Interlaboratory concordance of p16/Ki-67 dual-staining interpretation in HPV-positive women in a screening population

Interobserver agreement in the interpretation of anal cytology

BACKGROUND

Anal cytology represents a tool for anal cancer screening in high-risk populations. In addition to accuracy, the reproducibility of the interpretation is of key importance. The authors evaluated the agreement of anal cytologic interpretation between two cytopathologists.

METHODS

Liquid-based cytologic slides from human immunodeficiency virus (HIV)-negative men who have sex with men (MSM) were evaluated by two readers with at least 10 years of expertise in cervical cytology. Cases with a discordant interpretation were reviewed, and a consensus was reached. Human papillomavirus (HPV) genotyping was performed using a proprietary HPV genotyping test. Unweighted and weighted Cohen kappa and 95% confidence interval (CI) values were calculated.

RESULTS

Overall, 713 slides that were adequate for interpretation were evaluated (MSM: median age, 33 years). An HPV test was performed on 620 samples (87.0%). Considering a dichotomous interpretation (negative for intraepithelial lesion or malignancy vs. atypical squamous cells of undetermined significance or worse), the crude agreement between the two readers was 93.3% (kappa = 0.82; 95% CI, 0.77-0.87). Once a consensus for discordant cases was reached, the best agreement was found for the negative for intraepithelial lesion or malignancy category (511 of 528 samples; 96.8%), whereas the atypical squamous cells of undetermined significance category showed the lowest agreement (90 of 117 samples, 76.9%). Considering the individual cytologic categories, overall agreement was 92.1% (kappa = 0.85; 95% CI, 0.81-0.89). The discordant interpretations were not associated with high-risk HPV infection, HPV16 infection, or MSM age.

CONCLUSIONS

The results indicating excellent interobserver agreement in this study substantiate the use of anal cytology in the setting of human immunodeficiency virus-negative MSM.

Comparison of HPV-positive triage strategies combining extended genotyping with cytology or p16/ki67 dual staining in the Italian NTCC2 study

BACKGROUND

Each high-risk HPV genotype has different oncogenic potential, and the risk of CIN3+ varies according to genotype. We evaluated the performance of different strategies of HPV-positivity triage combining cytology, p16/ki67 dual staining (DS), and extended genotyping.

METHODS

Samples from 3180 consecutive women from the NTCC2 study (NCT01837693) positive for HPV DNA at primary screening, were retrospectively analyzed by the BD Onclarity HPV Assay, which allows extended genotyping. Genotypes were divided into three groups based on the risk of CIN3+. HPV DNA-positive women were followed up for 24 months or to clearance.

FINDINGS

Combining the three groups of genotypes with cytology or DS results we identify a group of women who need immediate colposcopy (PPV for CIN3+ from 7.8 to 20.1%), a group that can be referred to 1-year HPV retesting (PPV in those HPV-positive at retesting from 2.2 to 3.8), and a group with a very low 24-month CIN3+ risk, i.e. 0.4%, composed by women cytology or DS negative and positive for HPV 56/59/66 or 35/39/68 or negative with the Onclarity test, who can be referred to 3-year retesting.

INTERPRETATION

Among the baseline HPV DNA positive/cytology or DS negative women, the extended genotyping allows to stratify for risk of CIN3+, and to identify a group of women with a risk of CIN3+ so low in the next 24 months that they could be referred to a new screening round after 3 years.

FUNDING

Italian Ministry of Health (grant number RF-2009-1536040). Hologic-Genprobe, Roche Diagnostics, and Becton & Dickinson provided financial and non-financial support.

Enhancing Cervical Cancer Screening: Review of p16/Ki-67 Dual Staining as a Promising Triage Strategy

