How to evaluate emerging technologies in cervical cancer screening?

HPV Testing and its Role in Cervical Cancer Screening

The recognition that persistent infection with carcinogenic human papillomavirus (HPV) is a necessary cause of cervical precancer and cancer has led to the introduction of HPV testing into cervical cancer screening, either as a primary screening test or in conjunction with cervical cytology (i.e., co-testing). HPV testing has much higher sensitivity for detection of cervical precancer and provides greater long-term reassurance if negative compared to cytology. However, most HPV infections are transient, and do not progress to invasive cancer, thus triage tests are required to identify individuals who should be referred to colposcopy for diagnostic evaluation. This chapter begins with a description of the biology, natural history, and epidemiology of HPV as a foundation for understanding the role of HPV in cervical carcinogenesis. This section is followed by a detailed discussion regarding the introduction of HPV-based testing and triage into cervical cancer screening and management. Summarized triage tests include cervical cytology, HPV genotyping, p16/Ki-67 dual stain, and HPV and cellular methylation markers. The final section of this chapter includes an important discussion on cervical cancer disparities, particularly within the United States, followed by concluding remarks.

Meta-analysis of agreement/concordance statistics in studies comparing self- versus clinician-collected samples for HPV testing in cervical cancer screening

We conducted a meta-analysis of test agreement/concordance between human papillomavirus (HPV) testing in self-collected versus clinician-collected samples in 26 studies (10,071 participants) updating a previous meta-analysis on accuracy for cervical precancer. Pooled overall agreement was 88.7% (95%CI: 86.3%-90.9%), positive agreement was 84.6% (95%CI: 79.9%-88.7%), negative agreement was 91.7% (95%CI: 89.1%-94.0%), and kappa was 0.72 (95%CI: 0.66-0.78). Subgroup meta-analyses suggested higher overall agreement for target amplification-based DNA assays (90.4%) compared to signal amplification-based DNA assays (86.7%) (p=0.175) or RNA assays (82.3%) (p<0.001). HPV test agreement/concordance targets may provide criteria to extend existing validations towards alternative sampling approaches and devices/storage media. This article is protected by copyright. All rights reserved.

Comparative performance of the human papillomavirus test and cytology for primary screening for high-grade cervical intraepithelial neoplasia at the population level

The World Health Organization recommends high-risk human papillomavirus (hrHPV)-based screening for women 39 to 49 years, based on the greater accuracy of hrHPV-based screening for cervical cancer detection. Many cervical cancer screening programs have incorporated hrHPV testing and multiple early cervical cancer detection strategies have been evaluated, mostly under controlled conditions. However, there are few evaluations of combined hrHPV and cytology strategies post-implementation at the population level. Our study sought to estimate the relative yield of hrHPV testing compared to cervical cytology, as a primary screening test for cervical intraepithelial neoplasia grade 2+ (CIN2+), used at the population level. We analyzed screening data from Mexico's public cervical cancer prevention program from 2010 to 2015 in women 35 to 64 years. The study population consisted of two cohorts: one from a total of 2 881 962 cytology-based screening tests and another from a total of 2 004 497 hrHPV-based screening tests, which are concurrent in time. We performed a relative yield analysis using Poisson regression models to compare the effectiveness of hrHPV testing for CIN2+ with cervical cytology. A total of 4 886 459 records were analyzed, including 23 999 biopsies; 0.12% (n = 6166) had a CIN2+ histologic diagnosis. hrHPV testing with cytological triage detects twice as many CIN2+ cases as screening using cytology alone.

Direct bisulphite conversion of cervical samples for DNA methylation analysis

Sodium bisulphite conversion of DNA to separate methylated from unmethylated cytosines is a standard for methylation analysis. This study evaluated a direct cell conversion protocol on cervical samples as alternative to isolated genomic DNA as input.

Clinician-collected cervical samples (n = 120) were subjected to a direct conversion protocol, or genomic DNA was isolated with a fixed amount used for subsequent bisulphite conversion. Converted samples were compared for ACTB control gene and methylation of FAM19A4 and miR124-2 genes using quantitative methylation-specific PCR (QIAsure Methylation Test).

Direct conversion resulted in a high success rate, i.e., 119/120 (99.2%) samples reported a valid test result. ΔΔCq values of FAM19A4 and miR124-2 were significantly correlated between both protocols (Spearman Rho 0.708 and 0.763, respectively, all p-values = 0.000). Agreement between both the bisulphite protocols was demonstrated by Bland–Altman plots.

A direct cell conversion protocol shows good technical and analytical performance and offers a streamlined workflow for methylation analysis.

Cervical Cancer Screening: Comparison of Conventional Pap Smear Test, Liquid-Based Cytology, and Human Papillomavirus Testing as Stand-alone or Cotesting Strategies

BACKGROUND

Some countries have implemented stand-alone human papillomavirus (HPV) testing while others consider cotesting for cervical cancer screening. We compared both strategies within a population-based study.

METHODS

The MARZY cohort study was conducted in Germany. Randomly selected women from population registries aged ≥30 years (n = 5,275) were invited to screening with Pap smear, liquid-based cytology (LBC, ThinPrep), and HPV testing (Hybrid Capture2, HC2). Screen-positive participants [ASC-US+ or high-risk HC2 (hrHC2)] and a random 5% sample of screen-negatives were referred to colposcopy. Post hoc HPV genotyping was conducted by GP5+/6+ PCR-EIA with reverse line blotting. Sensitivity, specificity (adjusted for verification bias), and potential harms, including number of colposcopies needed to detect 1 precancerous lesion (NNC), were calculated.

RESULTS

In 2,627 screened women, cytological sensitivities (Pap, LBC: 47%) were lower than HC2 (95%) and PCR (79%) for CIN2+. Cotesting demonstrated higher sensitivities (HC2 cotesting: 99%; PCR cotesting: 84%), but at the cost of lower specificities (92%-95%) compared with HPV stand-alone (HC2: 95%; PCR: 94%) and cytology (97% or 99%). Cotesting versus HPV stand-alone showed equivalent relative sensitivity [HC2: 1.06, 95% confidence interval (CI), 1.00-1.21; PCR: 1.07, 95% CI, 1.00-1.27]. Relative specificity of Pap cotesting with either HPV test was inferior to stand-alone HPV. LBC cotesting demonstrated equivalent specificity (both tests: 0.99, 95% CI, 0.99-1.00). NNC was highest for Pap cotesting.

CONCLUSIONS

Cotesting offers no benefit in detection over stand-alone HPV testing, resulting in more false positive results and colposcopy referrals.

IMPACT

HPV stand-alone screening offers a better balance of benefits and harms than cotesting.See related commentary by Wentzensen and Clarke, p. 432.

Performance of DNA methylation assays for detection of high-grade cervical intraepithelial neoplasia (CIN2+): a systematic review and meta-analysis

Background

To conduct a meta-analysis of performance of DNA methylation in women with high-grade cervical intraepithelial neoplasia (CIN2+).

Methods

Medline and Embase databases were searched for studies of methylation markers versus histological endpoints. Pooled sensitivity, specificity and positive predictive value (PPV) for CIN2+ were derived from bivariate models. Relative sensitivity and specificity for CIN2+ compared to cytology and HPV16/18 genotyping were pooled using random-effects models.

Results

Sixteen thousand three hundred thirty-six women in 43 studies provided data on human genes (CADM1, MAL, MIR-124-2, FAM19A4, POU4F3, EPB41L3, PAX1, SOX1) and HPV16 (L1/L2). Most (81%) studies evaluated methylation assays following a high-risk (HR)-HPV-positive or abnormal cytology result. Pooled CIN2+ and CIN3+ prevalence was 36.7% and 21.5%. For a set specificity of 70%, methylation sensitivity for CIN2+ and CIN3+ were 68.6% (95% CI: 62.9–73.8) and 71.1% (95% CI: 65.7–76.0) and PPV were 53.4% (95% CI: 44.4–62.1) and 35.0% (95% CI: 28.9–41.6). Among HR-HPV+ women, the relative sensitivity of methylation for CIN2+ was 0.81 (95% CI: 0.63–1.04) and 1.22 (95% CI: 1.05–1.42) compared to cytology of atypical squamous cells of undetermined significance, or greater (ASCUS+) and HPV16/18 genotyping, respectively, while relative specificity was 1.25 (95% CI: 0.99–1.59) and 1.03 (95% CI: 0.94–1.13), respectively.

Conclusion

DNA methylation is significantly higher in CIN2+ and CIN3+ compared to ≤CIN1. As triage test, DNA methylation has higher specificity than cytology ASCUS+ and higher sensitivity than HPV16/18 genotyping.

