Improved abnormal Pap smear triage using cervical cancer biomarkers

Principles of Analytic Validation of Immunohistochemical Assays: Guideline Update

CONTEXT.—

In 2014, the College of American Pathologists developed an evidence-based guideline to address analytic validation of immunohistochemical assays. Fourteen recommendations were offered. Per the National Academy of Medicine standards for developing trustworthy guidelines, guidelines should be updated when new evidence suggests modifications.

OBJECTIVE.—

To assess evidence published since the release of the original guideline and develop updated evidence-based recommendations.

DESIGN.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and update the original guideline recommendations using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS.—

Two strong recommendations, 1 conditional recommendation, and 12 good practice statements are offered in this updated guideline. They address analytic validation or verification of predictive and nonpredictive assays, and recommended revalidation procedures following changes in assay conditions.

CONCLUSIONS.—

While many of the original guideline statements remain similar, new recommendations address analytic validation of assays with distinct scoring systems, such as programmed death receptor-1 and analytic verification of US Food and Drug Administration approved/cleared assays; more specific guidance is offered for validating immunohistochemistry performed on cytology specimens.

P16/Ki67 Dual Staining in Glandular Cell Abnormalities of the Uterine Cervix

Very limited information exists about the role of p16/Ki67 dual staining on glandular cells in detecting glandular precancerous lesions and cervical adenocarcinoma. In this study, we investigated the diagnostic accuracy of p16/Ki67 dual staining for the detection of glandular and squamous lesions on the uterine cervix and for cancer of the upper reproductive tract. We performed a retrospective analysis of prospectively collected data on 96 patients with glandular cell abnormalities. We analyzed the diagnostic accuracy of p16/Ki67 dual staining for atypical glandular cells, not otherwise specified (AGC-NOS); atypical glandular cells, favor neoplastic (AGC-FN); adenocarcinoma in situ (AIS); and A-CA (cervical adenocarcinoma). A separate analysis for the detection of squamous precancerous lesions and squamous-cell carcinoma (CIN3+) and for cancer of the upper reproductive tract (EC/OC) was performed. Among patients who had normal histology or a low-grade lesion on final analysis, only 8.5% had positive dual staining. On the other hand, 85.7% of patients with AIS+ on final histology had positive dual staining. The respective specificities of p16/Ki67 dual staining on AGC-NOS for the detection of AIS+ (adenocarcinoma in situ or cervical adenocarcinoma), CIN3+ and EC/OC were 91.5%, 88.7% and 86.4%. High specificity values of p16/Ki67 dual staining on cervical smears labelled as AGC-NOS for the detection of CIN3+ and AIS+ suggest that this method might be a useful addition in cervical cancer screening.

p16/Ki67 dual stain triage versus cytology in primary human papillomavirus-based cervical cancer screening with limited genotyping

The introduction of primary human papillomavirus (HPV) cervical cancer screening requires the implementation of an appropriate triage strategy that will be effective in detecting high-grade cervical disease without losing diagnostic specificity. From the 30.066 screening tests results, a total of 1086 with available high-risk human papillomavirus (HRHPV) with limited genotyping, cytology, and p16/Ki67 dual-stain were selected. Two triage strategies for primary HPV screening were analyzed retrospectively based on the study group. Performance characteristics for p16/Ki67 and cytology triage in the detection of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and grade 3 or worse (CIN3+) were calculated, detected in colposcopic biopsy. In HPV16/18-positive cases, primary HPV with p16/Ki67 triage was significantly more specific than cytology (53.1%/16.8% for CIN2+; p < 0.0001; 45.9%/17.0% for CIN3+; p < 0.0001), with yielded sensitivity (95.7%/84.8% for CIN2+; p = 0.0955; 100.0%/87.5% for CIN3+; p = 0.0832). In other HRHPV-positive cases (N16/N18), p16/Ki67 triage was also significantly higher specific (51.3%/15.3% for CIN2+; p < 0.0001; 44.5%/16.5% for CIN3+; p < 0.0001), with sensitivity (92.3%/74.4% for CIN2+; p = 0.0522; 90.9%/81.8% for CIN3+; p = 0.5637). Diagnostic predictive values were significantly higher for p16/Ki67 triage with the highest PPV in HPV16/18-positive cases for CIN2+ (45.4%; 95% confidence interval [CI]: 35.2-55.8; p < 0.0001) and very high NPV in all HPV-positive cases regardless of detected genotype (96.3%-100.0%). The risk (1-NPV) for CIN3+ in HRHPV16/18-positive/p16/Ki67-negative women was 0.0%. Superior diagnostic performance compared to cytology for detecting cervical cancer precursors indicates that p16/Ki67 dual-immunostain may be a highly effective tool of triage in primary HPV screening with limited HPV 16/18 genotyping in secondary cervical cancer prevention.

The Role of p16/Ki67 Dual Staining in Cervical Cancer Screening

Cervical cancer screening has enabled a decrease in the incidence and mortality of cervical cancer. Various screening modalities have been studied to date. In many countries, screening is still based on cervical cytology, where cervical cells obtained either on glass or in a liquid medium are examined under a microscope. However, the fact that the vast majority of cervical cancers are a result of persistent infection with high-risk human papillomaviruses (hr-HPV) has led to the implementation of primary HPV screening in many countries. Taking into consideration the fact that the majority of HPV infections are transient and do not cause cervical precancer, effective triage methods are needed to prevent an increase in colposcopy referrals. Among these, the most extensively investigated are HPV genotyping, HPV methylation, and p16/Ki67 dual staining. In this manuscript, we briefly summarize the current knowledge regarding different screening strategies for the prevention of cervical cancer, with a focus on p16/Ki67 dual staining. In addition, we provide an explanation regarding the rationale for the use of various screening modalities based on the molecular biology of cervical cancer and cervical precancerous lesions.