Cervical cancer, primarily caused by high-risk human papillomavirus (HR-HPV) types 16 and 18, is a major global health concern. Persistent HR-HPV infection can progress from reversible precancerous lesions to invasive cervical cancer, which is driven by the oncogenic activity of human papillomavirus (HPV) genes, particularly E6 and E7. Traditional screening methods, including cytology and HPV testing, have limited sensitivity and specificity. This review explores the application of p16/Ki-67 dual-staining cytology for cervical cancer screening. This advanced immunocytochemical method allows for simultaneously detecting p16 and Ki-67 proteins within cervical epithelial cells, offering a more specific approach for triaging HPV-positive women. Dual staining and traditional methods are compared, demonstrating their high sensitivity and negative predictive value but low specificity. The increased sensitivity of dual staining results in higher detection rates of CIN2+ lesions, which is crucial for preventing cervical cancer progression. However, its low specificity may lead to increased false-positive results and unnecessary biopsies. The implications of integrating dual staining into contemporary screening strategies, particularly considering the evolving landscape of HPV vaccination and changes in HPV genotype prevalence, are also discussed. New guidelines and further research are necessary to elucidate the long-term effects of integrating dual staining into screening protocols.

Clinical Performance of Triage Strategies for Hr-HPV-Positive Women; A Longitudinal Evaluation of Cytology, p16/K-67 Dual Stain Cytology, and HPV16/18 Genotyping

BACKGROUND

We evaluated the longitudinal performance of three options: HPV16/18 genotyping (HPV16/18), cytology (LBC), and p16/Ki-67 dual stain cytology (DS) for the triage of high-risk Human Papillomavirus-positive (Hr-HPV+) women within the cervical screening program in Scotland.

METHODS

Data were derived from a cohort of Hr-HPV+ women (n = 385) who participated in PaVDaG (Papillomavirus Dumfries and Galloway) study. Performance of triage strategies for detecting high-grade disease was assessed at 3 (in women <50 years) or 5 years (in women >50 years). Sensitivity, specificity, PPV, and cNPV of each triage test were calculated for CIN2+ and CIN3+ when used singly or sequentially.

RESULTS

The sensitivity of LBC (≥ borderline), DS, and HPV 16/18 genotyping for the detection of CIN2+ was 62.7% (50.7-73.3), 77.7% (63.1-83.7), and 62.7% (50.7-73.3) with corresponding cNPVs of 10.9%, 8.4%, and 11.9%. The option with the highest sensitivity and lowest cNPV was HPV 16/18 genotyping followed by LBC of Hr-HPV other+ and then DS of the LBC negatives. This yielded sensitivity of 94.7% (86.2-98.3) and cNPV 2.7% for CIN2+. Triage performance was similar if women had tested Hr-HPV+ positive by vaginal self-sampling.

CONCLUSIONS

Two-step triage with HPV 16/18 genotyping before LBC (or DS) for Hr-HPV other+ women was associated with a lower risk of significant disease at follow-up compared with single triage approaches.

IMPACT

This study provides longitudinal performance data on triage strategies in Hr-HPV+ women and will be informative for the evolution of cervical screening programs that increasingly rely on molecular technologies.

False Negative Results in Cervical Cancer Screening-Risks, Reasons and Implications for Clinical Practice and Public Health

False negative (FN) results in cervical cancer (CC) screening pose serious risks to women. We present a comprehensive literature review on the risks and reasons of obtaining the FN results of primary CC screening tests and triage methods and discuss their clinical and public health impact and implications. Misinterpretation or true lack of abnormalities on a slide are the reasons of FN results in cytology and p16/Ki-67 dual-staining. For high-risk human papillomavirus (HPV) molecular tests, those include: truly non-HPV-associated tumors, lesions driven by low-risk HPV types, and clearance of HPV genetic material before sampling. Imprecise disease threshold definition lead to FN results in visual inspection with acetic acid. Lesions with a discrete colposcopic appearance are a source of FN in colposcopic procedures. For FAM19A4 and hsa-miR124-2 genes methylation, those may originate from borderline methylation levels. Histological misinterpretation, sampling, and laboratory errors also play a role in all types of CC screening, as well as reproducibility issue, especially in methods based on human-eye evaluation. Primary HPV-based screening combined with high quality-assured immunocytochemical and molecular triage methods seem to be an optimal approach. Colposcopy with histological evaluation remains the gold standard for diagnosis but requires quality protocols and assurance measures.