Diagnostic Accuracy of Conventional Cell Blocks Along with p16INK4 and Ki67 Biomarkers as Triage Tests in Resource-poor Organized Cervical Cancer Screening Programs

Background:

Liquid based cytology with dual biomarkers has improved sensitivity and specificity in detecting high grade cervical intraepithelial neoplasia (CIN). In low resource settings, especially in organized camps, LBC is costly and immunohistochemistry on conventional pap smears is difficult to standardize with consumption of lots of reagents. In present study, to improve the accuracy of conventional pap smears and reduce the cost of biomarker testing, we evaluated conventional cell blocks (CCBs) preparations with biomarkers to detect high-grade CIN in resource-poor organized screening programs. We also studied feasibility of using CCB as primary screening test.

Material and Methods:

A total of 350 participants were included in the cross-sectional evaluation of the screening tests. A conventional Papanicolaou (Pap) smear was obtained, and another sample was then collected and placed in 10% neutral buffered formalin for CB preparation. All abnormal Pap tests and CBs were stained for the biomarkers p16INK4a and Ki67. Histopathology with p16INK4a expression was considered the gold standard. Diagnostic tests were compared using MacNemar’s test and receiver operating curves were plotted.

Results:

The sensitivity, specificity, and diagnostic accuracy of CCB cytology, CB + p16 cytology and CB + p16Ki67 cytology for detecting CIN2+ lesions were 85.71%, 100%, 97.44%; 100%, 93.75%, 94.87%; and 85.71%, 100%, 97.44%, respectively. The Ki67 index could further categorize low grade lesions into lesions with low proliferative index and with high proliferative index (Pearson chi-square p value <0.001).

Conclusion:

If CB preparation is standardized, CCB cytology with biomarkers can have better diagnostic accuracy than conventional cytology, can classify low grade lesions likely to progress and can be used in field settings as primary screening test.

VALHUDES: A protocol for validation of human papillomavirus assays and collection devices for HPV testing on self-samples and urine samples

BACK GROUND

Systematic reviews have concluded that hrHPV DNA testing using target-amplification tests is as accurate on vaginal self-samples as on clinician-taken specimens for the detection of cervical precancer. However, insufficient evidence is available for specific HPV assay/self-sample device combinations.

OBJECTIVES

The VALHUDES protocol is designed as a diagnostic test accuracy study that aims to compare the clinical sensitivity and specificity of particular hrHPV assay(s) on vaginal self-samples and first-void-urine, collected in agreement with standardized protocols, with hrHPV testing on matched clinician-taken samples.

STUDY DESIGN

Five hundred enrolled women referred to a colposcopy clinic are invited to collect a first-void urine sample and one or more vaginal self-samples with particular devices before collection of a cervical sample by a clinician. Sample sets are subsequently analysed in a laboratory accredited for HPV testing. Disease verification for all enrolled patients is provided by colposcopy combined with histological assessment of biopsies.

RESULTS

A first VALHUDES study has started in Belgium in December 2017 with enrolment from four colposcopy centres. The following assays are foreseen to be evaluated: RealTime High Risk HPV assay (Abbott), cobas-4800 and -6800 (Roche), Onclarity (BD), Xpert HPV (Cepheid) and Anyplex II HPV HR (Seegene).

CONCLUSION

Given empirical evidence that the relative accuracy of HPV-testing on self- vs clinician-samples is robust across clinical settings, the VALHUDES protocol offers a framework for validation of HPV assay/self-sample device combinations that can be translated to a primary screening setting.

The effect of p16/Ki-67 and p16/mcm2 on the detection of cervical intraepithelial neoplasia: a prospective study from China

2,067 women who underwent cervical cancer screening were included in this study. p16/Ki-67 and p16/mcm2 were performed on the remaining liquid-based cytology (LBC) samples of 125 HPV-positive women and 114 randomly selected HPV-negative women. Women with HR-HPV infection or cytological abnormalities (≥ASC-US) were referred for colposcopy and biopsy. A third-year follow up visit was performed on all women except for CIN2+. The expression of p16/Ki-67 and p16/mcm2 in the HPV16/18 group and in the other 12 HR-HPV group was significantly higher than that in HPV negative group (P<0.05), with odds ratios (ORs) of 16.27 (95% CI: 4.38-60.47) and 4.52 (95% CI: 2.16-9.45) for p16/Ki-67, and 31.28 (95% CI: 6.33-154.56) and 9.10 (95% CI: 4.52-18.33) for p16/mcm2, respectively. The sensitivities to detect CIN2+ and CIN3 + were 94.1% (95% CI: 73.0-99.0) and 92.9% (95% CI: 68.5-98.7) for p16/Ki-67, and 88.2% (95% CI: 65.7-96.7) and 85.7% (95% CI: 60.1-96.0) for p16/mcm2, respectively. Both the sensitivities of the two biomarkers were significantly higher than that of LBC and HPV16/18 genotyping (P<0.05). The three-year cumulative risks of CIN2+ were 69.0%, 48.4%, 34.8% and 50.0% for p16/Ki-67, p16/mcm, LBC and HPV16/18 genotyping. Women who tested positive on both p16/Ki-67 and p16/mcm2 at baseline had the highest RR value (39.64 [95% CI: 9.78-160.72]) of progressing to CIN2+ when compared to those who were negative for both. To conclude, p16/Ki-67 and p16/mcm2 dual staining can enhance the sensitivity of cytology in a single round of screening, and they can be predictors of high grade cervical lesions in the following years.

Characterization of JAK2 V617F (1849 G > T) Mutation in Cervical Cancer Related to Human Papillomavirus and Sexually Transmitted Infections

Background

Human papillomavirus (HPV) genotypes that infect the genital tract play a main etiologic role in cervical cancer progression. Other environmental factors, such as sexually transmitted diseases and the host genetic pattern, contribute to infection persistence of the uterus and cervical epithelium in sustaining their malignancy. The Janus kinase 2 is a non-receptor tyrosine kinase in cell signaling process of tumor genesis. In the present study, JAK2 V167F mutation was distinguished in women with sexually transmitted infections, such as Herpes simplex virus 2, Chlamydia trachomatis and Mycoplasma genitalium and cervical cancer.

Methods

This case-control survey was performed on 195 liquid based cytology of women specimens. Fifty, 98, and 47 samples were from women with known cervical cancer, HPV positive and HPV negative, respectively. Single nucleotide polymorphism analysis, sexually transmitted infections detection and HPV genotyping were carried out using approved PCR- RFLP, in-house multiplex TaqMan Real Time PCR and the reverse dot blot hybridization assay.

Results

HPVs 6, 16, 18, 11, 31, and 51 were the most common genotypes. The prevalence rate of multiple HPV genotypes was 46.0% to 10.1%. Analysis of JAK2 V617F (1849 G > T) showed that prevalence of mutation was GG (65.1%), GA (34.9%), and TT (0%), respectively. There were no statistically significant differences between this mutation and variables of population survey (P ≥ 0.05).

Conclusions

The molecular epidemiology study on the genetic polymorphisms, i.e., JAK2 V617F and other single nucleotide polymorphisms as a diagnostic tool is necessary for cancer screening and prophylactic programs.

ANOVA model for network meta-analysis of diagnostic test accuracy data

Procedures combining and summarising direct and indirect evidence from independent studies assessing the diagnostic accuracy of different tests for the same disease are referred to network meta-analysis. Network meta-analysis provides a unified inference framework and uses the data more efficiently. Nonetheless, handling the inherent correlation between sensitivity and specificity continues to be a statistical challenge. We developed an arm-based hierarchical model which expresses the logit transformed sensitivity and specificity as the sum of fixed effects for test, correlated study-effects to model the inherent correlation between sensitivity and specificity and a random error associated with various tests evaluated in a given study. We present the accuracy of 11 tests used to triage women with minor cervical lesions to detect cervical precancer. Finally, we compare the results with those from a contrast-based model which expresses the linear predictor as a contrast to a comparator test. The proposed arm-based model is more appealing than the contrast-based model since the former permits more straightforward interpretation of the parameters, makes use of all available data yielding shorter credible intervals, and models more natural variance–covariance matrix structures.

Host chemokine signature as a biomarker for the detection of pre-cancerous cervical lesions

Background

The ability to distinguish which hrHPV infections predispose to significant disease is ever more pressing as a result of the increasing move to hrHPV testing for primary cervical screening. A risk-stratifier or “triage” of infection should ideally be objective and suitable for automation given the scale of screening.

