards, Papanicolaou (Pap) test characteristics remain less than optimal.
OBJECTIVE: To compare the societal costs and benefits of human papillomavirus (HPV) testing, Pap testing, and their combination to screen for cervical cancer.
DESIGN, SETTING, AND POPULATION: A simulation model of neoplasia natural history was used to estimate the societal costs and quality-adjusted life expectancy associated with 18 different general population screening strategies: Pap plus HPV testing, Pap testing alone, and HPV testing alone every 2 or 3 years among hypothetical longitudinal cohorts of US women beginning at age 20 years and continuing to 65 years, 75 years, or death.
MAIN OUTCOME MEASURE: Discounted costs per quality-adjusted life-year (QALY) saved of each screening strategy.
RESULTS: Maximal savings in lives were achieved by screening every 2 years until death with combined HPV and Pap testing at an incremental cost of $76 183 per QALY compared with Pap testing alone every 2 years. Stopping biennial screening with HPV and Pap testing at age 75 years captures 97.8% of the benefits of lifetime screening at a cost of $70 347 per QALY. Combined biennial HPV and Pap testing to age 65 years captures 86.6% of the benefits achievable by continuing to screen until age 75 years. Human papillomavirus screening alone was equally effective as Pap testing alone at any given screening interval or age of screening cessation but was more costly and therefore was dominated. In sensitivity analyses, HPV testing would be more effective and less costly than Pap testing at a cost threshold of $5 for an HPV test.
CONCLUSIONS: Screening with HPV plus Pap tests every 2 years appears to save additional years of life at reasonable costs compared with Pap testing alone. Applying age limits to screening is a viable option to maintain benefits while reducing costs.
Cost-effectiveness of Alternative Triage Strategies for Atypical Squamous Cells of Undetermined Significance.Kim JJ, Wright TC, Goldie SJ.
Department of Health Policy and Management, Harvard Center for Risk Analysis, 718 Huntington Ave, Second Floor, Boston, MA 02115.
JAMA 2002 May 8;287(18):2382-90 Abstract quote CONTEXT: Every year approximately 2 million US women are diagnosed as having a cervical cytological result of atypical squamous cells of undetermined significance (ASC-US).
OBJECTIVE: To determine the most efficient and cost-effective management strategy for women in the United States diagnosed as having ASC-US.
DESIGN AND SETTING: Cost-effectiveness analysis of data from clinical trials, prospective studies, and other published literature. A computer-based model was used to compare 4 management strategies for a cytological result of ASC-US: immediate colposcopy; human papillomavirus (HPV) triage, which includes colposcopy if high-risk HPV types are detected; repeat cytology, which includes follow-up cytology at 6 and 12 months and referral for colposcopy if a repeat abnormal result occurs; and reclassifying ASC-US as normal in which a cytological result of ASC-US is ignored. Reflex HPV DNA testing uses either residual liquid-based cytological specimens or samples co-collected at the time of the initial screening for conventional cytology. Another method, referred to as the 2-visit HPV DNA triage, requires a woman with an ASC-US result to return within 1 month to provide another speciman sample.
MAIN OUTCOME MEASURES: Years of life saved (YLS), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. RESULTS: The least costly strategy for biennial screening was to reclassify ASC-US as normal, resulting in a reduction in total cancer incidence of 75% for conventional cytology and 84% for liquid-based cytology compared with no screening. The next least costly strategy was HPV DNA testing resulting in a reduction in total cancer incidence of 86% for conventional cytology and 90% for liquid-based cytology, followed by immediate colposcopy with a reduction of 87% and 91%, respectively. Compared with reflex HPV DNA testing, a strategy of repeat cervical cytology or delayed HPV testing costs more but is less effective. When all strategies were compared simultaneously, varying frequency and type of cytological test, biennial (vs every 3 years) liquid-based cytology with reflex HPV testing had a cost of $174 200 per YLS. In a similar comparison, liquid-based cytology with reflex HPV testing conducted every 3 years (vs every 5 years) had a cost of $59 600 per YLS and was more effective and less costly than a strategy of conventional cytology incorporating repeat cytology or immediate colposcopy conducted biennially.
CONCLUSION: Reflex HPV DNA testing provides the same or greater life expectancy benefits and is more cost-effective than other management strategies for women diagnosed as having ASC-US.