Diagnostic performance of p16/Ki-67 dual immunostaining at different number of positive cells in cervical smears in women referred for colposcopy

Background

The aim of the study was to evaluate the diagnostic accuracy of p16/Ki-67 dual immunostaining (p16/ Ki-67 DS) in cervical cytology and the number of positive p16/Ki-67 cells to diagnose high grade cervical intraepithelial neoplasia (CIN2+) in colposcopy population.

Subjects and methods

We performed an analysis on a subset cohort of 174 women enrolled within a large-scale randomised controlled human papillomavirus (HPV) self-sampling project organised as part of the population-based Cervical Cancer Screening Programme ZORA in Slovenia. This subset cohort of patients was invited to the colposcopy clinic, underwent p16/Ki-67 DS cervical cytology and had the number of p16/Ki-67 positive cells determined.

Results

Among analysed women, 42/174 (24.1%) had histologically confirmed CIN2+. The risk for CIN2+ was increasing with the number of positive cells (p < 0.001). The sensitivity of p16/Ki-67 DS for detection of CIN2+ was 88.1%, specificity was 65.2%, positive predictive value was 44.6% and negative predictive value was 94.5%.

Conclusions

Dual p16/Ki-67 immunostaining for the detection of CIN2+ has shown high sensitivity and high negative predictive value in our study, which is comparable to available published data. The number of p16/Ki-67 positive cells was significantly associated with the probability of CIN2+ detection. We observed a statistically significant and clinically relevant increase in specificity if the cut-off for a positive test was shifted from one cell to three cells.

Liquid-Based Screening Tests Results: HPV, Liquid-Based Cytology, and P16/Ki67 Dual-Staining in Private-Based Opportunistic Cervical Cancer Screening

The baseline data from the private-based opportunistic cervical cancer screening with HRHPV14, liquid-based cytology (LBC) and p16/Ki67 testing, and its quality assessment/quality control (QA/QC) tools are lacking. The age-stratified analysis of 30,066 screening tests results in a Polish population, including the investigation of HRHPV14 status, LBC, and p16/Ki67 dual-staining reporting rates, along with immediate histopathologic correlations, was conducted. For cytopathologic QA/QC, the College of American Pathologists (CAP) benchmarks and enhanced safety protocol were used. The NILM/ASC-US/LSIL/ASC-H/HSIL/AGC reporting rates were 93.9/3.4/2.0/0.22/0.24/0.11, respectively, with correlating HRHPV14-positive rates of 8.4/48.9/77.2/84.6/90.7/26.7. The reporting rates for HSIL (CIN2+) in HRHPV-positive women with NILM/ASC-US/LSIL/ASC-H/HSIL/AGC referred for a colposcopy with biopsy were 19.1/25.8/22.5/12.4/19.1/1.1% of the total HSIL (CIN2+). In total, of the 1130 p16/Ki67 tests, 30% were positive. In NILM HRHPV14-positive women with available histology result, HSIL(CIN2+) was detected in 28.3% of cases. In the first such large-scale Polish study presenting HRHPV14, informed LBC and HSIL (CIN2+) results, the reporting rates were highly consistent with data from American and other CAP-certified laboratories, confirming the possibility of using the 2019 ASCCP risk-based guidelines as one of the screening strategies outside of the US, in conditions of proper QA/QC. The private-based screening model can be effective in cervical cancer prevention, particularly in countries with low population coverage of public funds-based systems.

Discrepancy between Cytology and Histology in Cervical Cancer Screening: a Multicenter Retrospective Study (KGOG 1040)

BACKGROUND

Cervical cancer is the fourth common cancer in women worldwide. The Papanicolau test is the primary screening procedure to detect abnormal cervical cells. Colposcopy is the main procedure for discriminating high-grade cervical lesions. The study aimed at clarifying the discrepancy between cervical cytology and colposcopic biopsy histology as well as confounding factors.

METHODS

Eligible patients visited thirteen tertiary hospitals for colposcopic biopsy following cervical cytology and human papillomavirus (HPV) genotypes between January and December 2018. Baseline characteristics including age, body mass index (BMI), and parity were collected.

RESULTS

In our study, 3,798 eligible patients were included. Mean age of patients was 42.7 (19-88) years and mean BMI was 22.5 (16.9-34.1) kg/m². The referred cervical cytologic findings consisted of 495 normal, 1,390 atypical squamous cells of undetermined significance, 380 atypical squamous cells cannot exclude high-grade squamous intraepithelial lesion, 792 low-grade squamous intraepithelial lesion, 593 high-grade squamous intraepithelial lesion, 79 atypical glandular cells, 46 squamous cell carcinoma, and 23 adenocarcinoma. HPV-positive findings were found in 3,008 (79.2%) patients and were not detected in 914 (24.1%) cases. The risk of unexpected low-grade lesions from histology was higher in patients > 45 years (odds ratio [OR], 2.137; 95% confidence intervals [CIs], 1.475-3.096). In contrast, the risk of unexpected high-grade lesions from colposcopic biopsy was lower in patients ≥ 45 years (OR, 0.530; 95% CI, 0.367-0.747) and HPV 16/18 infection was higher than other HPV (OR, 1.848; 95% CI, 1.385-2.469).