Results

CCL2, CCL3, CCL4, CXCL1, CXCL8 and CXCL12 emerged as the strongest, candidate biomarkers to detect underlying disease [cervical intraepithelial neoplasia grade 2 or worse (CIN2+)]. For CIN2+, CCL2 had the highest area under the curve (AUC) of 0.722 with a specificity of 82%. A combined biomarker panel of six chemokines CCL2, CCL3, CCL4, CXCL1, CXCL8, and CXCL12 provides a sensitivity of 71% and specificity of 67%.

Conclusion

The present work demonstrates that the levels of five chemokine-proteins are indicative of underlying disease. We demonstrate technical feasibility and promising clinical performance of a chemokine-based biomarker panel, equivalent to that of other triage options. Further assessment in longitudinal series is now warranted.

Methods

A panel of 31 chemokines were investigated for expression in routinely taken archived and prospective cervical liquid based cytology (LBC) samples using Human Chemokine Proteomic Array kit. Nine chemokines were further validated using Procartaplex assay on the Luminex platform.

Cervical Cytology Biobanking in Europe

A cervical cytology biobank (CCB) is an extension of current cytopathology laboratory practice consisting in the systematic storage of Pap smears or liquid-based cytology samples from women participating in cervical cancer screening with the explicit purpose to facilitate future scientific research and quality audit of preventive services. A CCB should use an internationally agreed uniform cytology terminology, be integrated in a national or regional screening registry, and be linked to other registries (histology, cancer, vaccination). Legal and ethical principles concerning personal integrity and data safety must be respected strictly. Biobank-based studies require approval of ethical review boards.

A CCB is an almost inexhaustible resource for fundamental and applied biological research. In particular, it can contribute to answering questions on the natural history of HPV infection and HPV-induced lesions and cancers, screening effectiveness, exploration of new biomarkers, and surveillance of the short- and long-term effects of the introduction of HPV vaccination. To understand the limitations of CCB, more studies are needed on the quality of samples in relation to sample type, storage procedures, and duration of storage.

Biospecimens and Biobanking in Global Health

Biobanks provide a critical infrastructure to support research in human health. Biospecimens and their accompanying data are increasingly needed to support biomedical research and clinical care. The original text was initially published in the Handbook for Cancer Research in Africa. The value of this publication is great as it underlines the importance of biobanks in Africa as a key resource to increase quality scientific research and participate in global health research. Therefore, a revision to extend these principles to other low resource contexts, to include updated material and references and add the topic of biobank sustainability were relevant.

Prevalence of human papillomavirus infection and genotyping for population-based cervical screening in developed regions in China

We conducted a cross-sectional analysis to assess the distribution of human papillomavirus (HPV) types and explored an acceptable strategy for cervical screening in Shenzhen, China. A total of 2717 individuals ranging in age from 30–59 years were recruited. Clinical sensitivity and specificity as well as positive (PPV) and negative (NPV) predictive values were estimated. A triage strategy was regarded as acceptable when the NPV was at least 98.0%. 432 (15.9%) participants presented HPV positive. The five most prevalent HPV types were HPV52 (22.9%), HPV16 (12.7%), HPV53 (10.0%), HPV51 (8.6%), and HPV58 (8.1%). The CIN2+ risks for each HPV type were 40.0% for HPV33, 32.4% for HPV16, 18.2% for HPV58, 13.3% for HPV56, and 11.1% for HPV68 in descending order. Baseline cytology testing combined with HPV16/33/52/58 genotyping met the NPV thresholds at 98.6% with a PPV of 17.9%, demonstrating excellent clinical performance for detecting HPV types in CIN2+ patients. In conclusion, triaging HPV-positive women by baseline cytology combined with HPV16/58/33/52 genotyping is an acceptable strategy for cervical cancer screening in Shenzhen, China.

Cytology versus HPV testing for cervical cancer screening in the general population

BACKGROUND

Cervical cancer screening has traditionally been based on cervical cytology. Given the aetiological relationship between human papillomavirus (HPV) infection and cervical carcinogenesis, HPV testing has been proposed as an alternative screening test.

OBJECTIVES

To determine the diagnostic accuracy of HPV testing for detecting histologically confirmed cervical intraepithelial neoplasias (CIN) of grade 2 or worse (CIN 2+), including adenocarcinoma in situ, in women participating in primary cervical cancer screening; and how it compares to the accuracy of cytological testing (liquid-based and conventional) at various thresholds.

SEARCH METHODS

We performed a systematic literature search of articles in MEDLINE and Embase (1992 to November 2015) containing quantitative data and handsearched the reference lists of retrieved articles.

SELECTION CRITERIA

We included comparative test accuracy studies if all women received both HPV testing and cervical cytology followed by verification of the disease status with the reference standard, if positive for at least one screening test. The studies had to include women participating in a cervical cancer screening programme who were not being followed up for previous cytological abnormalities.

DATA COLLECTION AND ANALYSIS

We completed a 2 x 2 table with the number of true positives (TP), false positives (FP), true negatives (TN), and false negatives for each screening test (HPV test and cytology) used in each study. We calculated the absolute and relative sensitivities and the specificities of the tests for the detection of CIN 2+ and CIN 3+ at various thresholds and computed sensitivity (TP/(TP + TN) and specificity (TN/ (TN + FP) for each test separately. Relative sensitivity and specificity of one test compared to another test were defined as sensitivity of test-1 over sensitivity of test-2 and specificity of test-1 over specificity of test-2, respectively. To assess bias in the studies, we used the Quality Assessment of Diagnostic test Accuracy Studies (QUADAS) tool. We used a bivariate random-effects model for computing pooled accuracy estimates. This model takes into account the within- and between-study variability and the intrinsic correlation between sensitivity and specificity.

MAIN RESULTS

We included a total of 40 studies in the review, with more than 140,000 women aged between 20 and 70 years old. Many studies were at low risk of bias. There were a sufficient number of included studies with adequate methodology to perform the following test comparisons: hybrid capture 2 (HC2) (1 pg/mL threshold) versus conventional cytology (CC) (atypical squamous cells of undetermined significance (ASCUS)+ and low-grade squamous intraepithelial lesions (LSIL)+ thresholds) or liquid-based cytology (LBC) (ASCUS+ and LSIL+ thresholds), other high-risk HPV tests versus conventional cytology (ASCUS+ and LSIL+ thresholds) or LBC (ASCUS+ and LSIL+ thresholds). For CIN 2+, pooled sensitivity estimates for HC2, CC and LBC (ASCUS+) were 89.9%, 62.5% and 72.9%, respectively, and pooled specificity estimates were 89.9%, 96.6%, and 90.3%, respectively. The results did not differ by age of women (less than or greater than 30 years old), or in studies with verification bias. Accuracy of HC2 was, however, greater in European countries compared to other countries. The results for the sensitivity of the tests were heterogeneous ranging from 52% to 94% for LBC, and 61% to 100% for HC2. Overall, the quality of the evidence for the sensitivity of the tests was moderate, and high for the specificity.The relative sensitivity of HC2 versus CC for CIN 2+ was 1.52 (95% CI: 1.24 to 1.86) and the relative specificity 0.94 (95% CI: 0.92 to 0.96), and versus LBC for CIN 2+ was 1.18 (95% CI: 1.10 to 1.26) and the relative specificity 0.96 (95% CI: 0.95 to 0.97). The relative sensitivity of HC2 versus CC for CIN 3+ was 1.46 (95% CI: 1.12 to 1.91) and the relative specificity 0.95 (95% CI: 0.93 to 0.97). The relative sensitivity of HC2 versus LBC for CIN 3+ was 1.17 (95% CI: 1.07 to 1.28) and the relative specificity 0.96 (95% CI: 0.95 to 0.97).

AUTHORS' CONCLUSIONS

Whilst HPV tests are less likely to miss cases of CIN 2+ and CIN 3+, these tests do lead to more unnecessary referrals. However, a negative HPV test is more reassuring than a negative cytological test, as the cytological test has a greater chance of being falsely negative, which could lead to delays in receiving the appropriate treatment. Evidence from prospective longitudinal studies is needed to establish the relative clinical implications of these tests.