The Efficacy of Reprocessing Unsatisfactory Cervicovaginal ThinPrep Specimens With and Without Glacial Acetic Acid
Effect on Hybrid Capture II Human Papillomavirus Testing and Clinical Follow-up
S. Nicholas Agoff, MD,1 Thomas Dean, MD,2 Brigette K. Nixon, MD,1 Kathy Ingalls-Severn, SCT(ASCP),1 Linda Rinker, MT(NCA),1 and Verena S. Grieco, MDAm J Clin Pathol 2002;118:727-732 Abstract quote
We sought to determine the efficacy of remaking initially unsatisfactory cervicovaginal ThinPrep (Cytyc, Boxborough, MA) specimens with and without the addition of glacial acetic acid (GAA) and the effect on human papilloma virus (HPV) Hybrid Capture II (HC2; Digene, Gaithersburg, MD) testing.
A total of 583 initially unsatisfactory ThinPrep slide preparations were identified, and remakes were made with the residual in the PreservCyt (Cytyc) vials with (n = 455) or without (n = 128) GAA. Clinical follow-up information was obtained. The addition of GAA resulted in a 56.5% reduction in unsatisfactory cases, compared with a 26.6% reduction without GAA. Neoplasia and atypia were detected in the reprocessed specimens. The addition of GAA resulted in false-positive HC2 test results in 10 of 10 cases. Neutralization of the specimen may reverse this effect.Reprocessing unsatisfactory ThinPrep specimens with GAA can substantially reduce the overall unsatisfactory rate and result in the detection of significant lesions. However, the addition of GAA can result in false-positive results on HC2 HPV tests.
INFORM HPV
Sharon Davis-Devine, CT(ASCP), etal.
No US Food and Drug Administration–approved method is available to test for human papillomavirus (HPV) DNA in the SurePath liquid-based Papanicolaou (Pap) test (TriPath Care Technologies, Burlington, NC).
We compared the performance characteristics of Inform HPV (Ventana Medical Systems, Tucson, AZ) and Hybrid Capture 2 (HC2; Digene, Gaithersburg, MD) using SurePath for collection. The study included samples from 102 women, aged 18 to 60 years, who underwent a SurePath Pap test immediately before colposcopy and cervical biopsy. Each SurePath specimen was processed additionally for Inform HPV and HC2. Performance characteristics were determined by using the cervical biopsy as the "gold standard." The SurePath, Inform HPV, and HC2 correctly identified high-grade squamous intraepithelial lesions (HSILs) in 15 (94%) of 16, 6 (38%) of 16, and 14 (93%) of 15 cases, respectively.
When only SurePath samples with a diagnosis of atypical glandular and/or squamous cells were examined, Inform HPV and HC2 correctly identified HSIL in 19 (43%) of 44 and 45 (100%) of 45 cases, respectively.
When SurePath is used for collection, Inform HPV lacks sufficient sensitivity to detect HSIL reliably.THIN PREP Use of the Thin Prep Pap Test in clinical practice.
Guidos BJ, Selvaggi SM.
Department of Pathology, Loyola University Medical Center, Maywood, Illinois 60153, USA.
Diagn Cytopathol 1999 Feb;20(2):70-3 Abstract quote
The Thin Prep Pap Test (Cytyc Corp., Boxborough, MA) received approval by the Food and Drug Administration in May 1996 as an alternative to the traditional conventional smear. The present direct-to-vial study assessed the utility of thin-layer technology for cervicovaginal screening in clinical practice.
From May 1997-February 1998 (10 mo), 15,006 cervical smears were processed and evaluated; of these, 5,423 (36.1%) were conventional smears (CS) and 9,583 (63.9%) were Thin Prep slides (TP). Both methods were analyzed to compare specimen adequacy and detection rates of cervical lesions. The TP method reduced the "satisfactory but limited by" rate by 97% and the unsatisfactory rate by 63%. For low-grade squamous intraepithelial lesions (LSILs), TP slides yielded 3.6% (348/9,583) as compared to 0.98% (53/5,423) for CS, an increase of 267%. The TP method detected a threefold increase in the number of high-grade squamous intraepithelial lesions (HSILs) of 1.0% (100/9,583), as compared to 0.3% (17/5,425) for the CS group. The atypical squamous cells of undetermined significance/squamous intraepithelial lesion (ASCUS SIL) ratio was reduced by 54% in the TP group.
In routine usage in our laboratory, the Thin Prep Pap Test yielded a significant increase in the detection of LSILs and HSILs as compared to conventional smears. Specimen adequacy was significantly improved.