CONCLUSION

Age and HPV genotypes were responsible for the discrepancies between cytology and histology. Precautions should be taken for women over the age of 45 in triage for colposcopy in order to avoid unnecessary testing.

P16/Ki-67 Immunostaining in the Triage of Postmenopausal Women With Low-Grade Cytology Results

OBJECTIVE

The interpretation of postmenopausal smears and the gynecological treatment of these patients can often be difficult. The objective of this study was to assess the performance of p16/Ki-67 dual-stained cytology as a triage of atypical squamous cells of undetermined significance and low-grade intraepithelial lesion cytology results in postmenopausal women.

METHODS

All consecutive atypical squamous cells of undetermined significance and low-grade intraepithelial lesion smears in 1-year period were collected and p16/Ki-67 immunostaining was performed retrospectively. The results were compared with histology results or long-term cytology follow-up in cases with no biopsy.

RESULTS

The sensitivity of p16/Ki-67 immunostaining for the detection of cervical intraepithelial neoplasia (CIN) 2 and CIN 3 was 57.1% and 85.0%, respectively. The specificity for the detection of CIN 2 was 94.3% and CIN 3 92.4%. Negative predictive values for the detection of CIN 2 and CIN 3 were 96.3% and 99.6%, respectively.

CONCLUSIONS

Dual p16/Ki-67 immunostaining is a useful additional method in postmenopausal patients with low-grade cytology. Considering the high specificity and negative predictive value in our study, we believe that it could be helpful in avoiding unnecessary referrals to colposcopy and thus reduce the cost of the program.

Role of Cervical Cancer Biomarkers p16 and Ki67 in Abnormal Cervical Cytological Smear

Introduction

Cervical cancer is the most common cancer in India. Screening for cervical cancer helps in marked reduction of invasive cervical cancers. The low sensitivity of Papanicolaou cytology (Pap smear) and high-risk human papillomavirus (HR-HPV) in excluding high-grade intraepithelial lesion (ASC-H) leads to unnecessary referrals to colposcopy-guided biopsy. The combined cervical cytology screening and HR-HPV have its own limitations and still need further standardization. Using additional biomarkers like staining with p16 and Ki-67 might help in triaging abnormal pap smear.

Materials and Methods

A prospective, cross-sectional study was performed over a period of 16 months in the Department of Obstetrics and Gynaecology, in collaboration with Department of Pathology. Study was conducted to know the efficacy of immunostaining with p16/Ki-67 in predicting the presence of significant lesion in cases of mild cytological atypia. PAP smears (conventional and LBC) along with P16, Ki-67 and available biopsies were correlated.

Results

Liquid-based cytology (LBC) was done in 2134 cases, out of which 46 cases showed abnormal cytological findings such as [22 atypical squamous cells of undetermined significance (ASCUS), 3 low-grade squamous intraepithelial lesion (LSIL), 8 atypical squamous cells cannot exclude high-grade lesion (ASC-H), 6 high-grade squamous intraepithelial lesion (HSIL), 5 squamous cell carcinoma (SCC), 2 adenocarcinoma, 1 atypical glandular cells of undetermined significance (AGUS)]. Immunostaining with p16 and Ki-67 was performed on 38 cases of abnormal cytological smears. Out of 38 abnormal cytology cases, 28 cases had shown co-staining for both p16 and Ki-67, suggestive of true HPV infection of the cells. Of the 38 cases, 07/14 ASCUS, 06/06 HSIL, 07/08 ASC-H, 05/05 squamous cell carcinoma and 02/02 adenocarcinoma also showed dual positivity for p16 and Ki-67. One case of AGUS was diagnosed, but the smear was unsatisfactory for immunocytochemical evaluation and excluded from the study. Three cases of LSIL were also diagnosed on cytological evaluation, and 1 of them however showed positivity for p16 and Ki-67 on immunocytochemistry (ICC). In the ASC-US group, the sensitivity and specificity of the immunostaining in diagnosing CIN2 + lesions were 87.51%, and in LSIL group, the sensitivity and specificity of the immunostaining in diagnosing CIN2 + lesions were 100%. p16/Ki-67 positivity also increased with cytological severity which in turn corresponded with histological findings: it reached from 50% in ASC-US to 100% in both HSIL and SCC categories.

Conclusion

This immunostaining with p16 and Ki67 can be a useful method in the triaging of the ASC-US and the LSIL group as considering the high sensitivity and specificity values.