Analytic and Diagnostic Performances of Human Papillomavirus E6/E7 mRNA Test on up-to 11-Year-Old Liquid-Based Cervical Samples. A Biobank-Based Longitudinal Study

Human Papillomavirus (HPV) E6/E7 mRNA test demonstrated high specificity in detecting HPV infections, but studies assessing its efficacy in terms of cancer risk stratification are lacking. Follow-up studies are arduous and expensive. Biobank would be the answer to the problem, although data investigating the effects of long-term storage on RNA preservation are still needed. We addressed these issues by retrieving 202 residual liquid-based cervical specimens, collected from 149 women attending cervical cancer screening during the years 2001–2012. Samples were stored in Adriatic Biobank at room temperature and without any handing. After calculation of RNA yield and purity, E6/E7 mRNA test was retrospectively performed on each samples, to assess analytic and diagnostic performances. Using automated extraction procedures, RNA of good quantity and quality was obtained. The mean value of RNA concentration was 27.5 ng/μL. The mean A260/A280 ratio was 2.1. An invalid mRNA test result was found in 11.9% of the specimens. Neither RNA integrity, nor analytic performances of mRNA test were influenced by the year of sample collection. In total, 62.4% of the specimens tested as mRNA positive; among these, 89.2% were CIN2+. E6/E7 mRNA was detected in all Squamous Cervical Cancer (SCC) cases. Percentage of positive samples increased with the severity of histological diagnosis. mRNA testing, showing specificity and predictive values of 75.6% and 84.4%, respectively, significantly improved the corresponding values for DNA testing. Thus, the reflex mRNA test was demonstrated to be suitable to triage women with persistent cervical lesions. A “one sample for all” approach is possible, with practical benefits for Biobank-based long-term longitudinal studies, diseases prevention, prediction, diagnosis and treatment.

First-void urine: A potential biomarker source for triage of high-risk human papillomavirus infected women

Great interest has been directed towards the use of first-void urine as a liquid biopsy for high-risk human papillomavirus DNA testing. Despite the high correlations established between urinary and cervical infections, human papillomavirus testing is unable to distinguish between productive and transforming high-risk infections that have the tendency to progress to cervical cancer. Thus far, investigations have been primarily confined to the identification of biomarkers for triage of high-risk human papillomavirus-positive women in cervicovaginal specimens and tissue biopsies. This paper reviews urinary biomarkers for cervical cancer and triage of high-risk human papillomavirus infections and elaborates on the opportunities and challenges that have emerged regarding the use of first-void urine as a liquid biopsy for the analysis of both morphological- (conventional cytology and novel immunohistochemical techniques) and molecular-based (HPV16/18 genotyping, host/viral gene methylation, RNA, and proteins) biomarkers. A literature search was performed in PubMed and Web of Science for studies investigating the use of urine as a biomarker source for cervical cancer screening. Five studies were identified reporting on biomarkers that are still in preclinical exploratory or clinical assay development phases and on assessments of non-invasive (urine) samples. Although large-scale validation studies are still needed, we conclude that methylation of both host and viral genes in urine has been proven feasible for use as a molecular cervical cancer triage and screening biomarker in phase two studies. This is especially promising and underscores our hypothesis that human papillomavirus DNA and candidate human and viral biomarkers are washed away with the initial, first-void urine, together with exfoliated cells, debris and impurities that line the urethra opening. Similar to the limitations of self-collected cervicovaginal samples, first-void urine will likely not fulfil the high-quality cellularity standards required for morphological biomarkers. Molecular biomarkers will likely overcome this issue to yield high-throughput, objective, and reproducible results. When using proper sampling, transport, storage, preanalytical biomarker concentration techniques, and clinically validated assays, first-void urine is expected to be a valuable source of molecular biomarkers for cervical cancer screening. Furthermore, as first-void urine can be easily and non-invasively collected, it is a highly preferred technique among women and offers the ability to test both primary high-risk human papillomavirus and biomarkers in the same sample. In addition, the use of first-void urine confers opportunities to reduce loss-to follow-up and non-adherence to screening subjects.

Molecular tests potentially improving HPV screening and genotyping for cervical cancer prevention

INTRODUCTION

Human papillomavirus (HPV)-related cancers can be averted by type-specific vaccination (primary prevention) and/or through detection and ablation of precancerous cervical lesions (secondary prevention). This review presents current challenges to cervical cancer screening programs, focusing on recent molecular advances in HPV testing and potential improvements on risk stratification. Areas covered: High-risk (HR)-HPV DNA detection has been progressively incorporated into cervix cancer prevention programs based on its increased sensitivity. Advances in next-generation sequencing (NGS) are being rapidly applied to HPV typing. However, current HPV DNA tests lack specificity for identification of cervical precancer (CIN3). HPV typing methods were reviewed based on published literature, with a focus on these applications for screening and risk stratification in the emerging complex clinical scenario post-vaccine introduction. In addition, the potential for NGS technologies to increase specificity is discussed in regards to reflex testing of specimens for emerging biomarkers for cervix precancer/cancer. Expert commentary: Integrative multi-disciplinary molecular tests accurately triaging exfoliated cervical specimens will improve cervical cancer prevention programs while simplifying healthcare procedures in HPV-infected women. Hence, the concept of a 'liquid-biopsy' (i.e., 'molecular' Pap test) highly specific for early identification of cervical precancerous lesions is of critical importance in the years to come.

Interobserver reproducibility of cytologic p16INK4a /Ki-67 dual immunostaining in human papillomavirus-positive women

BACKGROUND

The accumulation of cyclin-dependent kinase inhibitor 2A (p16^ink4a ) protein in a cell is associated with neoplastic progression in precancerous cervical lesions. Dual staining for p16^ink4a and Ki-67 has been proposed as a triage test in cervical cancer screening for women who test positive for human papillomavirus DNA. In this study, interobserver reproducibility of the interpretation of this test was assessed.

METHODS

Forty-two immunostained, liquid-based cytology slides were divided into 2 sets and were interpreted by 17 to 21 readers from 9 different laboratories, yielding a total of 816 reports. Immunostaining results were classified as positive, negative, inconclusive, or inadequate. After evaluation of the first set of slides and before circulation of the second set, the results were discussed in a plenary meeting. The 10 slides with the most discordant results were evaluated again by selected expert cytopathologists.

RESULTS

The overall κ value was 0.612 (95% confidence interval [CI], 0.523-0.701), it was higher for the positive and negative categories (κ = 0.692 and κ = 0.641, respectively), and it was almost null for the inconclusive category (κ = 0.058). Considering only readers from laboratories with documented experience, the κ value was higher (κ = 0.747; 95% CI, 0.643-0.839) compared with nonexperienced centers (κ = 0.498; 95% CI, 0.388-0.616). The results were similar in both sets of slides (κ = 0.505 [95% CI, 0.358-0.642] and κ = 0.521 [95% CI, 0.240-0.698] for the first and second sets, respectively). Reinterpretation of the slides with the most discordant results did not provide any improvement (first evaluation, κ = 0.616 [95% CI, 0.384-0.866]; second evaluation, κ = 0.403 [95% CI, 0.182-0.643]).

CONCLUSIONS

Dual staining for p16 ^ink4a and Ki-67 demonstrated good reproducibility, confirming its robustness, which is a necessary prerequisite for its adoption as a triage test in cervical cancer screening programs that use human papillomavirus DNA as a primary test. Cancer Cytopathol 2017;125:212-220. © 2016 American Cancer Society.

p16/Ki-67 co-expression associates high risk human papillomavirus persistence and cervical histopathology: a 3-year cohort study in China

PURPOSE

To evaluate the association of p16/Ki-67 co-expression and persistence of high-risk human papillomavirus (HR-HPV) infection as well as cervical abnormalities.

METHODS

We performed a 3-year cohort study among which 2498 Chinese women aged 25 to 65 years were screened by different HPV tests in 2011. 690 women who were positive at any of the tests and a random sample of 164 women with all negative results received colposcopy, cervical specimens for cobas HPV test (Roche diagnostics) were collected before colposcopy; of this group, 737 cervical specimens were collected to perform cobas, Liquid-based cytology, HPV E6 test (Arbor Vita Corporation) and p16/Ki-67 dual staining (Roche diagnostics) in 2014. Colposcopy and biopsies was performed on women with any abnormal result.

RESULTS

Compared to women without HR-HPV persistent infection, women in the HR-HPV persistence group had a higher risk of p16/Ki-67 positive, with an adjusted Odds Ratio(OR) and 95% confidence interval (CI) of 6.29 (4.07-9.72); moreover, adjusted odds ratio for women who had HPV16/18 persistent infection was nearly 4-folder higher than women with other 12 HR-HPV persistent infection (adjusted OR = 17.15, 95% CI: 7.11-41.33 vs adjusted OR = 4.68, 95% CI: 2.89-7.58). Additionally, p16/Ki-67 positivity rate significantly increased with the severity of the cytological and histological abnormalities, and resulted strongly associated with a CIN2+ diagnosis (OR = 16.03, 95% CI: 4.46-57.59).

