Hybrid Capture 2 and cobas human papillomavirus assays perform similarly on SurePath samples from women with abnormalities

Validation of cobas 4800 HPV assay in SurePath Papanicolaou specimens for cervical cancer screening

INTRODUCTION

The cobas (Roche Diagnostics, Indianapolis, IN) HPV assay was approved by the US Food and Drug Administration for human papillomavirus (HPV) testing in SurePath (Becton Dickinson, Franklin Lakes, NJ) Papanicolaou specimens for cervical cancer prevention. To validate the cobas HPV assay in SurePath specimens in our institution, we compared its accuracy and clinical efficacy to that of the Cervista (Hologic, Marlborough, MA) HPV HR assay.

METHODS

This study used 138 Papanicolaou (Pap) cytology specimens collected in SurePath preservative fluid at our institution in 2018. After Pap cytology testing, the residual specimens were split for testing with the cobas and Cervista assays. Polymerase chain reaction (PCR)-based HPV testing (GP5+/GP6+) was performed on specimens with discrepant results. Clinical follow-up data were reviewed.

RESULTS

The cobas HPV and Cervista HPV HR assays showed good concordance (89.1%), with a kappa value of 0.78 (95% CI: 0.675-0.885). Fifteen specimens showed discrepant results between the 2 assays. Of 7 cases with cobas+/Cervista- results, 5 (71%) were confirmed positive by PCR. Of 8 cases with cobas-/Cervista+ results, 4 (50%) were confirmed positive by PCR. cobas HPV and Cervista HPV HR showed the same HPV-positive rate in cases of pathologically diagnosed ASC-H, LSIL, or HSIL. The sensitivities and specificities for detecting high-risk HPV of cobas HPV (93.7%, 97.3%) and Cervista HPV HR (92.1%, 94.7%) were comparable. The cobas HPV assay had false-negative results in 4 cases (5.2%) including 1 false-negative case that failed to predict CIN3.

CONCLUSIONS

The cobas HPV assay is valid in SurePath Pap cytology specimens for cervical cancer screening but has limitations of false-negative results with clinical implications.

Performance analysis of high-throughput HPV testing on three automated workflows

Primary high-risk human papillomavirus (hrHPV) DNA testing has been introduced in several countries worldwide, including The Netherlands. The objective of this study was to compare three automated workflow procedures for hrHPV testing of which the hrHPV detection assays meet the international guidelines for HPV testing. To mimic a realistic screening situation, we aimed to process 15 000 residual PreservCyt cervical samples in a period of 3 months. During a 3 months period, four technicians were involved in processing 5000 specimens per month on three automated platforms, (1) Qiagen Digene® HC2 HPV DNA test (HC2, signal amplification); (2) Roche Cobas® HPV test (DNA amplification), and (3) Hologic Aptima® HPV test (RNA amplification). We measured and scored general aspects (time-to-results, hands-on-time (HOT)), maintenance, pre-run, run and post-run aspects, inventory (orders, storage), and number of errors on a scale from 1 to 10. As determined for one complete workflow each, maximum processing capacity and HOT were 296 samples and 2 h:55 m, 282 samples and 3 h:20 m, and 264 samples and 4 h:15 m for Aptima, Cobas, and HC2, respectively. The mean throughput time per run was 5 h:51 m for Cobas in which 94 samples could be processed. For Aptima, the mean throughput time per run was 6 h:30 m for 60 samples. Mean throughput time for HC2 is longer since results were provided on day 2. In this study, the fully automated Aptima workflow scores best with a 7.2, followed by Cobas with a score of 7.1 and HC2 with a score of 5.8. Although all HPV tests used in this comparison meet the international test guidelines, the performance (workflow) characteristics of the assays vary widely. A specific choice of a laboratory for high-throughput testing can be different based on the laboratory's demands, but also hands-on-time, time-to-results/ # samples, maintenance, pre-run, run and post-run parameters, consumables, technical support, and number of errors are important operational factors for the selection of a fully automated workflow for hrHPV testing.