Dual staining for p16/Ki-67 to detect high-grade cervical lesions: Results from the Screening Triage Ascertaining Intraepithelial Neoplasia by Immunostain Testing study

We compared clinical performance of p16/Ki-67 dual-stained cytology and human papillomavirus (HPV) genotyping, via different algorithms-alone, or in combination with cytology-to identify cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and grade 3 or worse (CIN3+) in women referred to as colposcopy. We included 492 cervical specimens (134 normal, 130 CIN1, 99 CIN2, 121 CIN3, 8 cancers) randomly selected from 1158 specimens with valid conventional cytology, HPV (cobas 4800 HPV test) and biopsy results. Dual-stained cytology was retrospectively performed (CINtec PLUS assay) on PreservCyt material; slides were read by a cytologist and confirmed by two pathologists, blinded to cytology, biopsy and genotyping results. Sensitivity and specificity (95% confidence intervals in parentheses) of dual-stained cytology to detect CIN2+ and CIN3+ were compared to other screening tests available for the same women. Positivity rate for dual-stained cytology increased with histological severity: 30.6% in normal, 41.5% in CIN1, 72.7% in CIN2, 86.8% in CIN3 and 87.5% in cancer. Dual-stained cytology alone had lower sensitivity than HPV testing for CIN2+ [80.7% (75.0-85.6) vs 89.9% (85.3-93.5)] and CIN3+ [86.8% (79.7-92.1) vs 92.3% (86.2-96.2)]. However, corresponding specificity values were higher [64.0% (57.9-69.8) vs 56.1% (49.8-62.1) for CIN2+; 54.0% (48.7-59.2) vs 44.4% (39.2-49.6) for CIN3+]. Combining dual-stained cytology with an ASC-US abnormality threshold decreased specificity to 31.4% (25.9-37.4) for CIN2+ and 24.2% (19.9-29.0) for CIN3+. The corresponding values considering low squamous intraepithelial lesion threshold values were 42.8% (36.8-49.0) and 35.0% (30.1-40.1). Dual-stained cytology and HPV testing exhibited similar performance, although the former improved the specificity by 7.9% and 9.6% for CIN2+ and CIN3+, respectively.

Diagnostic Accuracy of Cervical Pap Smear and Colposcopy in Detecting Premalignant and Malignant Lesions of Cervix

The objective of this study was to determine the diagnostic accuracy of pap smear and colposcopy in detecting the premalignant and malignant lesion of the cervix. In this cross-sectional study, a total number of 160 women who presented with abnormal clinical problem or routine checkup during a 6-month period were included. All the patients underwent pap smear and colposcopy by the same gynecologists team, and finally, cervical biopsy was performed in all the individuals. The demographic and clinical characteristics as well as the obstetrics history were recorded. The diagnostic accuracy of each test was calculated according to the biopsy as gold standard. The sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) were recorded and compared between two modalities. Overall, we included a total number of 160 patients with mean age of 37.6 ± 7.32 (ranging from 24 to 63) years. The sensitivity and specificity of pap smear were found to be 47.19% and 64.79%, respectively. The PPV and NPV of the pap smear were calculated to be 88.69% and 38.46%, respectively. The sensitivity and specificity, PPV, and NPV of the colposcopy were calculated as 64.72%, 52.74%, 76.32%, and 95.41%, respectively. The overall diagnostic accuracy of the pap smear and colposcopy was reported to be 82.2% and 96.3%, respectively. The results of this study demonstrate that colposcopy has a higher diagnostic accuracy in detecting cervical premalignant and malignant lesions compared to the pap smear.

Meta-analysis of the accuracy of p16 or p16/Ki-67 immunocytochemistry versus HPV testing for the detection of CIN2+/CIN3+ in triage of women with minor abnormal cytology

BACKGROUND

Women with atypical squamous cells of undetermined significance (ASC-US) can be triaged accurately with a high-risk human papillomavirus (hrHPV) test to identify those who need a referral. However, the triage of low-grade squamous intraepithelial lesion (LSIL) with hrHPV testing has very low specificity. Overexpression of p16, with or without Ki-67, indicates neoplastic transformation of human papillomavirus-infected cervical cells and may more accurately predict underlying cervical intraepithelial neoplasia of grade 3 or worse (CIN3+).

METHODS

A literature search was conducted in 3 bibliographic databases. Studies were selected if they included women with ASC-US or LSIL who were triaged with dual staining (p16/Ki-67) and/or p16 staining and, if available, with a comparator hrHPV test to detect cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) or CIN3+.

RESULTS

Thirty-eight studies were eligible. The sensitivity of p16 staining for CIN3+ was significantly lower than that of hrHPV DNA testing (ratio for ASC-US, 0.87; 95% confidence interval [CI], 0.78-0.97; ratio for LSIL, 0.86; 95% CI, 0.80-0.93). In contrast, the specificity of p16 staining was substantially higher with relative specificities of 1.60 (95% CI, 1.35-1.88) and 2.29 (95% CI, 2.05-2.56) for ASC-US and LSIL respectively. Dual staining was as sensitive as hrHPV DNA testing but was more specific (ratio for ASC-US, 1.65; 95% CI, 1.42-1.92; ratio for LSIL, 2.45; 95% CI, 2.17-2.77).

CONCLUSIONS

This meta-analysis confirms that p16 staining and p16/Ki-67 staining are more specific for CIN2+/CIN3+ than hrHPV DNA testing. Although p16 staining is less sensitive for CIN3+ than hrHPV DNA testing, dual staining has similar sensitivity.

Diagnostic performance of the E6/E7 mRNA-based Optimygene HR-HPV RT-qDx assay for cervical cancer screening

OBJECTIVES

Pap smear and high-risk human papillomavirus (HR-HPV) DNA testing are the most widely applied methods for cervical cancer screening, but both methods are limited by their low specificity and lack of association with patient prognoses. The aim of this study was to compare the clinical and prognostic significance of HPV E6/E7 mRNA as an early biomarker with cytology and HPV DNA detection in cervical cancer screening.