CONCLUSIONS

p16/Ki-67 co-expressions associated strongly with HR-HPV persistence, especially with HPV16/18, and the presence of a CIN2+ lesion. Therefore, p16/Ki-67 could be considered as a suitable biomarker for cervical cancer screening, particularly in HPV-based screening programs.

The Value of a Novel Panel of Cervical Cancer Biomarkers for Triage of HPV Positive Patients and for Detecting Disease Progression

In the era of primary vaccination against HPV and at the beginning of the low prevalence of cervical lesions, introduction of screening methods that can distinguish between low- and high-grade lesions is necessary in order to maintain the positive predictive value of screening. This case-control study included 562 women who attended cervical screening or were referred for colposcopy and 140 disease free controls, confirmed by histology and/or cytology. The cases were stratified by age. Using routine exfoliated liquid based cytological samples RT-PCR measurements of biomarker genes, high-risk HPV testing and liquid based cytology were performed and used to evaluate different testing protocols including sets of genes/tests with different test cut-offs for the diagnostic panels. Three new panels of cellular biomarkers for improved triage of hrHPV positive women (diagnostic panel) and for prognostic assessment of CIN lesions were proposed. The diagnostic panel (PIK3AP1, TP63 and DSG3) has the potential to distinguish cytologically normal hrHPV+ women from hrHPV+ women with CIN2+. The prognostic gene panels (KRT78, MUC5AC, BPIFB1 and CXCL13, TP63, DSG3) have the ability to differentiate hrHPV+ CIN1 and carcinoma cases. The diagnostic triage panel showed good likelihood ratios for all age groups. The panel showed age-unrelated performance and even better diagnostic value under age 30, a unique feature among the established cervical triage tests. The prognostic gene-panels demonstrated good discriminatory power and oncogenic, anti-oncogenic grouping of genes. The study highlights the potential for the gene expression panels to be used for diagnostic triage and lesion prognostics in cervical cancer screening.

Clinical validation of hrHPV testing on vaginal and urine self-samples in primary cervical screening (cross-sectional results from the Papillomavirus Dumfries and Galloway-PaVDaG study)

OBJECTIVES

Papillomavirus Dumfries and Galloway (PaVDaG) assessed the performance of a high-risk human papillomavirus (hrHPV) PCR-based assay to detect high-grade cervical intraepithelial neoplasia (CIN2+) in self-collected vaginal and urine samples.

SETTING

Women attending routine cervical screening in primary care.

PARTICIPANTS

5318 women aged 20-60 years provided self-collected random urine and vaginal samples for hrHPV testing and a clinician-collected liquid-based cytology (LBC) sample for cytology and hrHPV testing.

INTERVENTIONS

HrHPV testing. All samples were tested for hrHPV using the PCR-based cobas 4800 assay. Colposcopy was offered to women with high-grade or repeated borderline/low-grade cytological abnormalities; also to those who were LBC negative but hrHPV 16/18 positive.

PRIMARY AND SECONDARY OUTCOME MEASURES

The self-tests' absolute sensitivity and specificity for CIN2+ were assessed on all biospecimens; also, their relative sensitivity and specificity compared with clinician-taken samples. Interlaboratory and intralaboratory performance of the hrHPV assay in self-collected samples was also established.

RESULTS

HrHPV prevalence was 14.7%, 16.6% and 11.6% in cervical, vaginal and urine samples, respectively. Sensitivity for detecting CIN2+ was 97.7% (95% to 100%), 94.6% (90.7% to 98.5%) and 63.1% (54.6% to 71.7%) for cervical, vaginal and urine hrHPV detection, respectively. The corresponding specificities were 87.3% (86.4% to 88.2%), 85.4% (84.4% to 86.3%) and 89.8% (89.0% to 90.7%). There was a 38% (24% to 57%) higher HPV detection rate in vaginal self-samples from women over 50 years compared with those ≤29 years. Relative sensitivity and specificity of hrHPV positivity for the detection of CIN2+ in vaginal versus cervical samples were 0.97 (0.94 to 1.00) and 0.98 (0.97 to 0.99); urine versus cervical comparisons were 0.53 (0.42 to 0.67) and 1.03 (1.02 to 1.04). The intralaboratory and interlaboratory agreement for hrHPV positivity in self-samples was high (κ values 0.98 (0.96 to 0.99) and 0.94 (0.92 to 0.97) for vaginal samples and 0.95 (0.93 to 0.98) and 0.90 (0.87 to 0.94) for urine samples).

CONCLUSIONS

The sensitivity of self-collected vaginal samples for the detection of CIN2+ was similar to that of cervical samples and justifies consideration of this sample for primary screening.

VALGENT: A protocol for clinical validation of human papillomavirus assays

BACKGROUND

Testing for high-risk HPV is more effective in primary cervical cancer screening than the cytological examination of a Pap smear. Separate genotyping may be useful for triage in both HPV-based and cytology-based screening. Only clinically validated tests should be used in clinical practice.

OBJECTIVES

VALGENT is a study framework for test comparison and validation of HPV assays in general and HPV genotyping tests in particular according to clinically relevant outcomes and for clinical applications endorsed by scientific evidence.

STUDY DESIGN

VALGENT involves the collation of fresh or archived cervical cell specimen from women attending routine screening supplemented with cytologically abnormal samples. Multiple aliquots of residual material are sent from a central laboratory to participating laboratories for testing with novel HPV assays with limited, extended or full genotyping capacity. Outcomes are derived from screening and pathology registries. Each VALGENT panel includes an assay already validated for screening. A series of accuracy and concordance statistics were generated.

RESULTS

Currently, two VALGENT study rounds, originated from laboratories in Antwerp (Belgium) and Edinburgh (Scotland), were completed. Two new assays (G5+/6+ PCR-LMNX and Xpert HPV) were validated for screening by showing similar accuracy for cervical precancer as the standard comparator test. For two other tests (BD Onclarity, PapilloCheck) validation was confirmed. Inter-test agreement was high although certain type-specific discordances were observed which warrant further analysis.

CONCLUSION

VALGENT extends current guidelines for high-risk HPV test validation in cervical cancer screening and has produced a large study resource for test comparison. More robust procedures of sample selection and handling and integration with the global WHO reference laboratory network focusing on analytical accuracy, may result in the generation of an international standard and a formalized system for clinical validation of HPV assays and quality control in HPV-based screening.

Triage of HPV positive women in cervical cancer screening

Despite HPV vaccines, screening will remain central for decades to control cervical cancer. Recently, HPV testing alone or with cytology was introduced as an alternative to cytology screening. However, most HPV infections are harmless and additional tests are required to identify women with progressing infections or precancer. With three options for primary screening, and without clear strategies for triage of screen-positive women, there is great confusion about the best approach. Also, increasing HPV vaccination coverage will lead to lower disease prevalence, and force new screening approaches. Currently recommended triage strategies for primary HPV screening include HPV genotyping for HPV16 and HPV18 and cytology. Other alternatives that are currently evaluated include p16/Ki-67 dual stain cytology, host methylation, and viral methylation testing. Clinical management of women with cervical cancer screening results is moving to use risk thresholds rather than individual test results. Specific risk thresholds have been defined for return to primary screening, repeat testing, referral to colposcopy, and immediate treatment. Choice of test algorithms is based on comparison of absolute risk estimates from triage tests with established clinical thresholds. Importantly, triage tests need to be evaluated together with the primary screening test and the downstream clinical management. An optimal integrated screening and triage strategy should reassure the vast majority of women that they are at very low risk of cervical cancer, send the women at highest risk to colposcopy at the right time, when disease can be colposcopically detected, and minimize the intermediate risk group that requires continued surveillance.