Performance of HPV E6/E7 mRNA Assay as Primary Screening Test. Results from the NTCC2 Trial

As the primary screening test, E6/E7 mRNA has shown similar sensitivity for CIN3+ and lower positivity rate than the HPV DNA test. Nevertheless, the overall mRNA positivity is too high for immediate colposcopy, making a triage test necessary. The aim was to estimate the mRNA performance as a primary test with different triage strategies. All HPV DNA-positives were tested for mRNA, cytology and p16/ki67. A sample of HPV DNA-negatives were also tested for mRNA to estimate test specificity. We included all CIN3+ histologically diagnosed within 24 months since recruitment. Of the 41127 participants, 7.7% were HPV DNA-positive, of which 66.4% were mRNA-positive. Among the HPV DNA-negatives, 10/1108 (0.9%) were mRNA-positive. Overall, 97 CIN3+ were found. If mRNA was used as the primary test, it would miss about 3% of all CIN3+ with a 22% reduction of positivity compared to HPV DNA. The weighted specificity estimate for <CIN2 was 94.5% (95% CI=93.9%-94.9%) and sensitivity for CIN3+ was 96.9% (95% CI=91.3%-99.1%). If all the weighted estimated 6.0% mRNA-positive women had been referred to colposcopy, PPV for CIN3+ would have been 4.2%. Cytology or p16/ki67 triage would decrease immediate referral to 1.7% and 2.0%, increasing PPV to 11.2% and 11.7%, respectively; total colposcopy referral would be 4.0% and 3.9%, respectively. As the primary screening test, the mRNA assay showed a positivity rate lower than that of HPV DNA, with a small number of CIN3+ missed. Triage with cytology or p16/ki67 would only marginally decrease overall colposcopy referral.

Development of a Nomogram Predicting the Risk of Persistence/Recurrence of Cervical Dysplasia

Background: Cervical dysplasia persistence/recurrence has a great impact on women’s health and quality of life. In this study, we investigated whether a prognostic nomogram may improve risk assessment after primary conization. Methods: This is a retrospective multi-institutional study based on charts of consecutive patients undergoing conization between 1 January 2010 and 31 December 2014. A nomogram assessing the importance of different variables was built. A cohort of patients treated between 1 January 2015 and 30 June 2016 was used to validate the nomogram. Results: A total of 2966 patients undergoing primary conization were analyzed. The median (range) patient age was 40 (18–89) years. At 5-year of follow-up, 6% of patients (175/2966) had developed a persistent/recurrent cervical dysplasia. Median (range) recurrence-free survival was 18 (5–52) months. Diagnosis of CIN3, presence of HR-HPV types, positive endocervical margins, HPV persistence, and the omission of HPV vaccination after conization increased significantly and independently of the risk of developing cervical dysplasia persistence/recurrence. A nomogram weighting the impact of all variables was built with a C-Index of 0.809. A dataset of 549 patients was used to validate the nomogram, with a C-index of 0.809. Conclusions: The present nomogram represents a useful tool for counseling women about their risk of persistence/recurrence after primary conization. HPV vaccination after conization is associated with a reduced risk of CIN2+.

Accuracy of different triage strategies for human papillomavirus positivity in an Italian screening population

How to manage human papillomavirus (HPV)-positive women in cervical cancer screening remains debated. Our study compared different strategies to triage HPV positivity in a large cohort of women participating in a population HPV-based screening program. Women were tested for HPV (Cobas 4800; Roche), and those positive were triaged with cytology; cytology-positives were referred to colposcopy, while negatives were referred to 1-year HPV retesting. All HPV-positive women were also evaluated with p16/ki67 dual staining (Roche). All lesions found within 24 months of follow-up were included in the analyses. Of the 70 146 women tested, 4757 (6.8%) were HPV-positive. Of these, 1090 were cytology-positive and were referred to colposcopy. Of the 2958 HPV-positive/cytology-negative women who presented at 1-year retesting, 1752 (59.9%) still tested positive. Cumulatively, 532 CIN2+ (including 294 CIN3+) were found. The sensitivity of cytology, HPV16/18 and p16/ki67 as triage test for CIN3+ was 67.9%, 56.0% and 85.0%, respectively. The positive predictive value (PPV) for immediate colposcopy referral was 21.0%, 15.8% and 22.9%, respectively. Combining cytology with typing increased sensitivity to 83.9% and lowered PPV to 14.8%, while combining p16/ki67 and typing increased sensitivity to 91.1%, lowering the PPV to 15.9%. Women negative to p16/ki67 triage presented a cumulative 1-year CIN3+ risk of about 1%. In conclusion, when triaging HPV positivity, p16/ki67 performed better than cytology with or without HPV16/18 genotyping. The strategies that included dual staining achieved sensitivity and low 1-year risk for CIN3+ sufficiently high enough to permit considering extending the surveillance interval to 2 to 3 years for HPV-positive/triage-negative women.