METHODS

This study evaluated the performance of the Optimygene HR-HPV RT-qDx assay, which is an HPV E6/E7 mRNA-based assay, to detect 16 HR-HPV subtypes: HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, and 69. The clinical evaluation was conducted using 563 ThinPrep liquid-based cytology samples and the results were compared to those of cytological and histological diagnoses and HPV DNA testing.

RESULTS

The clinical sensitivity and specificity of the Optimygene HR-HPV RT-qDx assay for the detection of high-grade lesions, according to cervical cytology, were 92.4% (95% confidence interval (CI) 0.9167-0.9972, p<0.0001) and 96.9% (95% CI 0.8632-0.9524, p<0.0001), respectively; they were 85.9% (95% CI 0.7631-0.9211, p<0.0001) and 82.5% (95% CI 0.7491-0.8825, p<0.0001), respectively, for CIN2+. This assay showed a higher specificity and positive predictive value for cytological and histological diagnosis than HPV DNA testing. Overall, the agreement between the Optimygene HR-HPV RT-qDx assay and HPV DNA testing in cytological and histological diagnosis was 87.9% (κ=0.76, 95% CI 0.7054-0.8128, p<0.0001) and 90.5% (k=0.81, 95% CI 0.7338-0.8878, p<0.0001), respectively. In this study, the most frequently detected HPV genotypes among HR-HPV-positive women were HPV 16 (37.9%), HPV 33-58 (21.5%), and HPV 18 (11.4%).

CONCLUSIONS

These findings suggest that the higher specificity and positive predictive value of the Optimygene HR-HPV RT-qDx assay are valuable for predicting insignificant HPV DNA infections among patients with a borderline cytological diagnosis. This assay could be used to prevent unnecessary biopsy procedures and the over-referral of patients with transient HPV infections, as well as reduce patient anxiety during the follow-up period.

Dual staining for p16/Ki67 is a more specific test than cytology for triage of HPV-positive women

Globally, cervical cancer (CC) screening is moving from cytology-based to HPV screening or a combination of both (co-testing). Most HPV-positive women clear the virus and do not develop relevant disease. Additional triage approaches are needed to reduce unnecessary colposcopy referrals. The p16/Ki67 dual stain cytology test (DSCT) is one of the most promising, but it has not (yet) been included as a recommendation in European guidelines. Previous studies in Spain on this issue are lacking. We studied the performance of p16/Ki67 DSCT for the triage of HPV-positive women in Navarra to detect precursor lesions (PLs) and CC compared to cytology only. We selected 1865 HPV-positive women with p16/Ki67 DSCT results and 304 women with an available biopsy result. Sensitivity, specificity and predictive values of the p16/Ki67 DSCT to detect underlying PLs and CC compared to cytology were calculated, using the biopsy as the gold standard. Cytology and p16/Ki67 DSCT showed similar sensitivity (99.0% vs. 98.0%), but cytology had significantly lower specificity (6.9 vs. 39.1%). Of the CIN2+/HPV+ women, triage using cytology only would have resulted in 40.2% true PLs and CC, while using p16/Ki67 DSCT this was 98.0% qualifying the women for colposcopy referral. Our results show that p16/Ki67 DSCT detects more than twice as many true PLs and CC than cytology only in this population. Thus, this test can be considered as an important additional tool in HPV testing-based screening strategies, to avoid unnecessary colposcopy referrals and to reduce health care costs.

Performance of P16/Ki67 dual staining in triaging hr-HPV-positive population during cervical Cancer screening in the younger women

BACKGROUND

Cervical cancer is the most common malignancy from the female reproductive tract, and usually develops from low-grade or high-grade squamous intraepithelial lesions (LSIL or HSIL). Detecting the precancerous lesion during the LSIL-HSIL-invasive cancer sequelae can effectively interrupt the oncogenesis and decrease the incidence of invasive carcinoma. The aim of this study is to evaluate the performance of P16/Ki67 dual staining in triaging hr-HPV-positive population.

METHODS

Conventional gynecological examination, cervical cytology and hr-HPV testing were given to all patients. Specimens were collected for cytology examination and HPV genotyping. According to cytology results, patients were divided into cervical cancer group, HSIL group, LSIL group and benign lesion group. Sensitivity and specificity of the dual staining method in each histopathologic group was obtained and compared.

RESULTS

Among the108 patients participated in the study, 65 were diagnosed as normal, 15 as LSIL, 20 as HSIL and 8 as CC, by histopathologic examination. Dual staining of p16/Ki67 on cytology specimen provided a positive predictive value of 86% and the negative predictive value of 96%. The sensitivity approached 96.43% when combining ThinPrep cytological test (TCT) with the dual staining, with a specificity of 60% in detecting HSIL. Joint detection of TCT and p16/Ki67 dual staining displayed the highest specificity among all the attempted combinations of detection methods.

CONCLUSIONS

This study demonstrated that p16/Ki-67 dual staining represents an effective method for cervical cancer screening. Application of this method could lead to a reduction of unnecessary colposcopy referrals and misdiagnosis.