Commercially available molecular tests for human papillomaviruses (HPV): 2015 update

Commercial molecular tests for human papillomaviruses (HPV) are invaluable diagnostic tools in cervical carcinoma screening and management of women with cervical precancerous lesions as well as important research tools for epidemiological studies, vaccine development, and implementation and monitoring of vaccination programs. In this third inventory of commercial HPV tests, we identified 193 distinct commercial HPV tests and at least 127 test variants available on the market in 2015, which represents a 54% and 79% increase in the number of distinct HPV tests and variants, respectively, in comparison to our last inventory performed in 2012. Identified HPV tests were provisionally divided into eight main groups and several subgroups. Among the 193 commercial HPV tests, all but two target alpha-HPV types only. Although the number of commercial HPV tests with at least one published study in peer-reviewed literature has increased significantly in the last three years, several published performance evaluations are still not in line with agreed-upon standards in the HPV community. Manufacturers should invest greater effort into evaluating their products and publishing validation/evaluation results in peer-reviewed journals. To achieve this, more clinically oriented external quality-control panels and initiatives are required. For evaluating the analytical performance of the entire range of HPV tests currently on the market, more diverse and reliable external quality-control programs based on international standards for all important HPV types are indispensable. The performance of a wider range of HPV tests must be promptly evaluated on a variety of alternative clinical specimens. In addition, more complete HPV assays containing validated sample-extraction protocols and appropriate internal controls are urgently needed. Provision of a broader range of automated systems allowing large-scale HPV testing as well as the development of reliable, rapid, and affordable molecular point-of-care tests are priorities for the further improvement of HPV tests.

The predictive value of human papillomavirus testing for the outcome of patients conservatively treated for stage IA squamous cell cervical carcinoma

BACKGROUND

Although it is hypothesised that human papillomavirus (HPV) testing may have a role in surveillance of patients conservatively treated for stage IA squamous cell cervical carcinoma, research on this topic has been minimal.

OBJECTIVES

To determine: (1) the changes in HPV test result from treatment onward; (2) the time to viral clearance; and (3) the negative predictive value (NPV) and positive predictive value (PPV) of HPV test result for the detection of CIN2 or worse (CIN2+) during follow-up.

STUDY DESIGN

In a multicentre retrospective follow-up study of a consecutive series (1997-2009) of 91 patients, longitudinal outcome measures were estimated as cumulative probabilities using the Kaplan-Meier method.

RESULTS

For patients testing HPV-positive at the first follow-up visit (n=44), the probability of change to negative rose from 0 to 0.78 between 7 and 21 months after treatment. For HPV-negative patients (n=47), the probability of change to positive rose to 0.13 between 9 and 26 months. After a median follow-up of 50 months (range, 2-80), the NPV for CIN2+ was 1.00. The PPV was 0.60 (95% confidence interval, 0.43-0.77) after 26 months. The median time to detection was 5 months.

CONCLUSIONS

If adequately confirmed, these findings would indicate that HPV testing is capable to identify the patients who have had their lesions fully removed, and would make it possible to focus follow-up efforts on a subset of patients at high risk of residual or progressive disease.

Clinical application of DNA ploidy to cervical cancer screening: A review

Screening for cervical cancer with DNA ploidy assessment by automated quantitative image cytometry has spread throughout China over the past decade and now an estimated 1 million tests per year are done there. Compared to conventional liquid based cytology, DNA ploidy has competitive accuracy with much higher throughput per technician. DNA ploidy has the enormous advantage that it is an objective technology that can be taught in typically 2 or 3 wk, unlike qualitative cytology, and so it can enable screening in places that lack sufficient qualified cytotechnologists and cytopathologists for conventional cytology. Most papers on experience with application of the technology to cervical cancer screening over the past decade were published in the Chinese language. This review aims to provide a consistent framework for analysis of screening data and to summarize some of the work published from 2005 to the end of 2013. Of particular interest are a few studies comparing DNA ploidy with testing for high risk human papilloma virus (hrHPV) which suggest that DNA ploidy is at least equivalent, easier and less expensive than hrHPV testing. There may also be patient management benefits to combining hrHPV testing with DNA ploidy. Some knowledge gaps are identified and some suggestions are made for future research directions.

Performance of self-collected cervical samples in screening for future precancer using human papillomavirus DNA testing

BACKGROUND

Self-collected human papillomavirus (HPV) testing could reduce barriers to cervical cancer screening, with performance comparable to clinician-collected specimens. The ability of self-collected specimens to cross-sectionally and prospectively detect precursor lesions was investigated in an HPV vaccine randomized trial in Costa Rica.

METHODS

In the trial, 7466 women age 18 to 25 years received an HPV16/18 or control vaccine and were followed at least annually for four years. In this secondary analysis, we included all women who provided a self-collected cervicovaginal specimen six months after enrollment (5109 women = full analytical cohort). A subset (615 women = restricted cohort) also had clinician-collected specimens at the six-month postenrollment visit. High-grade squamous intraepithelial lesion or repeat low-grade squamous intraepithelial lesion prompted colposcopic referral throughout the study. HPV testing was performed with SPF10PCR/DEIA/LiPA25. Cross-sectional and prospective sensitivity, specificity, and predictive values were estimated.

RESULTS

In the full cohort, one-time HPV testing on self-collected samples detected prevalent CIN2+ with a sensitivity of 88.7% (95% confidence interval [CI] =77.0% to 95.7%) and a specificity of 68.9% (95% CI = 67.6% to 70.1%). For predicting incident CIN2+ in the subsequent four years, sensitivity was 73.9% (95% CI = 65.8% to 81.0%) and specificity 69.4% (95% CI = 68.1% to 70.7%). In the restricted cohort, for incident CIN2+, self-collected HPV was much more sensitive than cytology (80.0% vs 10.0%); relative sensitivity was 0.1 (95% CI = 0.03% to 0.5%). Furthermore, three times more women with normal baseline cytology developed incident CIN2+ than those with negative self-collected HPV. Self-collected and clinician-collected HPV testing had comparable performance. Agreement between self- and clinician-collected samples was 89.7% (kappa = 0.78, McNemar χ2 = 0.62) for carcinogenic HPV types.

CONCLUSIONS

Self-collected specimens can be used for HPV-based screening, providing sensitivity and specificity comparable with clinician-collected specimens and detecting disease earlier than cytology.

Effectiveness of two strategies to follow-up ASC-US and LSIL screening results in The Netherlands using repeat cytology with or without additional hrHPV testing: a retrospective cohort study

PURPOSE

The purpose of the study was to assess the effectiveness of repeat cytology with and without additional high-risk human papilloma virus (hrHPV) testing after atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesion (ASC-US/LSIL) screening results.

METHODS

In the Netherlands, ASC-US/LSIL is triaged by repeat cytology at 6 months or repeat cytology at 6 months with additional hrHPV testing. ASC-US/LSIL results from 13,734 screenees in 2008 were extracted from "Dutch Pathology Registry" including cytology, histology, and/or HPV follow-up results. Proportions of compliance, repeat cytology, referral, and detected cervical intraepithelial neoplasia (CIN) were assessed.

RESULTS

With additional hrHPV testing, 46.8 % was send back to regular screening at 6 months, 28.6 % needed second repeat cytology, and 24.6 % was referred for colposcopy. Without additional hrHPV testing, this was 0.0, 76.1, and 23.9 %, respectively. With additional hrHPV testing, significantly higher proportions of persisting ASC-US/LSIL; compliance with repeat/referral advices; and histological detection of CIN0 (no CIN or cancer), CIN1, and CIN2 were found but equal proportions CIN3+.

CONCLUSIONS

Additional hrHPV testing shortens follow-up without altering CIN3+ detection. Detection of CIN0, CIN1, and CIN2 was higher, presumably by hrHPV-driven biased cytology and detection bias. Restricting additional hrHPV testing to older women, reading cytology without knowledge of hrHPV status, and addition of more specific triage tests could further improve the effectiveness of additional hrHPV testing.

Clinical implications of (epi)genetic changes in HPV-induced cervical precancerous lesions

Infection of cervical epithelium with high-risk human papilloma virus (hrHPV) might result in productive or transforming cervical intraepithelial neoplasia (CIN) lesions, the morphology of which can overlap. In transforming CIN lesions, aberrations in host cell genes accumulate over time, which is necessary for the ultimate progression to cancer. On the basis of (epi)genetic changes, early and advanced transforming CIN lesions can be distinguished. This paves the way for new molecular tools for cervical screening, diagnosis and management of cervical cancer precursor lesions.

Accuracy of human papillomavirus testing on self-collected versus clinician-collected samples: a meta-analysis

BACKGROUND

Screening for human papillomavirus (HPV) infection is more effective in reducing the incidence of cervical cancer than screening using Pap smears. Moreover, HPV testing can be done on a vaginal sample self-taken by a woman, which offers an opportunity to improve screening coverage. However, the clinical accuracy of HPV testing on self-samples is not well-known. We assessed whether HPV testing on self-collected samples is equivalent to HPV testing on samples collected by clinicians.