The unsatisfactory ThinPrep Pap Test: missed opportunity for disease detection?Bentz JS, Rowe LR, Gopez EV, Marshall CJ.
Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132, USA.
Am J Clin Pathol 2002 Mar;117(3):457-63 Abstract quote Cervical cytology specimens classified as "unsatisfactory for interpretation" represent a potential source of undetected disease.
This prospective study analyzed the potential benefits of a laboratory procedure to reprocess unsatisfactory ThinPrep Pap Tests (Cytyc, Boxborough, MA). All unsatisfactory ThinPrep samples were reprocessed using a glacial acetic acid wash. The study period unsatisfactory rate was compared with that for the previous 12 months.
The initial unsatisfactory rate was 1.3% (197/15,154). Of the unsatisfactory ThinPrep samples, 55.8% (110/197) had residual material for reprocessing. After reprocessing, 67.3% (74/110) were reclassified as "satisfactory" or "satisfactory but limited by," and the final unsatisfactory rate was 0.8% (123/15,154), a 62% decrease. Compared with the previous 12-month rate of 0.9% (209/23,730), this was a 12% reduction.
Seven (6.4%) of 110 initially classified as unsatisfactory contained an epithelial abnormality (atypical squamous cells of undetermined significance, 3; atypical glandular cells of undetermined significance, 2; low-grade squamous intraepithelial lesion, 1; squamous cell carcinoma, 1) on the reprocessed slide.
Reprocessing of unsatisfactory ThinPrep slides yielded additional cellular abnormalities that otherwise would have been undetected. The present study confirms that reprocessing of unsatisfactory ThinPrep slides is a beneficial laboratory procedure
AUTOPAP (SUREPATH) The AutoPap 300 QC System multicenter clinical trials for use in quality control rescreening of cervical smears: I. A prospective intended use study.
Patten SF Jr, Lee JS, Wilbur DC, Bonfiglio TA, Colgan TJ, Richart RM, Cramer H, Moinuddin S.
NeoPath Inc., Redmond, Washington, USA.
Cancer 1997 Dec 25;81(6):337-42 Abstract quote
BACKGROUND: The AutoPap 300 QC System is an automated device for the analysis of conventionally prepared cervical cytology slides. The AutoPap System selects an enriched population of cases for human quality control (QC) review. The device assigns a score based on the likelihood that a slide is abnormal. Cases are selected for QC rescreening that have scores exceeding a preset threshold corresponding to approximately the top 10% (or greater) of scores.
METHODS: AutoPap false-negative detection, compared with a 10% random QC process, was tested in a 6-center clinical evaluation study. At each site, a block of up to 150 consecutive negative slides (including detected false-negative cases) were selected randomly daily. All slides were run on the AutoPap System and rescreened by cytotechnologists for truth determination. The false-negative cases included in the top 10% group selected by AutoPap System then were compared with false-negative detection by the random selection process.
RESULTS: Fourteen thousand nine hundred fourteen cases were analyzed. The AutoPap-enriched 10% quality control group contained false-negative cases at rates 3 to 5 times that of the random selection method (P < 0.01). The sensitivity for all false-negative cases was 35% and was 52% for false-negative cases at the level of low grade squamous intraepithelial lesion and higher.
CONCLUSIONS: The AutoPap 300 QC System provides the potential for a marked increase in the number of false-negative cervical cytology cases that can be detected on QC rescreening. A significant reduction in laboratory false-negative rates can be expected if this device is utilized in routine practice.
The AutoPap 300 QC System multicenter clinical trials for use in quality control rescreening of cervical smears: II. Prospective and archival sensitivity studies.
Patten SF Jr, Lee JS, Wilbur DC, Bonfiglio TA, Colgan TJ, Richart RM, Cramer H, Moinuddin S.
NeoPath, Inc., Redmond, Washington, USA.
Cancer 1997 Dec 25;81(6):343-7 Abstract quote
BACKGROUND: The AutoPap 300 QC System is an automated device for the analysis of conventional cervical cytology slides. The AutoPap selects an enriched population of cases for quality control review. These studies evaluated the overall sensitivity of AutoPap device to a wider variety of cytologic abnormalities than could be analyzed in the prospective portion of the clinical trials.
METHODS: At five clinical trial sites, positive cases were selected from: 1) archives (historic sensitivity study) or 2) current positive cases (current archive sensitivity study). Cases were analyzed by the AutoPap System along with matched negative cases and stratified into detection deciles by instrument score for each diagnostic category.
