Vaginal self-sampling for human papillomavirus (HPV) testing can increase the coverage of cervical cancer screening programs. Our primary objective was to compare the diagnostic self-sampling performance of the newly designed HerSwab™ device (Eve Medical Inc.) with a physician-collected cervical sample for the detection of cervical intraepithelial neoplasia (CIN) and cancer. We also compared the performance of HerSwab™ with the cobas® PCR Female swab.
Women (n=463) referred for colposcopy at McGill University affiliated hospitals collected two consecutive self-samples with the HerSwab™ and cobas® swabs, after receiving written and oral instructions. Randomization determined which swab was first. The colposcopist then collected a cervical sample and conducted a standard colposcopic examination with biopsies as appropriate. The HerSwab™ and physician-collected specimens were transferred to individual ThinPrep-containing vials. The cobas® swabs were suspended in cobas®PCR media. All samples were genotyped using the Roche’s cobas® 4800 HPV system. Agreement between collection methods was measured using the Kappa (k) statistic. Sensitivity and specificity and their respective 95% confidence intervals (CI) were calculated for the three HPV test results based on histological grades.
Of the 463 women, 319 (68.9%) were classified as normal, 65 (14.0%) had CIN1, 31 (6.7%) had CIN2, 46 (9.9%) had CIN3 and 2 (0.4%) women had adenocarcinoma. We found very good agreement of HPV detection between the screening methods (HerSwab™ and physician: k=0.89 for HPV16, k=0.88 for HPV16/18, k=0.81 for any high-risk HPV; HerSwab™ and cobas® swabs: k=0.92 for HPV16, k=0.89 for HPV16/18, k=0.85 for any high-risk HPV). Sensitivity and specificity of any high-risk HPV for CIN2+ by HerSwab were 83.5% (95% CI: 75.4-91.7) and 52.9% (95% CI: 47.9-57.9), respectively. Corresponding values were 83.5% (95% CI: 75.4-91.7) and 48.4% (95% CI: 43.4-53.4) for the cobas® swab, and 91.1% (95% CI: 84.9-97.4) and 52.9% (95% CI: 47.9-57.9) for physician-collected samples.
Results from CASSIS demonstrate that HerSwab™ has a good agreement with physician sampling in detecting HPV genotypes, and adequate performance in detecting high-grade lesions. Its use could overcome some of the barriers to cytology, promoting cervical cancer prevention among unscreened and under-screened women.