HPV DNA testing of the residual sample of liquid-based Pap test: utility as a quality assurance monitor

Evaluation of human-papillomavirus screening for cervical cancer in China's rural population

Background and Objective

Human papillomavirus (HPV) testing has become a preferred cervical cancer screening. However, most HPV infections are harmless and additional tests are required to screen HPV positive women. The objective of this study is to determine the optimal triage strategies for HPV positive women in China’s rural population.

Methods

A population-based screening was performed at seven rural counties of Jiangxi province, between October 2014 to January 2016. A total of 18,000 women aged 35–64 years were enrolled in this study. The primary screening was performed using CareHPV, HC-2, Cobas ®4,800 or HybriMax. Positive women were further screened with five triage tests: (1) Liquid-based cytology test (LBC); (2) conventional Pap cytology test (Pap smear); (3) HPV16, 18 detection; (4) viral load; and (5) visual inspection with acetic acid and Lugol’s iodine (VIA/VILI). Women who were tested positive were referred for colposcopy. The five triage tests were compared with respect to sensitivity, specificity, referral rate, cost and diagnostic time.

Results

Complete data were available for 17,782 women. The HPV prevalence was 13.6%. Referral rates for colposcopy were 4.5%, 2.8%, 2.8%, 6.6%, and 3.7% with LBC, Pap smear, HPV16/18, viral load, and VIA/VILI, respectively. The sensitivity of the above triage tests was 65.8%, 51.9%, 86.8%, 73.3%, and 41.7%, respectively. The specificity was 69.8%, 81.0%, 85.8%, 52.2% and 65.3%, respectively. The average time to diagnosis was significantly lower with HPV16/18, viral load and VIA/VILI than LBC and Pap smear. In addition, screening cost that leads to identify one HSIL+ woman was the lowest with viral load.

Conclusion

Our data indicate that HPV16/18 and viral load are the optimal triage strategies for HPV screening in China’s rural population.

HPV test result monitoring of different Bethesda categories in gynaecologic cytology: A valuable quality assurance measure

BACKGROUND

High-risk human papillomavirus (HPV) test ordering has evolved since the 2006 ASCCP guidelines. In light of the availability of the HPV test results for most women ≥30 y, regardless of the Pap test diagnosis; we examined their value in assessing the overall performance of cytopathologists (CPs).

METHODS

Data were derived for six CPs for Pap test interpretations over 4 y. HPV positivity rates for atypical squamous cells of undetermined significance (ASC-US) and for patients ≥30 y for negative for intraepithelial lesion or malignancy (NILM) and squamous intraepithelial lesion (SIL) (inclusive of low grade SIL (LSIL), high grade SIL (HSIL), and carcinoma) categories were retrieved for individual CPs. ASC/SIL ratios were analysed overall and separately for patient groups <30 y and ≥30 y. Pearson correlation coefficient was calculated to assess correlation between HPV positivity rates for ASC-US, NILM and SIL, and ASC/SIL ratios.

RESULTS

The overall ASC-US HPV positivity rate was 41%-49% for patients <30 y, 32% for patients ≥30 y. Stratifying by patient age group, ASC-US HPV positivity rate, and ASC/SIL ratio showed a negative correlation. Excluding an outlier, the NILM HPV positivity rate and ASC/SIL ratio showed a strong negative correlation.

CONCLUSION

Our study shows that ASC-US HPV positivity rate is dependent on the age of the population that is tested. Monitoring of the HPV positivity rates for NILM and SIL categories can serve as an additional objective measure to assess the performance of CPs. Based on the patient population, the laboratory can establish an initial baseline for these rates and use it to adjust interpretive thresholds in ensuring the diagnostic sensitivity of the test and the quality of the interpretation.

College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference on good laboratory practices in gynecologic cytology: background, rationale, and organization

CONTEXT

Gynecologic cytopathology is a heavily regulated field, with Clinical Laboratory Improvement Amendments of 1988 mandating the collection of many quality metrics. There is a lack of consensus regarding methods to collect, monitor, and benchmark these data and how these data should be used in a quality assurance program. Furthermore, the introduction of human papilloma virus testing and proficiency testing has provided more data to monitor.

OBJECTIVE

To determine good laboratory practices in quality assurance of gynecologic cytopathology.

DATA SOURCES

Data were collected through a written survey consisting of 98 questions submitted to 1245 Clinical Laboratory Improvement Amendments-licensed or Department of Defense laboratories. There were 541 usable responses. Additional input was sought through a Web posting of results and questions on the College of American Pathologists Web site. Four senior authors who authored the survey and 28 cytopathologists and cytotechnologists were assigned to 5 working groups to analyze data and present statements on good laboratory practices in gynecologic cytopathology at the College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference. Ninety-eight attendees at the College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference discussed and voted on good laboratory practice statements to obtain consensus.

CONCLUSIONS

This paper describes the rationale, background, process, and strengths and limitations of a series of papers that summarize good laboratory practice statements in quality assurance in gynecologic cytopathology.

Implementation of the ThinPrep Imaging System in a tertiary military medical center

BACKGROUND

The ThinPrep Imaging System (TIS) was implemented at Brooke Army Medical Center (BAMC) in February 2006 and has been a crucial part of the ability of the Department of Pathology and Laboratory Services ability to improve efficiency and turnaround times for Papanicolaou (Pap) test reporting. The increased detection rate of squamous abnormalities, specifically high-grade squamous intraepithelial lesions (HSIL), has been well documented by many studies. In addition, the TIS has increased productivity for many laboratories. The objective of this study was to evaluate the effects of implementing the TIS at BAMC, a tertiary military medical center. Specifically, the following were assessed: 1) whether the detection of squamous abnormalities was increased with the TIS, 2) how the rate of high-risk human papillomavirus (HR-HPV) detection in atypical squamous cells (ASC) of undetermined significance (ASC-US) cases changed (or did not change) before and after implementation of the TIS, and 3) how the TIS influenced productivity.