METHODS

We identified relevant studies through a search of PubMed, Embase, and CENTRAL. Studies were eligible for inclusion if they fulfilled all of the following selection criteria: a cervical cell sample was self-collected by a woman followed by a sample taken by a clinician; a high-risk HPV test was done on the self-sample (index test) and HPV-testing or cytological interpretation was done on the specimen collected by the clinician (comparator tests); and the presence or absence of cervical intraepithelial neoplasia grade 2 (CIN2) or worse was verified by colposcopy and biopsy in all enrolled women or in women with one or more positive tests. The absolute accuracy for finding CIN2 or worse, or CIN grade 3 (CIN3) or worse of the index and comparator tests as well as the relative accuracy of the index versus the comparator tests were pooled using bivariate normal models and random effect models.

FINDINGS

We included data from 36 studies, which altogether enrolled 154 556 women. The absolute accuracy varied by clinical setting. In the context of screening, HPV testing on self-samples detected, on average, 76% (95% CI 69-82) of CIN2 or worse and 84% (72-92) of CIN3 or worse. The pooled absolute specificity to exclude CIN2 or worse was 86% (83-89) and 87% (84-90) to exclude CIN3 or worse. The variation of the relative accuracy of HPV testing on self-samples compared with tests on clinician-taken samples was low across settings, enabling pooling of the relative accuracy over all studies. The pooled sensitivity of HPV testing on self-samples was lower than HPV testing on a clinician-taken sample (ratio 0·88 [95% CI 0·85-0·91] for CIN2 or worse and 0·89 [0·83-0·96] for CIN3 or worse). Also specificity was lower in self-samples versus clinician-taken samples (ratio 0·96 [0·95-0·97] for CIN2 or worse and 0·96 [0·93-0·99] for CIN3 or worse). HPV testing with signal-based assays on self-samples was less sensitive and specific than testing on clinician-based samples. By contrast, some PCR-based HPV tests generally showed similar sensitivity on both self-samples and clinician-based samples.

INTERPRETATION

In screening programmes using signal-based assays, sampling by a clinician should be recommended. However, HPV testing on a self-sample can be suggested as an additional strategy to reach women not participating in the regular screening programme. Some PCR-based HPV tests could be considered for routine screening after careful piloting assessing feasibility, logistics, population compliance, and costs.

FUNDING

The 7th Framework Programme of the European Commission, the Belgian Foundation against Cancer, the International Agency for Research on Cancer, and the German Guideline Program in Oncology.

Clinical impact of the analytical specificity of the hybrid capture 2 test: data from the New Technologies for Cervical Cancer (NTCC) study

The Hybrid Capture 2 (HC2) test targets 13 human papillomavirus (HPV) types. Here, cross-reactivity with non-HC2-targeted HPV types is described. We aimed to define the proportion of HC2-positive women who had negative results with HC2-targeted HPV types and estimate its determinants and impact on women's health management. The New Technologies for Cervical Cancer (NTCC) trial was followed in two predetermined phases. Women in the experimental arm were tested for the presence of HPV DNA by HC2 following a sample collection in PreservCyt (first phase) or Digene specimen transport medium (STM) (second phase). HPV genotyping was performed on DNA samples from HC2-positive women by PCR with GP5(+)/GP6(+) primers and reverse line blot (RLB) hybridization. Untyped samples were submitted to direct sequencing or restriction fragment length polymorphism. Multivariate logistic regression analysis estimated the adjusted odds ratios (ORs) between the presence of HC2-targeted types and age, viral load, and type of transport medium. Out of 2,920 HC2-positive samples, 2,310 (79.1%) were positive on RLB for HC2-targeted types, 396 were positive (13.6%) for only non-HC2-targeted types (mostly represented by HPV-53, HPV-66, and HPV-70), and in 214 (7.33%) samples, no HPV types were detected. The probability of detecting HC2-targeted types increased with increasing viral load expressed as the relative light unit/positive-control specimen ratio (RLU/PC) (OR for unitary increase of log RLU/PC, 1.35; 95% confidence interval [CI], 1.30 to 1.42) and with STM versus PreservCyt (OR, 1.56; 95% CI, 1.25 to 1.84). If only the samples containing HC2-targeted types tested positive, the positive predictive value (PPV) would have increased from 7.0% (95% CI, 6.1% to 8.0%) to 8.4% (95% CI, 7.3 to 9.6), although 4.9% (95% CI, 2.4% to 8.8%) of cervical intraepithelial neoplasia grade 2(+) (CIN2(+)) cases would have been missed. In conclusion, STM use and an increased cutoff would reduce the HC2 analytical false-positive rate and increase the positive predictive value for high-grade CIN. The gain in clinical sensitivity by detecting non-HC2-targeted HPV types is limited.

Nucleic acid tests for the detection of alpha human papillomaviruses

Testing for high-risk types of alpha human papillomaviruses (HPV) is an invaluable part of clinical guidelines for cervical carcinoma screening, management and treatment. In this comprehensive inventory of commercial tests for detection of alpha-HPV, we identified at least 125 distinct HPV tests and at least 84 variants of the original tests. However, only a small subset of HPV tests has documented clinical performance for any of the standard HPV testing indications. For more than 75% of HPV tests currently on the market, no single publication in peer-reviewed literature can be identified. HPV tests that have not been validated and lack proof of reliability, reproducibility and accuracy should not be used in clinical management. Once incorporated in the lab, it is essential that the whole procedure of HPV testing is subject to continuous and rigorous quality assurance to avoid sub-optimal, potentially harmful practices. Manufacturers of HPV tests are urged to put more effort into evaluating their current and future products analytically, using international standards, and for clinical applications, using clinically validated endpoints. To assist with analytical validation, the World Health Organization is developing international standards for HPV types other than HPV16 and HPV18 and is planning development of external quality control panels specifically designed to be used for performance evaluation of current and future HPV tests. There is a need for more competitively priced HPV tests, especially for resource-poor countries, and uniform test validation criteria based on international standards should enable issuing more competitive and fair tender notices for purchasing. Automation systems allowing large-scale testing, as well as further increases in clinical performance, are the main needs in the further improvement of HPV tests. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Human papillomavirus testing versus repeat cytology for triage of minor cytological cervical lesions

BACKGROUND

Atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intra-epithelial lesions (LSIL) are minor lesions of the cervical epithelium, detectable by cytological examination of cells collected from the surface of the cervix of a woman.Usually, women with ASCUS and LSIL do not have cervical (pre-) cancer, however a substantial proportion of them do have underlying high-grade cervical intra-epithelial neoplasia (CIN, grade 2 or 3) and so are at increased risk for developing cervical cancer. Therefore, accurate triage of women with ASCUS or LSIL is required to identify those who need further management.This review evaluates two ways to triage women with ASCUS or LSIL: repeating the cytological test, and DNA testing for high-risk types of the human papillomavirus (hrHPV) - the main causal factor of cervical cancer.

OBJECTIVES

Main objective To compare the accuracy of hrHPV testing with the Hybrid Capture 2 (HC2) assay against that of repeat cytology for detection of underlying cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) or grade 3 or worse (CIN3+) in women with ASCUS or LSIL. For the HC2 assay, a positive result was defined as proposed by the manufacturer. For repeat cytology, different cut-offs were used to define positivity: Atypical squamous cells of undetermined significance or worse (ASCUS+), low-grade squamous intra-epithelial lesions or worse (LSIL+) or high-grade squamous intra-epithelial lesions or worse (HSIL+).Secondary objective To assess the accuracy of the HC2 assay to detect CIN2+ or CIN3+ in women with ASCUS or LSIL in a larger group of reports of studies that applied hrHPV testing and the reference standard (coloscopy and biopsy), irrespective whether or not repeat cytology was done.

SEARCH METHODS

We made a comprehensive literature search that included the Cochrane Register of Diagnostic Test Accuracy Studies; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (through PubMed), and EMBASE (last search 6 January 2011). Selected journals likely to contain relevant papers were handsearched from 1992 to 2010 (December). We also searched CERVIX, the bibliographic database of the Unit of Cancer Epidemiology at the Scientific Institute of Public Health (Brussels, Belgium) which contains more than 20,000 references on cervical cancer.More recent searches, up to December 2012, targeted reports on the accuracy of triage of ASCUS or LSIL with other HPV DNA assays, or HPV RNA assays and other molecular markers. These searches will be used for new Cochrane reviews as well as for updates of the current review.

SELECTION CRITERIA

Studies eligible for inclusion in the review had to include: women presenting with a cervical cytology result of ASCUS or LSIL, who had undergone both HC2 testing and repeat cytology, or HC2 testing alone, and were subsequently subjected to reference standard verification with colposcopy and colposcopy-directed biopsies for histologic verification.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data from the selected studies, and obtained additional data from report authors.Two groups of meta-analyses were performed: group I concerned triage of women with ASCUS, group II concerned women with LSIL. The bivariate model (METADAS-macro in SAS) was used to assess the absolute accuracy of the triage tests in both groups as well as the differences in accuracy between the triage tests.