RESULTS: For the historic sensitivity study, the percentages of cases present within the top 10% instrument scores were as follows: atypical glandular cells of undetermined significance (AGUS): 33.7% (n = 243); low grade squamous intraepithelial lesion (LSIL): 57% (n = 412); high grade squamous intraepithelial lesion (HSIL): 81.6% (n = 385); and carcinoma: 77.7% (n = 139). For the current archive sensitivity study, the percentage of cases within the top 10% of instrument scores were as follows: atypical squamous cells of undetermined significance (ASCUS): 37.6% (n = 205); AGUS: 27.3% (n = 22); LSIL: 53.7% (n = 410); HSIL: 80.7% (n = 202); and carcinoma: 62.5% (n = 8). Sensitivities at higher percentiles proportionately were greater.
CONCLUSIONS: The AutoPap 300 QC System is detection sensitive, particularly at the level of LSIL and greater. When coupled with the data from the prospective intended use study, these results provided confirmation of the instrument's ability to enhance the false-negative detection rate significantly when compared with a 10% random case selection process. In addition, high sensitivities to all categories of abnormality suggest the possibility of using such instrumentation as a primary screening device for cervical cytology.
Does use of the AutoPap assisted primary screener improve cytologic diagnosis?
Bibbo M, Hawthorne C, Zimmerman B.
Department of Pathology and Cell Biology, Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
Acta Cytol 1999 Jan-Feb;43(1):23-6 Abstract quote
OBJECTIVE: To correlate the ranked review slides by the AutoPap Assisted Primary Screener with the final cytologic diagnosis and to assess whether the ranking of slides improves diagnostic accuracy.
STUDY DESIGN: A total of 5,865 consecutive conventional and suitable cervical/vaginal smears, including high-risk (HR) cases, were processed by the AutoPap System. All slides designated Review were manually screened by two cytotechnologists using the Ranked Review Report. All abnormal findings and reactive/reparative changes were referred to two attending cytopathologists for a final diagnosis. After screening, the Review slides called Within Normal Limits (WNL) were selected according to rank for a further Quality Control (QC) review by the supervisor. All HR cases not selected by AutoPap for QC review were also rescreened. The final diagnoses of the possibly abnormal/reactive/reparative referred slides were recorded and distributed in five ranks according to the Ranked Review Report assignment.
RESULTS: Of 5,865 slides, 5,120 (87%) qualified for scanning. The AutoPap System designated 3,840 (75%) slides for manual review. One thousand three hundred forty-five slides were assigned for QC review. After elimination of nonqualified slides, 763 remained. Rescreening detected 1 high grade squamous intraepithelial lesion (HSIL), 2 low grade squamous intraepithelial lesions (LSIL), 5 atypical squamous cells of undetermined significance (ASCUS) and 5 Benign Reactive Changes (BRC). QC of 364 HR cases revealed 1 LSIL, 2 ASCUS and 3 BRC. Ultimately, 313 (8.1%) smears were diagnosed as ASCUS or a more severe abnormality, 262 (6.8%) as reactive/reparative changes, 3,259 (84.8%) as WNL and 6 (0.1%) as unsatisfactory. Of 313 abnormal slides, 181 were ranked by the system in the 1st rank, 61 in the 2nd, 38 in the 3rd, 19 in the 4th and 14 in the 5th. No HSIL or more severe lesions occurred in the fourth and fifth ranks.
CONCLUSION: Our study validated the claim by the manufacturer that a significant epithelial abnormality is more likely to be present if a high score is assigned to a slide. The preliminary results support use of the AutoPap Assisted Primary Screener to improve cytologic diagnosis.
Sensitivity studies of AutoPap System Location-Guided Screening of cervical-vaginal cytologic smears.
Huang TW, Lin TS, Lee JS.
Taipei Institute of Pathology, Taiwan, Republic of China.
Acta Cytol 1999 May-Jun;43(3):363-8 Abstract quote
OBJECTIVE: To present the results of a study that assessed the efficacy of a cervical cytology screening method utilizing the AutoPap System with Location-Guided Screening (AutoPap LGS) software for detecting abnormal Papanicolaou smear slides.
STUDY DESIGN: Two hundred cases of abnormal cervical and vaginal smears were selected from the recent archives of the Taipei Institute of Pathology. For each abnormal slide, a matched "within normal l