METHODS

All gynecologic cytology at BAMC has been collected and processed using the ThinPrep system since 2002. Before February 2006 and before implementation of the TIS, Pap tests were screened manually by the cytotechnologists. Detection rates of squamous abnormalities were compared between the period from February 2005 to December 2005 (manual screening) and the period from February 2006 to December 2006 (image-assisted screening). Squamous abnormalities included ASC-US; ASC, cannot rule out HSIL (ASC-H); low-grade squamous intraepithelial lesion (LSIL); HSIL; glandular abnormalities; and malignancies (squamous or glandular). In addition, the rates of HR-HPV-positive, HR-HPV-negative, and HR-HPV-quantity not sufficient were compared for the same periods. During both periods, testing for HR-HPV was performed only on ASC-US Pap tests. HR-HPV was tested with Digene Hybrid Capture 2 methodology. Productivity was calculated as the change in average slides screened per hour before and after imager implementation.

RESULTS

In total, 107,647 Pap tests were analyzed in the 2005 (54,438 Pap tests) and 2006 (53,209 Pap tests) timeframes. Increases in the detection of ASC-H, atypical glandular cells (AGC), LSIL, and HSIL were statistically significant. The proportion of negative for intraepithelial lesion or malignancy (NILM) and unsatisfactory cases decreased significantly with implementation of the TIS. The ASC to squamous intraepithelial lesion (ASC:SIL) ratio decreased from 1.5 to 1.0 after TIS implementation. Decreases in the ASC-US HR-HPV-positive proportion and increases in the ASC-US HR-HPV-negative proportion after implementation of the TIS were statistically significant. In our laboratory, a 60% increase in productivity was noted with use of the TIS.

CONCLUSIONS

Implementation of the TIS at BAMC significantly increased the detection of ASC-H, AGC, LSIL, and HSIL but had no significant impact on the ASC-US detection rate. Although the ASC-US rate did not change, both the HR-HPV-positive rate and the ASC:SIL ratio decreased. The data from the current study suggested that, at least initially, the use of imager-directed screening may increase the number of clinically insignificant ASC-US Pap tests.

HPV detection rate in discordant Pap tests between cytotechnologists and pathologists

When a Pap test is referred for pathologist review, it is accompanied by the cytotechnologist's provisional interpretation. Discordant interpretations between pathologists and cytotechnologists are sometimes noted. The objective is to correlate HPV detection rate with both estimated false-negative fraction (EFNF) and ASC to SIL ratio among discordant ASC cases. ThinPrep Pap tests in which the cytotechnologists' provisional interpretations were up- or down-graded by pathologists to ASC were retrieved between January and December 2006. HPV DNA testing was performed using hybrid capture technique. EFNFs and ASC to SIL ratio were estimated for cytotechnologists and pathologists, respectively. Overall, the EFNF ratio was 3.4% and the high-risk HPV DNA detection rates in cases that were "over-" or "under-" interpreted by technologists were 0.71 and 0.40, respectively. The overall ASC to SIL ratio was 1.41 and the high-risk HPV DNA detection rates in cases that were upgraded or downgraded to ASC were 0.40 and 0.71, respectively. In conclusion, our ASC to SIL ratios and EFNF were within acceptable range. We did not observe any association between ASC to SIL ratio and HPV detection rate in cases that were upgraded or downgraded to ASC by pathologists or between EFNF ratio and HPV detection rate in cases that were "over-interpreted" (or "under-interpreted") by cytotechnologists. The HPV detection rates for ASC cases that were originally "over-interpreted" by cytotechnologists were comparable to the HPV detection rates for LSIL, whereas those that were underinterpreted were comparable to the HPV detection rate for ASC.

The value of monitoring human papillomavirus DNA results for Papanicolaou tests diagnosed as atypical squamous cells of undetermined significance: a College of American Pathologists Q-Probes study of 68 institutions

CONTEXT

Papanicolaou (Pap) tests are often diagnosed as atypical squamous cells of undetermined significance (ASC-US). Human papillomavirus (HPV) DNA testing has been proposed as a quality metric for this diagnosis.

OBJECTIVE

To measure the frequency of HPV positivity in Pap tests diagnosed as ASC-US and to examine laboratory variables that are associated with institutional deviation from the mean percent of HPV positivity.

DESIGN

As part of a College of American Pathologist Q-Probes program, 68 participating laboratories retrospectively identified approximately 50 consecutive ASC-US Pap tests that had HPV testing results.

RESULTS

The mean percentage of HPV positivity for ASC-US was 43.74% among institutions surveyed, but it had a broad distribution, with an SD of 17.77%. Associations were found for lower difference of the institutional mean from the surveyed interinstitutional mean percentage of positive HPV with (1) higher numbers of Pap tests in the past year that had HPV testing, (2) in-house HPV testing, and (3) teaching hospitals. All 3 factors correlated with a larger volume of Pap tests per institution. An association was found between patient age and the probability of a positive HPV result, indicating a dependence upon prevalence of HPV.