MAIN RESULTS

The pooled sensitivity of HC2 was significantly higher than that of repeat cytology at cut-off ASCUS+ to detect CIN2+ in both triage of ASCUS and LSIL (relative sensitivity of 1.27 (95% CI 1.16 to 1.39; P value < 0.0001) and 1.23 (95% CI 1.06 to 1.4; P value 0.007), respectively. In ASCUS triage, the pooled specificity of the triage methods did not differ significantly from each other (relative specificity: 0.99 (95% CI 0.97 to 1.03; P value 0.98)). However, the specificity of HC2 was substantially, and significantly, lower than that of repeat cytology in the triage of LSIL (relative specificity: 0.66 (95% CI 0.58 to 0.75) P value < 0.0001).

AUTHORS' CONCLUSIONS

HPV-triage with HC2 can be recommended to triage women with ASCUS because it has higher accuracy (significantly higher sensitivity, and similar specificity) than repeat cytology. When triaging women with LSIL, an HC2 test yields a significantly higher sensitivity, but a significantly lower specificity, compared to a repeat cytology. Therefore, practice recommendations for management of women with LSIL should be balanced, taking local circumstances into account.

A framework provided an outline toward the proper evaluation of potential screening strategies

OBJECTIVES

Screening tests are often introduced into clinical practice without proper evaluation, despite the increasing awareness that screening is a double-edged sword that can lead to either net benefits or harms. Our objective was to develop a comprehensive framework for the evaluation of new screening strategies.

STUDY DESIGN AND SETTING

Elaborating on the existing concepts proposed by experts, a stepwise framework is proposed to evaluate whether a potential screening test can be introduced as a screening strategy into clinical practice. The principle of screening strategy evaluation is illustrated for cervical cancer, which is a template for screening because of the existence of an easily detectable and treatable precursor lesion.

RESULTS

The evaluation procedure consists of six consecutive steps. In steps 1-4, the technical accuracy, place of the test in the screening pathway, diagnostic accuracy, and longitudinal sensitivity and specificity of the screening test are assessed. In steps 5 and 6, the impact of the screening strategy on the patient and population levels, respectively, is evaluated. The framework incorporates a harm and benefit trade-off and cost-effectiveness analysis.

CONCLUSION

Our framework provides an outline toward the proper evaluation of potential screening strategies before considering implementation.

HPV genotype distribution according to severity of cervical neoplasia using the Digene HPV genotyping LQ test

A new genotyping-based DNA assay (Digene LQ^®) was developed recently. The primary aim was to assess the distribution of HPV types using this new assay in atypical squamous cells of undeterminate significance (ASCUS). The secondary aim was to correlate the HPV types with the severity of the disease. The study population comprised 376 ASCUS women. The women were all Hybrid Capture II (HCII) positive and were admitted in three European referral gynecology clinics between 2007 and 2010. A colposcopy with histological examination was performed in all these patients. HPV 16 was typed in 40 % of patients, HPV 18 in 7 %, and HPV 31 in 17 %, and 18 % of patients had mixed genotypes. Patients aged over 30 more often had the HPV 16 genotype than patients aged under 30 (29 % vs. 11 %, chi-square test p < 0.001). The risk of cervical intra-epithelial neoplasia of grade 2 or more (CIN2 +) when HPV 18 positive is lower than the probability associated with HPV 16 or HPV 31: 28 % vs. 58 % and 52 %, respectively (chi-square test, p = 0.005 and p = 0.05, respectively). The Digene LQ^®, a new sequence-specific hybrid capture sample preparation, is fast and efficient and allows high-throughput genotyping of 18 HR HPV types by PCR compared to traditional non-sequence-specific sample preparation methods.

[Cervical cancer screening in Germany. Current status]

Cervical cancer screening was introduced in Germany 40 years ago and the incidence of cancer of the cervix has subsequently decreased by close to 70%. The remaining incidence of 5,600 cases per year represents only 2.8% of all newly occurring cases of cancer in women and these cases occur mainly in patients who do not participate in regular screening. Thus, cervical cancer screening by cytological smears has been proven to be successful. The structure of the German cancer screening program is characterized by decentralized organization, exclusive involvement of medical specialists such as gynecologists and pathologists and strict quality assurance. The recruitment is 50% on a yearly basis and the cumulative participation over 3 years reaches 79%. Since 2008 all laboratories are required to report complete data sets to local quality control agencies.The Joint Federal Committee in charge of evaluating new technologies in Germany mandated an inquiry into the possible role of screening by human papillomavirus (HPV) testing. According to this report published by the Institute for Quality Assurance and Efficiency in Healthcare there are indications for advantages. There are, however, no data in the literature as to possible disadvantages of HPV testing. A similar study for the US Preventive Services Task Force was published in May 2011 with almost identical conclusions.

Human papillomavirus genotyping, human papillomavirus mRNA expression, and p16/Ki-67 cytology to detect anal cancer precursors in HIV-infected MSM

OBJECTIVE

Anal cancer incidence is high in HIV-infected MSM. Screening for anal intraepithelial lesions and cancers is performed at specialized clinics and relies on high-resolution anoscopy (HRA) and anal cytology. Both approaches have limited reproducibility and sensitivity for detecting anal cancer precursors. We evaluated biomarkers for human papillomavirus (HPV)-related disease in a population of HIV-infected MSM.

METHODS

A cross-sectional screening study with passive follow-up included 363 MSM followed at a HIV/AIDS clinic. All men had anal cytology samples taken and were evaluated using HRA and anal biopsies. Using a composite endpoint of biopsy results and cytology, we compared the performance of HPV16/18 genotyping, HPVE6/E7 mRNA expression, and p16/Ki-67 cytology to detect high-grade anal intraepithelial neoplasias (AINs).

RESULTS

For all biomarkers analyzed, there was a significant trend of increasing percentage of men testing positive with increasing severity of disease (P < 0.001). HPV DNA testing had the highest sensitivity for anal intraepithelial neoplasia grade 2 and anal intraepithelial neoplasia grade 3 (AIN3), followed by p16/Ki-67, HPVE6/E7 mRNA testing, and HPV16/18 genotyping. The highest Youden's index was observed for HPVE6/E7 mRNA testing, followed by HPV16/18 genotyping, p16/Ki-67 cytology, and HPV DNA testing. Increasing the threshold for positivity of p16/Ki-67 to five or more positive cells led to significantly higher specificity, but unchanged sensitivity for detecting AIN3.

CONCLUSION

Molecular features of anal disease categories are similar to those of corresponding cervical lesions. Biomarkers evaluated for cervical cancer screening may be used for primary anal cancer screening or to decide who should require immediate treatment vs. expectant management.

Genome-wide methylation profiling identifies hypermethylated biomarkers in high-grade cervical intraepithelial neoplasia

Epigenetic modifications, such as aberrant DNA promoter methylation, are frequently observed in cervical cancer. Identification of hypermethylated regions allowing discrimination between normal cervical epithelium and high-grade cervical intraepithelial neoplasia (CIN2/3), or worse, may improve current cervical cancer population-based screening programs. In this study, the DNA methylome of high-grade CIN lesions was studied using genome-wide DNA methylation screening to identify potential biomarkers for early diagnosis of cervical neoplasia. Methylated DNA Immunoprecipitation (MeDIP) combined with DNA microarray was used to compare DNA methylation profiles of epithelial cells derived from high-grade CIN lesions with normal cervical epithelium. Hypermethylated differentially methylated regions (DMRs) were identified. Validation of nine selected DMRs using BSP and MSP in cervical tissue revealed methylation in 63.2-94.7% high-grade CIN and in 59.3-100% cervical carcinomas. QMSP for the two most significant high-grade CIN-specific methylation markers was conducted exploring test performance in a large series of cervical scrapings. Frequency and relative level of methylation were significantly different between normal and cancer samples. Clinical validation of both markers in cervical scrapings from patients with an abnormal cervical smear confirmed that frequency and relative level of methylation were related with increasing severity of the underlying CIN lesion and that ROC analysis was discriminative. These markers represent the COL25A1 and KATNAL2 and their observed increased methylation upon progression could intimate the regulatory role in carcinogenesis. In conclusion, our newly identified hypermethylated DMRs represent specific DNA methylation patterns in high-grade CIN lesions and are candidate biomarkers for early detection.