HPV genotyping and p16/Ki-67 test significantly improve detection rate of high-grade cervical squamous intraepithelial lesion

INTRODUCTION

Liquid-based cytology allows to apply modern and specific analyses of hrHPV genotyping in p16/Ki-67 test. All of these together could raise accuracy ratio for high-grade squamous intraepithelial lesion above 90%. The purpose of this study was to evaluate the diagnostic accuracy of LBC, hrHPV testing, and p16/Ki-67 testing in diagnosis of high-grade cervical intraepithelial lesions.

MATERIAL AND METHODS

The study consisted of 176 women, out of which 50 presented with HSIL (CIN2) SCC (cervical intraepithelial lesion grade 2 squamous cell carcinoma). 126 women with a negative Pap test were pooled into the second group of the study. All patients were resampled for LBC, HPV genotyping, and for the p16/Ki-67 test. The research was carried out between May and December 2017, and second sampling were taken from 1 to 4 months.

RESULTS

We reported a strong correlation between positive Pap test and hrHPV (p < 0.05) that met accuracy close to 90%. We noted correlations between a positive p16/Ki-67 with a positive Pap test: p < 0.001; 66% sensitivity (95% CI: 51.2-78.8%), 87.8% specificity (95% CI: 75.2-95.4%), 76.8% accuracy (95% CI: 67.2-84.7%), and OR 13.9 (95% CI: 4.9-39.2), especially HSIL and HPV16: p < 0.001; sensitivity (95% CI) 64.0, specificity (95% CI) 98.4, accuracy (95% CI) 88.6, OR (95% CI) 109.3.

CONCLUSIONS

The results of our study indicate hrHPV genotyping as a good biomarker for the triage of patients with an abnormal cytological report. In our opinion, the hrHPV test reaches the highest level of sensitivity, specificity, and accuracy, and should be considered as crucial diagnostic test in cervical screening.

Referral population studies underestimate differences between human papillomavirus assays in primary cervical screening

OBJECTIVE

We studied how representative cytologically abnormal women ("referral populations") are with respect to uncovering differences between human papillomavirus (HPV) assays in the primary screening where most women are cytologically normal.

METHODS

A total of 4997 women were tested with SurePath® cytology, and Hybrid Capture 2 (HC2), cobas, CLART and APTIMA HPV assays. Women with positive test results were offered a follow-up. For all detected HPV infections and HPV-positive high-grade cervical intraepithelial neoplasia (≥CIN2), we studied the distributions of assay-specific signal strengths in the baseline samples as documented by the assays' automatically generated reports. We calculated the likelihood of test result discordance as the proportion of HPV-positive samples that were not confirmed by all four assays.

RESULTS

Median signal strengths for HPV infections were weaker in normal than abnormal cytology (P<.001, adjusted for women's age, multiple infections and the reason for taking the sample). For HC2, they were RLU/CO 11.0 (interquartile range, IQR: 3.3-52.8) vs 124.2 (IQR: 22.8-506.9), respectively; for cobas, Ct 33.5 (IQR: 29.6-37.5) vs 26.9 (IQR: 23.7-31.3), respectively; for APTIMA, S/CO 10.2 (IQR: 5.8-11.3) vs 11.1 (IQR: 9.4-15.5), respectively. Similar patterns were observed for HPV-positive ≥CIN2. The four HPV assays more frequently returned discordant test results in normal than in abnormal cytology. Relative frequency of discordance in detecting HPV infections was 0.39 (95% confidence interval: 0.33-0.48) for abnormal vs normal cytology.

CONCLUSIONS

These data suggest that referral population studies, by not including sufficient numbers of cytology normal women, underestimate the differences between HPV assays that would become apparent in primary screening.

Performance of Roche cobas high-risk human papillomavirus (hrHPV) testing in the two most common liquid-based Papanicolaou test platforms

INTRODUCTION

High-risk human papillomavirus (hrHPV) testing is important in cervical cancer screening and management algorithms. Roche (Pleasanton, Calif.) cobas hrHPV testing is commonly performed on both ThinPrep (TP) and SurePath (SP) samples, but performance of these platforms has not been fully investigated in the literature.

