As part of the former screening policy in the Netherlands, an hrHPV test is performed on cytological material in symptomatic patients, in triage after ASCUS/LSIL cytological screening results and post-CIN follow-up. Aim of the present study was to compare 3 HPV assays for the detection of hrHPV in smears from these patient groups.
A total of 1265 residual PreservCyt cervical cytological samples taken either because of symptoms or for follow-up reasons were rendered anonymous, randomized and tested for hrHPV using three automated HPV assays on their respective 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. Additionally, inter-assay agreement on hrHPV positive smears was determined for the 3 assays.
1151 samples had valid results in all of the 3 tests. The majority of patients was between 29 and 53 years old (85.8%, n=988). Of these patients 59.7% (n=688) had normal cytology, in 23.6% (n=272) ASCUS was found, 9.3% (n=108) had LSIL and 7.0% (n=81) had HSIL or invasive cancer. Analysis of the results yielded an hrHPV prevalence with Aptima of 41.1% (n=473), with HC2 of 47.9% (n=551) and with Cobas of 44.4% (n=511). Kappa coefficients of 0.81, 0.83 and 0.77 (HC2 vs Cobas, Cobas vs Aptima and Aptima vs HC2, respectively) indicate substantial agreement between the results generated. With increasing degree of cytological abnormalities the hrHPV prevalence rose from 25.8% in normal cytology to 95.7% in HSIL. The kappa values also improved. With regard to inter-assay agreement of hrHPV positive samples, 71.6% (n=426) tested positive in all 3 assays, whereas the percentage of cases that tested positive with a single method was 13.6% (n=81) and the percentage that tested positive with two methods was 14.7% (n=88). The level of hrHPV positivity in these groups is presently under investigation. Interestingly preliminary results showed that with respect to age there were 2 peaks in hrHPV prevalence (respectively at 20-29 years and in the over 60’s): Final analysis of the results will include a further division based on specific clinical indications.
As expected, an high hrHPV prevalence was found in this symptomatic patient group, with rising hrHPV positivity with increasing severity of cytology. Based on kappa-values the 3 assays showed substantial agreement.