Evaluation of p16/Ki-67 dual-stained cytology as triage test for high-risk human papillomavirus-positive women

The aim of this study was to evaluate the clinical utility of p16/Ki-67 dual staining, for the identification of CIN in high-risk HPV-positive women from a non-responder screening cohort. P16/Ki-67 dual staining, Pap cytology, and HPV16/18 genotyping were performed on physician-taken liquid-based samples from 495 women who tested high-risk HPV positive on self-sampled material (PROHTECT-3B study). Different triage strategies involving p16/Ki-67 dual staining were evaluated for sensitivity, specificity, and predictive value for ≥CIN2 and ≥CIN3, and compared to Pap cytology with a threshold of atypical cells of undetermined significance. Centrally revised histology or an adjusted endpoint with combined high-risk HPV negative and cytology negative follow-up at 6 months was used as gold standard. Pap cytology (threshold atypical cells of undetermined significance) triage of high-risk HPV-positive samples showed a sensitivity of 93% (95% confidence interval: 85-98) with a specificity of 49% (95% confidence interval: 41-56) for ≥CIN3. Three triage strategies with p16/Ki-67 showed a significantly increased specificity with similar sensitivity. P16/Ki-67 triage of all high-risk HPV-positive samples had a sensitivity of 92% (95% confidence interval: 84-97) and a specificity of 61% (95% confidence interval: 54-69) for ≥CIN3. Applying p16/Ki-67 triage to only high-risk HPV-positive women with low-grade Pap cytology showed a similar sensitivity of 92% (95% confidence interval: 84-97), with a specificity for ≥CIN3 of 64% (95% confidence interval: 56-71). For high-risk HPV-positive women with low-grade and normal Pap cytology, triage with p16/Ki-67 showed a sensitivity of 96% (95% confidence interval: 89-99), and a specificity of 58% (95% confidence interval: 50-65). HPV16/18 genotyping combined with Pap cytology showed a sensitivity and specificity for ≥CIN3 similar to Pap cytology with an atypical cells of undetermined significance threshold. Because the quality of Pap cytology worldwide varies, and differences in sensitivity and specificity are limited between the three selected strategies, p16/Ki-67 triage of all high-risk HPV-positive samples would be the most reliable strategy in triage of high-risk HPV-positive women with an increased specificity and similar sensitivity compared with Pap cytology triage.

Diagnostic performance of dual-staining cytology for cervical cancer screening: A systematic literature review

Cervical cancer screening saves lives. Secondary prevention in cervical cancer screening relies on the results of primary cytology and/or HPV testing. However, primary screening with cytology has a low sensitivity, and HPV screening has a low specificity. This means that either cancers are missed, or women are over-treated. To improve performance outcomes, the concept of dual-stain cytology (CINtec^® PLUS Cytology test) has been introduced. In this approach, additional staining with p16/Ki-67 is performed in cases where cytology results are abnormal (LSIL or ASCUS) and/or HPV-positive. Another way to describe this approach might be "diagnostic" cytology. In order to assess the value of this "diagnostic cytology", a systematic literature review was conducted of dual-stain cytology performance across multiple studies until May 2016. In a Belgian screening population (women age 25-65 years), dual-stain cytology was significantly more sensitive (66%) and slightly less specific (-1.0%) than cytology. In the population referred to colposcopy or with abnormal cytology (ASCUS, LSIL), dual-staining showed a significantly higher increase in specificity, and a slightly lower sensitivity than HPV testing. Specificity gains resulted in fewer false positives and an increase in the number of correct referrals to colposcopy. Dual-staining with p16/Ki-67 cytology is an attractive biomarker approach for triage in cervical cancer screening.

Predictive value of p16/Ki-67 immunocytochemistry for triage of women with abnormal Papanicolaou test in cervical cancer screening: a systematic review and meta-analysis

BACKGROUND

The Papanicolaou (Pap) test is one screening strategy used to prevent cervical cancer in developed countries. The p16/Ki-67 immunocytochemistry is a triage test performed on Pap smears in women with atypical squamous cells of undetermined significance (ASCUS) or low grade squamous intraepithelial lesion.

OBJECTIVE

Our objective was to review studies investigating the diagnostic performance of p16/Ki-67 dual stain for triage of women with abnormal Pap tests.

DESIGN

We conducted a systematic review and meta-analysis of diagnostic test accuracy studies.

SETTINGS

We followed the protocol of systematic review of diagnostic accuracy studies.

PATIENTS AND METHODS

We searched PubMed, The Cochrane Library, BioMed Central, and ClinicalTrials.gov for relevant studies. We included research that assessed the accuracy of p16/Ki-67 dual stain and high risk human papillomavirus testing for triage of abnormal Pap smears. Review articles and studies that provided insufficient data to construct 2.2 tables were excluded. Data synthesis was conducted using a random-effects model.

MAIN OUTCOME MEASURES

Sensitivity and specificity.

RESULTS

In seven studies encompassing 2628 patients, the pooled sensitivity and specificity of p16/Ki-67 for triage of abnormal Pap smear results were 0.91 (95% CI, 0.89 to 0.93) and 0.64 (95% CI, 0.62 to 0.66), respectively. No study used a case-control design. A subgroup analysis involving liquid-based cytology showed a sensitivity of 0.91 (95%CI, 0.89 to 0.93) and specificity of 0.64 (95%CI, 0.61 to 0.66).

CONCLUSIONS

Our meta-analysis of p16/Ki-67 dual stain studies showed that the test achieved high sensitivity and moderate specificity for p16/Ki-67 immunocytochemistry for high-grade squamous intraepi.thelial lesion and cervical cancer. We suggest that p16/Ki-67 dual stain might be a reliable ancillary method identifying high-grade squamous intraepithelial lesions in women with abnormal Pap tests.

LIMITATIONS

No study in the meta-analysis examined the accuracy of the p16/Ki-67 dual stain for inter.pretation of glandular neoplasms.