Determinants of p16/Ki-67 adequacy and positivity in HPV-positive women from a screening population

BACKGROUND

The objective of this study was to describe the determinants of adequacy and positivity of the p16/Ki-67 assay in a human papillomavirus (HPV)-positive screening population enrolled within the New Technologies for Cervical Cancer 2 (NTCC2) study.

METHODS

ThinPrep slides were immunostained for p16/Ki-67; each slide had 3 reports from different laboratories. The authors included population-related, sampling-related/staining-related, and interpretation-related variables in the analyses. Adequacy and positivity proportions were stratified by variables of interest. Univariate and multivariate logistic models were used to identify determinants of adequacy and positivity.

RESULTS

In total, 3100 consecutive HPV-positive cases were analyzed. Because every slide was interpreted by 3 centers, 9300 reports were obtained, including 905 (9.7%) that were inadequate and 2632 (28.3%) that were positive. The percentage of cases in which all 3 reports were inadequate increased with increasing age of the women and with inadequate cytology. The highest percentage of adequacy in all 3 reports and of cases with all 3 reports positive was observed in specimens from women who had grade ≥2 cervical intraepithelial neoplasia (CIN2+), atypical squamous cells of undetermined significance or more severe (ASC-US+) cytology, or mRNA positivity. The number of inadequate reports was significantly associated with increasing age, inadequate cytology, mRNA negativity, and scant cellularity. A positive p16/Ki-67 report was associated with an ASC-US+ result and with a positive mRNA result in cases both with and without CIN2+ but was associated with an HPV type 16 and/or 18 infection only in CIN2+ cases. The presence of CIN2+ was strongly associated with dual staining positivity.

CONCLUSIONS

The interpretation of p16/Ki-67 results may be influenced by several different variables, all of which are part of the steps in the procedure, and by the characteristics of the screened population.

Implementation of p16/Ki67 dual stain cytology in a Danish routine screening laboratory: Importance of adequate training and experience

Background

Immunocytochemical staining with p16/Ki67 has been suggested as a promising triage biomarker in cervical cancer screening. As dual staining is a subjective method, proper training may be required to ensure safe implementation in routine laboratories and reduce risk of misclassification. We determined concordance between novice evaluators and an expert, stratified by number of slides reviewed at three reading points.

Methods

The study was conducted at the Department of Pathology, Randers, Denmark. Women were eligible if they were aged ≥45, had been enrolled in one of two ongoing clinical studies, and had a dual stain slide available. Dual staining was performed using the CINtec plus assay. Slides were randomly selected from three reading points at which novice evaluators had reviewed <30, ~300, and ≥500 dual stain slides respectively. Level of concordance was estimated using Cohen's Kappa, κ.

Results

Of 600 eligible slides, 50 slides were selected for review as recommended by the manufacturer. Median age was 68 years (range: 58‐74). Overall concordance was good (κ = 0.68, 95% confidence interval [CI]: 0.60‐0.76), with an overall agreement of 84% (95% CI: 70.9%‐92.8%). Concordance improved with increasing number of slides reviewed at a given reading point, from a moderate concordance (κ = 0.47, 95% CI: 0.05‐0.90) after reviewing <30 slides to a good concordance (κ = 0.66, 95% CI: 0.20‐0.88) and a very good concordance (κ = 0.88, 95% CI: 0.66‐1.00) after reviewing ~300 and ≥500 slides, respectively.

Conclusions

When interpreting dual stain slides from older women, concordance increased slightly as novice evaluators received more training and experience. Although further evaluation is warranted, these findings indicate that a significant amount of training and experience of novice evaluators may be needed to ensure accurate dual stain interpretation in this age group. Future studies should accurately describe training and experience of evaluators to enable a better comparison of concordance and diagnostic accuracy across studies.

Trial registration

NCT04114968 and NCT04298957.