CONCLUSIONS

Larger volumes of Pap tests may offer an opportunity to gain greater comfort in interpreting Pap tests. While there is significant variability in interinstitutional HPV-positive rates in ASC-US Pap tests, monitoring the HPV-positive rate in ASC-US Pap tests is a valuable broad measure of quality. Performance beyond 2 SDs of the mean should prompt reassessment of diagnostic criteria used in the evaluation of Pap tests and/or investigation of the prevalence of HPV positivity in the population from which the Pap tests are obtained.

Very low human papillomavirus DNA prevalence in mature women with negative computer-imaged liquid-based Pap tests

BACKGROUND

The prevalence of high-risk Human Papillomavirus DNA (hrHPV DNA) in women with negative Papanicolaou (Pap) test results provides a measure of residual risk for cervical neoplasia after cytology screening. The purpose of this study was to document the prevalence of hrHPV DNA in several thousand women ages > or =30 years with negative ThinPrep Imaging System (TIS)-imaged Pap test results in a large academic hospital cytology laboratory.

METHODS

All cytology-negative TIS-imaged ThinPrep Pap tests (TPPT) with hrHPV DNA tests that were performed by the United States Food and Drug Administration (FDA)-approved Hybrid Capture 2 (HC2) method from May 1, 2005 to November 20, 2006 were identified and reviewed. Imaged-negative Pap test slides associated with a positive hrHPV DNA test result were rescreened manually. Variation in hrHPV DNA prevalence was assessed for different age and ethnic groups.

RESULTS

Of 8070 imaged cytology-negative TPPT from women ages 11 to 90 years, hrHPV DNA test results were also available. Among 7426 women ages > or =30 years with a cytology-negative, TIS-imaged, Pap test, a significant age-associated decline in hrHPV DNA prevalence was noted, 3.4% in 3050 women ages 30-45 years, 2.4% in 7426 women ages 30-90 years, and 1.8% in 5491 women ages 40-90 years. The hrHPV DNA-positive rate was 2.3% in 6012 imaged cytology-negative white women and 4.1% in 739 imaged cytology-negative black women.

CONCLUSIONS

Very low HC2 hrHPV DNA rates in 7426 women ages > or =30 years with cytology-negative, TIS-imaged, ThinPrep, Pap tests were similar to recently published data from 1 other academic center and lower than rates reported in previous studies on cytology-negative North American or European women screened manually with conventional or liquid-based Pap tests. These data may impact assessments of how best to combine cytology and HPV testing.

Pap cytopathology and the presence of high-risk human papillomavirus in SurePath™ liquid preservative and Digene cervical sampler specimens

The Digene Hybrid Capture 2 (HC2) assay for high-risk human papillomavirus (HPV) identified 92 (28.7%) infected women by testing 320 SurePath liquid-based Pap samples and a hybrid capture 2 (HC2) sampler collection. HPV positivity was predictive for high-grade lesions. A majority of women had normal cervical readings although 15.8% were HPV-positive. Half of the patients with a reading of atypical squamous cells of undetermined significance (ASCUS) (n=16) were HPV-positive.

The Bethesda Interobserver Reproducibility Study (BIRST): a web-based assessment of the Bethesda 2001 System for classifying cervical cytology

BACKGROUND

The Bethesda System (TBS) along with its companion atlas was updated in 2001 to improve standardization, clarity, and reproducibility of cervical cytology reporting.

METHODS

The authors used a novel web-based format to compare assessments of 77 images demonstrating a range of classical and borderline cytologic changes by a self-selected group of United States cytotechnologists (n = 216) and pathologists (n = 185).

RESULTS

Participants were highly experienced, with 71.2% of cytotechnologists and 53.0% of pathologists reporting >10 years of practice. The mean percentage of exact agreement with the panel was slightly though significantly higher for cytotechnologists (57.0%) compared with pathologists (53.4%), adjusted for experience (P = .004); cervical cytology percentage effort (P = .0005); or cervical accession volume (P = .0002). Compared with the TBS panel, exact agreement was achieved for 55.1% of image ratings compared with 82.3% agreement at the level of Negative vs non-Negative for images with a single-panel interpretation. Agreement with the panel was highest for images classified as Low-Grade Squamous Intraepithelial Lesion and lowest for Atypical Squamous Cells qualified as either of Undetermined Significance or Cannot Exclude a High-Grade Squamous Intraepithelial Lesion. Reviewers were less sensitive in identifying high-grade glandular lesions than they were in identifying high-grade squamous lesions at any threshold (P < .001).

CONCLUSIONS

Morphologic appearances of images were more important determinants than participants' academic or professional degrees with regard to interobserver reproducibility in classifying cervical cytology images. Experienced cytotechnologists and pathologists performed similarly. Participants achieved higher sensitivity for identifying high-grade squamous lesions than they did for high-grade glandular lesions. These findings demonstrated that web-based studies may be useful in assessing interobserver agreement in classifying images.

Age-specific detection of high risk HPV DNA in cytologically normal, computer-imaged ThinPrep Pap samples

OBJECTIVE

Recent cervical cancer screening guidelines for women over age 30 seek to improve the sensitivity of cytology by incorporating high-risk (HR) human papillomavirus (HPV) DNA testing into the screening algorithm, a recommendation based largely on data that utilized the conventional Pap smear and were not stratified by patient age. Data on the rate of HR HPV among women over age 30 undergoing liquid-based Pap test screening are limited. The objective of this study was to determine the rate of HR HPV DNA positivity in women ages 30 and over with a cytologically negative liquid-based Pap test result.

METHODS

Consecutive residual ThinPrep Pap samples from women with a cytologically negative result following computer-assisted screening were tested for HR HPV using the Hybrid Capture 2 (HC2) method. All HC2-positive samples were additionally tested with the Linear Array (LA) HPV Genotyping Test.