Triage of ASC-H: A meta-analysis of the accuracy of high-risk HPV testing and other markers to detect cervical precancer

BACKGROUND

Women with a cytological diagnosis of atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H) are usually immediately referred for colposcopy. However, triage may reduce the burden of the diagnostic workup and prevent overtreatment.

METHODS

A meta-analysis was conducted to assess the accuracy of high-risk human papillomavirus (hrHPV) testing and testing for other molecular markers for the detection of grade 2 cervical intraepithelial neoplasia or worse (CIN2+) or grade 3 cervical intraepithelial neoplasia or worse (CIN3+) in women with ASC-H. An additional question that was assessed was whether triage would be useful in light of the relatively high pretriage probability of underlying precancer.

RESULTS

The pooled absolute sensitivity and specificity of the Hybrid Capture 2 (HC2) assay for CIN2 + (derived from 19 studies) were 93% (95% confidence interval [CI], 89%-95%) and 45% (95% CI, 41%-50%), respectively. p16(INK4a) staining (only 3 studies) had similar sensitivity (93%; 95% CI, 75%-100%) but superior specificity (specificity ratio, 1.69) to HC2 for CIN2+. Testing for paired box 1 gene methylation (only 1 study) showed a superior specificity of 95% (specificity ratio, 2.08). The average pretest risk was 34% for CIN2 + and 20% for CIN3+. A negative HC2 result decreased this to 8% and 5%, respectively, whereas a positive result upgraded the risk to 47% and 28%, respectively.

CONCLUSIONS

Because of the high probability of precancer with a diagnosis of ASC-H, the utility of triage is limited. The usual recommendation for referring women with ASC-H for colposcopy is not altered by a positive triage test, whatever test is used. A negative hrHPV DNA or p16(INK4a) test may allow repeat testing, but this recommendation will depend on local decision thresholds for referral.

The Application of Classification and Regression Trees for the Triage of Women for Referral to Colposcopy and the Estimation of Risk for Cervical Intraepithelial Neoplasia: A Study Based on 1625 Cases with Incomplete Data from Molecular Tests

OBJECTIVE

Nowadays numerous ancillary techniques detecting HPV DNA and mRNA compete with cytology; however no perfect test exists; in this study we evaluated classification and regression trees (CARTs) for the production of triage rules and estimate the risk for cervical intraepithelial neoplasia (CIN) in cases with ASCUS+ in cytology.

STUDY DESIGN

We used 1625 cases. In contrast to other approaches we used missing data to increase the data volume, obtain more accurate results, and simulate real conditions in the everyday practice of gynecologic clinics and laboratories. The proposed CART was based on the cytological result, HPV DNA typing, HPV mRNA detection based on NASBA and flow cytometry, p16 immunocytochemical expression, and finally age and parous status.

RESULTS

Algorithms useful for the triage of women were produced; gynecologists could apply these in conjunction with available examination results and conclude to an estimation of the risk for a woman to harbor CIN expressed as a probability.

CONCLUSIONS

The most important test was the cytological examination; however the CART handled cases with inadequate cytological outcome and increased the diagnostic accuracy by exploiting the results of ancillary techniques even if there were inadequate missing data. The CART performance was better than any other single test involved in this study.

High performance of combined HPV testing and genotyping for HPV16/18/52/58 in triaging women with minor cervical cytological abnormalities in northern Thailand

Human papillomavirus (HPV) infection is an important cause of cervical cancer. Screening with cytology or combined cytology and HPV testing helps to detect early cervical cancers and precancerous lesions (high-grade squamous intraepithelial lesion or worse [HSIL+]). Minor cytological abnormalities (atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion) account for the majority of abnormal cervical cytology results, but only 10-20% of women with minor cytological abnormalities have histologic HSIL+. Triage tests are useful to identify the high-risk patients and reduce the colposcopy burden. This study was aimed to evaluate the triage performance of combined HPV DNA testing and genotyping. Cervical samples from women with minor cytological abnormalities, who underwent colposcopy at Chiang Mai University Hospital in northern Thailand between October 2010 and February 2014, were tested for HPV DNA using Hybrid Capture 2 (HC2). Genotyping was performed using Linear Array assay. Of 223 women with cervical histology confirmation, histologic HSIL+ was detected in 25 women (11.2%). The sensitivity, specificity, positive predictive value, and negative predictive value of 3 triage methods for histologic HSIL+ were; 100%, 47.5%, 19.4%, and 100% by HC2 only; 40.0%, 88.4%, 30.3%, and 92.1% by combined HC2 and genotypes HPV16/18; and 96.0%, 75.8%, 33.3%, and 99.3% by combined HC2 and genotypes HPV16/18/52/58. Triage using combined HC2 and genotypes HPV16/18/52/58 showed significantly greater area under the receiver operating curve than the other 2 methods (P < 0.001). Combined HPV DNA testing and genotyping for HPV16/18/52/58 is useful for triaging women with minor cervical cytological abnormalities in northern Thailand.

Performance of the R-way Colposcopic Evaluation System in Cervical Cancer Screening

OBJECTIVE

To investigate the diagnostic value of the R-way colposcopic evaluation system (R-way system) in cervical cancer screening.