MATERIALS AND METHODS

Roche hrHPV testing was performed on 47,885 (TP = 18,295; SP = 29,590) out of 130,648 consecutive Papanicolaou tests, over 16 months; 1895 of those had interpretable biopsies.

RESULTS

The overall hrHPV detection rates were similar in TP (13.5%) and SP (13.1%). The hrHPV positive rate was higher in SP (8.5%) than TP (7.3%, P < 0.0001) in women with negative cytology; the difference in other cytologic diagnosis categories was insignificant. TP samples had significantly fewer negative cytology diagnoses (7.3% versus 8.5%, P < 0.0001), more low-grade abnormalities in cytology and biopsies, and higher colposcopy referral rate (4.8% versus 2.7%, P < 0.0001) than SP. There were no differences between TP and SP in detecting ≥HSIL by hrHPV testing, cytology or biopsy. SP samples had a significantly higher rate of HPV 16/18 but a lower rate of non-16/18 hrHPV genotypes than TP.

CONCLUSIONS

Roche cobas hrHPV testing was similar in both TP and SP platforms. The significantly lower hrHPV detection rate in cytological negative TP samples is likely related to higher cytology reporting rates for indeterminate and low-grade diagnoses in TP than SP samples. Significant differences were also observed in hrHPV genotyping results between TP and SP. Clinical risk stratification based on hrHPV testing may need to take testing platforms into consideration.

HPV Prevalence in the Dutch cervical cancer screening population (DuSC study): HPV testing using automated HC2, cobas and Aptima workflows

Background

Primary high risk (hr)HPV screening will be introduced in The Netherlands in January 2017. Our aim was to determine the hrHPV prevalence in the Dutch cervical cancer screening population (DuSC study).

Methods

A total of 12,113 residual PreservCyt cervical samples from the Dutch population based cytology screening program were rendered anonymous, randomized and tested for hrHPV using 3 HPV assays on their respective automated platforms: QIAGEN’s digene® HC2 HPV DNA Test® (HC2, signal amplification), Roche Cobas® HPV test (DNA amplification) and Hologic Aptima® HPV Test (RNA amplification). To determine the agreement between results generated using the different assays, pair wise comparison of the systems was performed by determining kappa coefficients.

Results

The selected samples were representative for the population based screening program with respect to age distribution and cytology classification.

HrHPV prevalences found were: 8.5% for HC2 (n = 959), 8.1% for cobas (n = 919) and 7.5% for Aptima (n = 849), resulting in a mean hrHPV prevalence of 8.0 ± 0.5%. Although the hrHPV prevalences of the different assays are in the range of 8%, there was a significant difference in prevalence for the HC2 vs. Aptima assay (p-value = 0.007).

A clear age dependency was found, with an hrHPV prevalence ranging from 18.7 ± 1.2% in women 29-33 years of age to 4.2 ± 0.2% in women 59–63 years of age. Furthermore, a correlation between hrHPV prevalence and severity of cytology was observed, ranging from 5.5 ± 0.4% in normal cytology to 95.2 ± 1.7% in severe dysplasia.

Indeed, kappa coefficients of 0.77, 0.71 and 0.72 (HC2 vs cobas, cobas vs Aptima and Aptima vs HC2, respectively) indicated substantial agreement between the results generated by the different systems. However, looking at the hrHPV positive samples, only 48% of the samples tested positive with all 3 assays.

Conclusions

A hrHPV prevalence of 8% was found in this unselected population based screening cohort independently of using HC2, Aptima or cobas. This prevalence is higher than the previously reported 4–5% (POBASCAM and VUSA-Screen trials). Furthermore, the complete automated hrHPV detection workflow solutions from QIAGEN, Roche, and Hologic were successfully used and will be valuable for reliably implementing high throughput hrHPV testing in cervical cancer screening.