RESULTS

1000 cytologically negative specimens from women aged 30 to 45 years (38.9+/-4.7 years) were evaluated. The overall HC2 HR HPV positivity rate in this age group was 3.9% (confidence interval 2.8-5.3%). When stratified by age group, the rate was inversely proportional to age (ages 30-35: 6.7%; 36-40: 3.0%; 41-45: 2.6%) and lower than most previous reports (1-17%). Some of the cases that were positive for HR HPV by HC2 were negative by LA, or showed only low-risk virus.

CONCLUSIONS

The HR HPV rates in women ages 30-45 with a cytologically negative, computer-imaged ThinPrep test result are low. If these findings are confirmed in future studies, the added benefit of HPV testing to liquid-based cytology for women ages 30 and over should be critically evaluated.

Testing automated liquid-based cytology samples with a manual liquid-based cytology method using residual cell suspensions from 500 ThinPrep cases

We report a technical improvement upon a previously disclosed manual liquid-based cytology (MLBC) method; and, we use the improved method to prepare slides from residual ThinPrep specimens in order to see how often ThinPrep diagnoses correspond to diagnoses derived from exhaustive examination of their parent sample suspensions. Residual cell suspensions from 500 ThinPrep cases comprising (1) 20 low-grade squamous intraepithelial lesions (LSILs); (2) 200 high risk (HR) negatives and 20 ASC-US; and (3) 260 screening cytology specimens were studied. Institutional review committee guidelines allowed us to know diagnoses by groups of specimens, but did not allow us to know individual patient diagnoses, so we could not perform case-by-case matched outcome-comparisons. Cells were concentrated by conventional centrifugation and sedimented into a polymer gel that was then vortex-mixed and converted into a viscous cell-rich suspension. The cell suspension was smeared between two clean glass slides, which were air-dried and stained with the Papanicolaou stain. Two study-sets were created, comprising one slide from each case. Each of the two study sets was examined by two cytopathologists, and discordant diagnoses were adjudicated. Because of the ambiguity involved in the "atypical" (ASC-US, ASC-H, AGC) diagnosis categories, only outcomes at the level of LSIL or greater were recorded. All MLBC SILs were digitally imaged and abnormal slides plus digital images were sent to the laboratory that provided the residual automated liquid-based cytology (ALBC) suspensions. The final diagnoses were confirmed by the laboratory that provided the residual ALBC specimens. MLBC slides of the 20 LSIL cases afforded 2 high-grade squamous intraepithelial lesions (HSILs) and 18 LSILs. Those of the 200 HR-Negatives showed 3 HSILs and 30 LSILs; and those of the 20 HR-ASC-US showed 3 HSILs and 9 LSILs. MLBC slides of the 260 screening cytology specimens showed 1 Carcinoma, 3 HSILs and 20 LSILs; affording 3 HSILs and 14 LSILs more than originally diagnosed. The MLBC method of this report is useful for preparing cell suspensions for cytological examination. Our analytical method was exhaustive and used nearly all of the cell material that was provided to us for analysis; therefore, we conclude that this approach is useful for determining how well ALBC instruments represent their parent sample suspensions. It appears that "rare events" may be overlooked when limited sample aliquots are analyzed by ALBC instruments, and this probably accounts for our increased discovery of SILs by the MLBC method. Also, SILs often present as aggregates of cohesive cells which, if overlooked or ineffectively transferred to ALBC slides, would not be diagnosed.

The development of a quality assurance programme for HPV testing within the UK NHS cervical screening LBC/HPV studies

BACKGROUND

Cervical screening by cytology is effective but lacks sensitivity. The addition of human papillomavirus (HPV) testing can improve the effectiveness of screening for early identification of cervical disease. As HPV testing represents a new technology, a quality assurance (QA) programme is necessary to confirm the accuracy of results.

OBJECTIVE

Our main objective was to design a QA programme for use in the English NHS liquid-based cytology (LBC) and HPV Cervical Screening Pilot Study. Our second objective was to use the knowledge gained to design a QA scheme for future general use within cervical screening and HPV testing programmes.

STUDY DESIGN

Four elements were included in the programme: provision of clinical samples of known HPV status for internal quality control (IQC), distribution of panels of unknown samples for external quality assessment (EQA), resubmission of aliquots of samples to the reference laboratory for repeat testing and resubmission to reference laboratory to check for transport problems. Three sites took part in the QA programme using PreservCyt medium and ThinPrep for LBC preparation. The assay used at test sites was HPV hybrid capture (hc2) while the quality assurance laboratory used a combination of hc2, in-house HPV polymerase chain reaction (PCR) tests and HPV linear array (LA).

RESULTS

Four negative, three low positive and 11 positive pools were used in 22 distributions of IQC samples. Seven distributions each of five 'unknown' EQA samples were sent out. Over 400 samples underwent repeat testing. Discrepant samples were further assessed to provide an explanation. Inter- and intra-laboratory consistency was high as measured by Kappa statistics and 96% agreement for EQA samples was obtained.

CONCLUSIONS

The validity of the QA programme was established and reproducibility in different lab settings was reassuring. These results support the use of hc2 as a potential screening test in diagnostic laboratories. The need for robust quality assurance of HPV testing in cervical screening programmes was confirmed and lessons learnt from this pilot study will be incorporated in future schemes.