MATERIALS AND METHODS

Between August 2013 and August 2014, a total of 1,059 cases referred to colposcopy in Peking University First Hospital were studied using both the R-way system and conventional colposcopy. Our study evaluated and compared the diagnostic ability of the two methods in detecting high-grade lesions and cervical cancer (hereinafter called CIN2+). Evaluation indicators including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Youden index and the area under the curve (AUC) of the receiver operating characteristic (ROC) were calculated.

RESULTS

The R-way system had a slightly lower specificity (94.5%) than conventional colposcopy (96.0%) for CIN2+ detection (P=0.181). However, the sensitivity (77.8%) was significantly higher than with the conventional colposcopic method (46.6%) (χ2=64.351, P<0.001). In addition, the AUC of the ROC for CIN2+ detection using the R-way system (0.839) was larger than that with conventional colposcopy (0.731) (Z=4.348, P<0.001). If preliminary result had been drawn from cervical exfoliated cytology before colposcopy referral, combination of the R-way system with cytology could increase the sensitivity to 93.9% for CIN2+ detection (excluding ASCUS\LSIL), confirmed by multipoint biopsy or ECC.

CONCLUSIONS

The diagnostic value of the R-way evaluation system is higher than that of conventional colposcopic evaluation in cervical cancer screening. Moreover, taking the ease of use and standardized quality control management into account, the R-way system is highly preferable.

Prospective evaluation of p16/Ki-67 dual-stained cytology for managing women with abnormal Papanicolaou cytology: PALMS study results

BACKGROUND

Testing for the presence of the human papillomavirus (HPV) is widely accepted for triaging Papanicolaou cytology results categorized as atypical squamous cells of undetermined significance (ASC-US). In contrast, HPV testing has limited use in triaging cytological low-grade squamous intraepithelial lesions (LSILs) due to prevalence rates of typically >80%. In the current study, the authors assessed the diagnostic performance of p16/Ki-67 dual-stained cytology in triaging ASC-US and LSIL cases within the prospective, multicentric Primary ASC-US LSIL Marker Study (PALMS).

METHODS

A total of 575 ASC-US cases and 529 LSIL cases from a cohort of 27,349 women who were prospectively enrolled into the PALMS study in 5 European countries were tested with p16/Ki-67 dual-stained cytology and Hybrid Capture 2 (HC2) HPV testing. Colposcopy-guided biopsy results of cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) were used as clinical endpoints.

RESULTS

p16/Ki-67 dual-stained cytology demonstrated comparable (ASC-US: 94.4% for dual-stained cytology vs 100% for HC2 testing; P = .317) or lower (LSIL: 85.7% for dual-stained cytology vs 98.4% for HC2 testing; P = .005) sensitivity for CIN2+, but higher levels of specificity compared with HC2 HPV testing in both ASC-US (78.7% vs 60.4%; P<.001) and LSIL (53.3% vs 15.6%; P<.001) cases. Positive predictive values for CIN2+ were substantially higher for dual-stained cytology versus HC2 HPV testing, especially in LSIL, and in ASC-US cases for women aged <30 years.

CONCLUSIONS

The clinical usefulness and efficiency of triaging women with ASC-US or LSIL Papanicolaou cytology results by p16/Ki-67 dual-stained cytology testing has been confirmed in this prospective, pan-European study. The high positive predictive value of dual-stained cytology for the presence of high-grade CIN may help to reduce the number of unnecessary colposcopy referrals.

Diagnostic performance of HPV E6/E7, hTERT, and Ki67 mRNA RT-qPCR assays on formalin-fixed paraffin-embedded cervical tissue specimens from women with cervical cancer

Human papillomavirus (HPV) is a major cause of cervical cancer, which is the third most common cancer in women. Human telomerase reverse transcriptase (hTERT) and Ki67 are tumor cell markers indicating cancer cell proliferation in cancer patients, and activation of hTERT and Ki67 leads to progressive cervical carcinogenesis. In the present study, we evaluated the CervicGen HPVE6/E7 mRNA RT-qDx assay, which detects 16 HPV high-risk (HR) genotypes (HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68 and 69), and the CervicGen hTERT and Ki67 mRNA RT-qDx assay using 117 formalin-fixed paraffin-embedded (FFPE) cervical cancer tissue samples. The diagnostic validity of the CervicGen HPV RT-qDx assay for detecting histologically proven prevalent squamous cell carcinoma (SCC) was 94% sensitivity, 100% specificity, 77.8% positive predictive value (PPV), and 78.9% negative predictive value (NPV). The most common HPV genotypes detected in FFPE cervical cancer tissue samples were HPV 16 (56%) and HPV 18 (10%). The positivity rate of hTERT and Ki67 mRNA expressions in FFPE cervical cancer tissue samples on RT-qPCR was 65% and 93% respectively. Moreover, the positivity rates were 92% for a combination of HPV E6/E7 and hTERT mRNA expressions, 97% for HPV E6/E7 and Ki67 mRNA expressions, and 99% (99/100) for the combination of HPV E6/E7, hTERT, and Ki67 mRNA expressions. These data showed that SSC FFPE cervical cancer tissue samples correlated more strongly with high Ki67 mRNA expressions than with hTERT mRNA expressions. Notably, hTERT and Ki67 mRNA expression level was increased in high-grade cervical lesions, but was very low in normal samples. Our findings suggest that the combination of HPV E6/E7, hTERT, and Ki67 mRNA expression levels could be used in a complementary manner in diagnosing high-grade cervical lesions. Further studies are required to evaluate these assays as a useful predictive tool for screening low-grade cervical lesions.