Human papillomavirus testing as a cytology gold standard: comparing Surinam with the Netherlands

Polymerase chain reaction to detect high-risk human papillomavirus has been suggested as a gold standard for cytology. The Netherlands and Surinam were prospectively compared in regard to the proportions of Negative, Atypical Squamous Cells of Undetermined Significance, and Squamous Intraepithelial Lesion smears that had detectable high-risk human papillomavirus. For the Netherlands, 14 600 negative, 270 Atypical Squamous Cells of Undetermined Significance and 120 Squamous Intraepithelial Lesion smears were evaluated by polymerase chain reaction. For Surinam, 150 negative, 50 Atypical Squamous Cells of Undetermined Significance, and 150 Squamous Intraepithelial Lesion smears were evaluated by polymerase chain reaction. In all, 4% of Dutch and 80% of Surinamese negative smears had detectable high-risk human papillomavirus (chi2=1313, P<0.00001). In total, 41.9% of Dutch and 84% of Surinamese Atypical Squamous Cells of Undetermined Significance smears had detectable high-risk human papillomavirus (chi2=28, P<0.00001). Totally, 67.5% of Dutch and 94% of Surinamese SIL smears had detectable high-risk human papillomavirus (chi2=30, P<0.00001). The Negative: Atypical Squamous Cells of Undetermined Significance odds ratio was 0.058 for the Netherlands and 0.762 for Surinam (chi2homog=31, P<0.00001). The Negative: Squamous Intraepithelial Lesion odds ratio was 0.020 for the Netherlands and 0.255 for Surinam (chi2homog=31, P<0.00001). The Atypical Squamous Cells of Undetermined Significance: Squamous Intraepithelial Lesion odds ratio was 0.347 for the Netherlands and 0.335 for Surinam (chi2homog=0.005, P>0.75). Human papillomavirus DNA testing may not be a suitable gold standard in general because its use would make specificity and sensitivity prevalence-dependent. A new statistic, the percent of Negative pap smears with detectable high-risk human papillomavirus, is posited, which may be important if human papillomavirus DNA testing is used clinically.

Prevalence and typing of HPV DNA by hybrid capture II in women with ASCUS, ASC-H, LSIL, and AGC on ThinPrep Pap tests

Testing for human papillomavirus (HPV) DNA is now a viable option for the management of women with atypical squamous cells of undetermined significance (ASCUS). The utility of reflexive HPV DNA testing for women with a cytologic diagnosis of atypical glandular cells-not otherwise specified (AGC-NOS), ASCUS subtypes, and low-grade squamous intraepithelial lesion (LSIL) has not been well established. In the present investigation, reflex Hybrid Capture II HPV DNA testing results were evaluated for HPV prevalence and type in 371 women with abnormal cytologic diagnoses of ASCUS-not otherwise specified (ASCUS-NOS), ASCUS-suspicious for low-grade squamous intraepithelial lesion (ASCUS-L), atypical squamous cells-cannot exclude high-grade squamous intraepithelial lesion (ASC-H), AGC-NOS, and LSIL on ThinPrep Pap tests. Positive high-risk HPV DNA was identified in 53.6% of the study samples, including ASCUS-NOS 40.2% ASCUS-L 71.4%, ASC-H 37.5%, LSIL 88.6%, and AGC-NOS 0%. We conclude that reflex HPV DNA testing appears to not be useful for colposcopy triage for cytologic diagnoses of LSIL or AGC-NOS.

Resolving ASCUS without recourse to HPV testing: Manual reprocessing of residual automated liquid-based cytology (ALBC) material using manual liquid-based cytology (MLBC)

We show that residual cell material from ThinPrep PapTest (Cytyc Corporation, Boxborough, MA) atypical squamous-cells of undetermined significance (ASCUS) cases may be manually reprocessed to triage women into actionable diagnostic categories (HSIL, LSIL, and Negative). Material remaining from each of 358 ThinPrep ASCUS cases was manually reprocessed as two slides, labeled "A" and "B." Interobserver agreement between case contributors (CCs) and three sequential reviewers (SRs) was analyzed with 186 cases (Study 1), and diagnostic reproducibility between SRs was examined with an additional 172 cases (Study 2). In Study 1, CCs classified 33% of cases as LSIL or greater, SRs classified 60% as LSIL or greater, and there was 58% diagnostic agreement between CCs and SRs. No "Negative" case assignment by one group afforded an "HSIL" assignment by the complementary group. In Study 2, there was 95% agreement between SRs A slide and B slide diagnoses with 54% of A slides and 55% of B slides classified as LISL or greater. Again, no "Negative" case assignment to one slide afforded an "HSIL" assignment to the complementary slide. Overall, 12.6% of the 358 cases showed HSIL, and all HSILs by one observer group were ASCUS or greater by the complementary observer group. Using manual reprocessing beyond the 21-day specimen outdate for HPV testing by the Hybrid Capture II High Risk HPV test (HR-HCII; Digene Corporation, Beltsville, MD), many ThinPrep ASCUS cases were reclassified as LSIL or HSIL. The 12.6% HSIL proportion of this study approximated the 11.5% CIN 2 or greater proportion of the ALTS ASCUS arm. Similar to ALTS, manual liquid-based cytology (MLBC) would have referred nearly 60% of women to colposcopy for a definitive diagnosis of HSIL or LSIL without resorting to HPV testing. These data demonstrate that many cases of automated liquid-based cytology (ALBC)-diagnosed ASCUS represent unrecognized SIL, which is present in the ALBC specimen vial at the time the ASCUS diagnosis is rendered.

Distribution and Prevalence of Human Papillomavirus Genotypes in Routine Pap Smear of 2,470 Korean Women Determined by DNA Chip

Purpose: We examined human papillomavirus (HPV) genotype distribution and prevalence from routine Pap smear cases in Korean women using DNA Chip.

Patients and Methods: A total of 2,470 cervical specimens from women attending routine Pap smear cytology screening in local hospitals was subjected to HPV test. HPV detection and genotyping were done using DNA Chip.

Results: HPV DNA was detected in 44.8% of the patients and in 58.7% of the 861 atypical lesions based on the Bethesda system, including 52.6% of 627 atypical squamous cells of undetermined significance (ASCUS), 69.0% of 168 low-grade squamous intraepithelial lesions (LSIL), and 89.4% of 66 high-grade squamous intraepithelial lesions (HSIL) cases. The most frequently found genotypes in all HPV-positive cases were HPV-16, HPV-52, and HPV-58. HPV-16 was the most prevalent type in within normal limits, ASCUS, and HSIL categories, whereas HPV-51 was most frequently found in LSIL. Multiple infection was identified in about 20% of HPV-positive cases and most of them were that by two different types. HPV-16 was present in the majority of multiple infection cases. A significant decrease in the percentage of multiple infection was observed in HSIL cases compared with ASCUS and LSIL.

Conclusions: The distribution of HPV genotypes in Korean women was revealed to have differences to that of other regions, showing higher frequencies of HPV-52, HPV-58, and HPV-51. HSIL cases were mostly infected by sole HPV-16 whereas LSIL that by various HPV types, suggesting a certain type may become dominant over others as the disease progresses.

Comparison of human papillomavirus genotypes in high-grade squamous intraepithelial lesions and invasive cervical carcinoma: evidence for differences in biologic potential of precursor lesions

High-grade squamous intraepithelial lesions of the cervix are heterogeneous in their invasive potential. Comparison of human papillomavirus types between invasive cervical carcinoma and high-grade squamous dysplasia may provide insight into this biological variability. Liquid-based Pap specimens from 55 high-grade intraepithelial lesions and 47 invasive cervical carcinomas were analyzed by reverse line blot for 27 human papillomavirus types designated high, intermediate, or low risk. Human papillomavirus DNA was present in all high-grade intraepithelial lesions (23 different types) and in 94% (13 types) of invasive carcinomas. High-risk types were present in 81% of invasive carcinomas compared to 58% of high-grade intraepithelial lesions. Severe dysplasias harbored more (79%) high-risk human papillomaviruses as compared to moderate dysplasias (37%). In 40% of high-grade dysplasia cases (59% of moderate dysplasias; 21% of severe) and 13% of invasive carcinomas, intermediate-risk genotypes were identified in the absence of high-risk HPV types. Human papillomavirus 16 was the most common type in all categories, including 47% of high-grade squamous dysplasias (26% moderate; 68% severe) and 61% of invasive carcinomas. Both high-risk type (P=0.0004) and type 16 (P=0.0007) human papillomaviruses were positively associated with increasing severity of diagnosis. The heterogeneous nature of high-grade squamous dysplasias as compared to invasive carcinoma is evident by the wider spectrum of associated human papillomavirus types. Likewise, moderate dysplasia appears to be more heterogeneous in viral type than severe dysplasia. Moderate cases were more often associated with intermediate-risk types, while high-risk types were more prevalent in severe dysplasias and invasive cancers. Moderate dysplasia cases harboring viral types infrequently found in cancers may have a low risk for progression. Human papillomavirus genotyping of high-grade squamous intraepithelial lesions may be important in assessing risk for progression to invasion.

Pap test in a high-risk population comparison of conventional and liquid-base cytology

Liquid-based cytology (LBC) is believed to have better sensitivity than conventional smears (CSs) and offers the possibility to perform molecular assay. The goal of this work was to study the performance of CS and LBC in a high-risk population and to compare the results with the hybrid capture (HC) II for high-risk human papillomavirus (HPV). Samples were collected from selected women with clinical suspicions of low genital tract lesion at Pérola Biygnton Hospital (São Paulo, Brazil). After CS preparation, the brush was introduced in the endocervix and a new sample was collected and rinsed in the preservative medium of the system. The residual material was used to HC2. From 925 cases, LBC was unsatisfactory in 4 (1.51%) cases and CS was unsatisfactory in 100 cases (10.81%); among theses cases HC2(+) reactions was observed in 54 (54%) CSs and 3 (21.4%) LBCs. Considering cases with atypia of undetermined significance (squamous and glandular), 85 (77.27%) cases from LBC and 44 (86.4%) from CS were positive for HC2 assay for high-risk DNA-HPV. The difference among the methods was not significant (P < 0.38). The diagnosis improvement of LBC in comparison with CS was 86% in satisfactory samples, 92.76% in undetermined atypical lesions (including glandular), 83% in positive low-grade squamous intraepithelial lesions (LSIL(+)), and 86.84% in high-grade SIL(+) (HSIL(+)). HC2(+) reactions were observed in 144 CS cases and 266 LBC cases with abnormalities. Our results have showed that LBC was superior to CS in a high-risk population to detect lesions with high concordance with HC2(+) reactions; CSs also exhibit a high concordance with HC2 assay but with inferior performance to detect lesions.

Comparison of Human Papillomavirus DNA Prevalence in Atypical Squamous Cells of Undetermined Significance Subcategories as Defined by the Original Bethesda 1991 and the New Bethesda 2001 Systems

Context.—The new Bethesda System 2001 (TBS 2001) minimized the subclassification of atypical squamous cells of undetermined significance (ASCUS).

Objective.—The primary goal of this study was to determine the impact of the new subclassification on the accuracy of Papanicolaou (Pap) test diagnosis by examining the prevalence of human papillomavirus (HPV) DNA in different ASCUS subcategories, as defined by the new TBS 2001 versus the original TBS 1991. The second goal was to identify specific morphologic features of atypical squamous cells that are more frequently associated with HPV detection.

Design.—Consecutive cases of ThinPrep Pap tests were retrospectively reviewed by a panel of pathologists to obtain consensus diagnoses. The study group consisted of ASCUS cases; the positive control group consisted of low- and high-grade squamous intraepithelial lesions (LSILs and HSILs, respectively); and the negative control group consisted of cases “negative for intraepithelial lesion or malignancy.” All ASCUS cases were subclassified according to TBS 1991 into the following categories: favor reactive (ASCUS-R), favor LSIL (ASCUS-L), favor HSIL (ASCUS-H), and not otherwise specified (ASCUS-NOS). In a separate review, ASCUS cases were subclassified according to TBS 2001 into the following categories: atypical squamous cells of undetermined significance (ASC-US) and atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H). Furthermore, morphologic ASCUS subtypes were recorded (atypical mature, immature, parakeratotic, and atrophic cells); in addition, individual morphologic features of atypical cells were recorded. Broad- spectrum HPV DNA amplification and genotyping was performed using short PCR fragment (SPF 10) polymerase chain reaction/Line Probe assays.

Results.—In cases classified according to TBS 1991, HPV was detected in 32% of negative, 49% of ASCUS, and 93% of LSIL/HSIL cases. On the second review, using the diagnostic categories of TBS 2001, which eliminated the ASCUS-;R category, the number of ASCUS cases decreased by 45%. The prevalence of HPV DNA in ASCUS cases downgraded to the negative category was 38%, which was not significantly different from HPV prevalence in negative cases as diagnosed under TBS 1991. Furthermore, HPV was detected in 56% of ASC-US and 71% of ASC-H cases. The prevalence of HPV in different morphologic subtypes of ASCUS was not significantly different, and none of the 8 individual morphologic features of atypical cells were more frequently associated with HPV detection.

Conclusion.—Elimination of the ASCUS-R category in TBS 2001 resulted in a significant decrease in the number of ASCUS diagnoses. Downgraded cases had a relatively low prevalence of HPV DNA. It is expected that TBS 2001 will increase specificity of the Pap test without compromising its sensitivity.

The ASCUS : SIL ratio and the reference laboratory pathologist

The atypical squamous cells of undetermined significance (ASCUS) : squamous intraepithelial lesion (SIL) ratio was proposed to monitor laboratory use of the ASCUS diagnosis. This study addresses problems associated with comparing pathologists by this means. An intuitive example showed the ASCUS : SIL ratio depends on the prevalence of smears from patients who actually have SIL. In this study of 2000 cervical smears, each of five pathologists made 400 diagnoses. Differences among proportions of SIL diagnoses were statistically significant; differences among proportions of ASCUS diagnoses were not. Had an ASCUS : SIL ratio upper limit of 3.0 been used, two pathologists would have been misidentified as having high ASCUS diagnosis rates. Unlike the situation for laboratories, potential variability in SIL prevalence requires caution in the use of this ratio in assessing pathologists. An alternative measure that is independent of prevalence, the ASCUS : SIL odds ratio, is posited.

Atypical squamous cells: update on current concepts

Besides all the confusion and associated problems that the use of ASC has created, it has initiated substantial investigational interest that has resulted in a better understanding of squamous intraepithelial lesions and the biology of cervical neoplasia. Although the category of ASC has created, and will continue to create, controversy in the diagnostic and management fields, it allows the pathologist to convey uncertainty that may be the result of poor sampling or difficulty in interpretation of a case. It is a valuable tool that the cytopathologist can use to make it known that the Papanicolaou test has its limitations and may need and benefit, in some instances, from support from ancillary studies. Similar limitations are recognized in other areas of pathology and the use of immunohistochemistry or molecular studies is widely accepted as an aid to a more specific and definitive interpretation. The time for the Papanicolaou test to be considered similarly has arrived. HPV DNA testing may not be the perfect test for cervical cancer screening because of high prevalence of HPV infection in the general population; however, it is currently the best-studied ancillary test and has been proven to be cost-effective for the triage of Papanicolaou tests with equivocal squamous cells. It is important for the cytopathologist to have well-developed diagnostic skills in interpreting gynecologic preparations, and to classify cases as ASC only when deemed appropriate. Downgrading cytologic findings that are diagnostic of a squamous intraepithelial lesion to ASC with the hope of supporting it by an HPV test will only result in a devaluation of the Papanicolaou test. Such recourse may, however, be acceptable in specific situations, such as in patients who have complex histories, atypical clinical presentations, or during pregnancy. Quality assurance measures to closely monitor the ASC:SIL ratio and the rate of HPV positivity in ASC cases will be essential to ensure the appropriate use of this interpretive category. The coordination of the 2001 Bethesda and ASCCP consensus meetings resulted in the new subcategories of ASC-US and ASC-H, along with well-defined management strategies for these interpretations. This new and clinically relevant terminology should lead to a reduction in difficulties at the clinical level and a more uniform management of patients, unlike the situation following Bethesda 1991 where the gynecologist was faced with a new "diagnosis" without specific management recommendations. The standardization of reporting and clinical management will also allow more reliable evaluation of patient outcomes and cost analysis. The 2002 American Cancer Society guidelines did not make specific recommendations regarding HPV DNA testing for the triage of patients who have a cytology result of ASC-US [64]. The FDA approved the expanded use of HPV testing in conjunction with the Papanicolaou test for cervical cancer screening in March of 2003. The future is likely to bring additional testing modalities that may be more specific for detecting squamous lesions that are more likely to persist or progress to carcinoma, than the currently available HPV tests. In addition, looking to the more distant future, recently published data from HPV vaccine trials suggests that immunizing women who are negative for HPV-16 may eventually reduce the incidence of cervical cancer [65]. At the present, however, the most effective method to decrease the mortality of this disease process is to make sure that all women have access to, and receive, effective cervical cytologic screening.

Comparison of methods for detection of Chlamydia trachomatis and Neisseria gonorrhoeae using commercially available nucleic acid amplification tests and a liquid pap smear medium

Annual screening for Chlamydia trachomatis infection is currently recommended for sexually active women 15 to 25 years old and for women older than 25 if they have a new or multiple sex partners and have not used condoms during the previous 3 months. Annual screening for cervical abnormalities using the Pap smear has achieved a substantial reduction in morbidity and mortality from cervical cancer. Screening for Neisseria gonorrhoeae infection has likely contributed significantly to the reduction in the rates of gonococcal infection. The introduction of liquid Pap smear methods using exfoliated cervical cells presents an opportunity to screen for these three conditions using one specimen. We evaluated the preservation of C. trachomatis and Neisseria gonorrhoeae DNAs from ThinPrep liquid media (PreservCyt; Cytyc Corp., Boxborough, Mass.); tested the feasibility of using a clinical specimen of this medium for the detection of cytologic abnormalities, C. trachomatis, and N. gonorrhoeae; evaluated the agreement between ligase chain reaction (LCR) performed on PreservCyt and LCR performed on a cervical specimen; and compared the performance of LCR performed on PreservCyt to those of LCR performed on a cervical specimen, culture, PCR performed on a cervical specimen, on urine, and on a vaginal specimen (a multiple-site infection status standard), and transcription-mediated amplification (for C. trachomatis only) from 255 sexually active adolescent women. The agreement between LCR performed on PreservCyt and LCR from a cervical swab in LCx transport medium was high (for C. trachomatis, agreement = 0.97 and kappa = 0.92; for N. gonorrhoeae, agreement = 0.99 and kappa = 0.96). Test performances were similar for LCR-urine, LCR-cervix, and LCR-ThinPrep, with sensitivities from 93 to 99% for C. trachomatis and 81 to 83% for N. gonorrhoeae and specificities from 95.5 to 99% for C. trachomatis and 99.1 to 99.6% for N. gonorrhoeae using a PCR-based multiple-site infection status standard. This is the first study to examine the agreement between liquid cytologic media and multiple nucleic acid amplification tests for the detection of C. trachomatis and N. gonorrhoeae from patient samples. Cytologic fluid shows promise for simultaneous screening for cytologic abnormalities and sexually transmitted infections.

PreservCyt transport medium used for the ThinPrep Pap test is a suitable medium for detection of Chlamydia trachomatis by the COBAS Amplicor CT/NG test: results of a preliminary study and future implications

The commercial COBAS Amplicor CT/NG test (Roche Diagnostic Systems, Meylan, France) is a sensitive and specific method for detection of Chlamydia trachomatis infections. This test currently consists of using a nucleic acid amplification method to detect C. trachomatis in first-void urine specimens and in endocervical swabs collected in 2-sucrose-phosphate (2SP) transport medium. We conducted a prospective study to determine whether the automated COBAS Amplicor CT/NG test can detect C. trachomatis in cervical specimens collected in PreservCyt transport medium (ThinPrep Pap Test; Cytyc Corporation, Boxborough, Mass.). PreservCyt medium is used to preserve cervical samples before the preparation of ThinPrep slides. We collected 1,000 cervical specimens from young women (age range, 15 to 25 years) during routine Pap smear tests. Only specimens with normal cytology and in which the gynecologist found no clinical evidence of urogenital infections were selected. The samples were stored in PreservCyt transport medium at 15 to 20 degrees C. C. trachomatis was detected in 22 of the 1,000 cervical specimens that had been stored in PreservCyt. To confirm the positive samples, the test was repeated on new endocervical swab specimens collected in 2SP transport medium. Only 9 of the 22 positive patients agreed to undergo this control, but all 9 retested positive. To evaluate the influence of storage conditions on the sensitivity of the C. trachomatis PCR test, all of the positive samples were stored at 15 to 20 degrees C in PreservCyt transport medium and were retested every 2 weeks for 6 weeks. C. trachomatis was successfully amplified from all 22 specimens for the whole 6-week period. The prevalence of C. trachomatis infection was 2.2% in our study population. These results demonstrate that PreservCyt transport medium is a suitable transport medium for detection of C. trachomatis by the COBAS Amplicor CT/NG test. The ThinPrep Pap Test may enable gynecologists to monitor for both cervical lesions and C. trachomatis infections with a single endocervical specimen.

Willingness to pay for new Papanicolaou test technologies

The amount of money a woman is willing to pay for liquid-based cytology technology has not been measured. In the present study, 175 women answered a questionnaire asking how much they would pay to decrease their risk of dying of cervical cancer if a new (liquid-based) Papanicolaou (Pap) test was used in place of the conventional smear. When women assumed that the new Pap test reduced the risk of dying of cervical cancer from 1 in 37,000 to 1 in 50,000, the mean amount they were willing to pay was $237. If women had more than 2 children, they were willing to pay more for the new Pap test than women with 2 or fewer children. These data indicate that liquid-based and conventional Pap tests are undervalued and that cost-effectiveness studies generally have not taken into account the preference of women for new Pap test technologies.