The IMproving Primary Screening And Colposcopy Triage trial: human papillomavirus, cervical cytology, and histopathologic results from the baseline and 1-year follow-up phase

Abstract

Background: An increase in human papillomavirus test volumes is expected in the near future because human papillomavirus-based screening protocols are expected to become more widely adopted.

Objective: The IMproving Primary Screening And Colposcopy Triage trial, a prospective, multicenter, US-based cervical cancer screening trial, was conducted to obtain US Food and Drug Administration approvals for the new, high-throughput cobas human papillomavirus (cobas HPV) test for use on the cobas 6800/8800 Systems (cobas HPV) for detecting cervical precancerous and cancerous cells (cervical intraepithelial neoplasia of grade 2 or worse and grade 3 or worse). Here, the baseline demographics, human papillomavirus test results, cervical cytology, and histopathologic results are presented. In addition, the baseline and 1-year risks of cervical intraepithelial neoplasia grade 2 or worse and grade 3 or worse associated with the human papillomavirus results are reported.

Study design: In total, 35,263 women aged between 25 and 65 years undergoing routine screening were enrolled; liquid-based cytology and 2 polymerase chain reaction-based tests for high-risk human papillomavirus were performed. Women with abnormal Papanicolaou cytology, women positive for high-risk human papillomavirus by either of the 2 human papillomavirus tests, and a random subset of women negative according to the Papanicolaou cytology and the 2 human papillomavirus tests were referred for a colposcopy and cervical biopsy. Women who did not meet the study endpoint were eligible for the 1-year follow-up study phase. Verification bias-adjusted cervical disease prevalence and risks and 95% confidence intervals were computed.

Results: The prevalence of atypical squamous cells of undetermined significance and worse than atypical squamous cells of undetermined significance cytology were 6.5% and 3.2%, respectively. Prevalence of high-risk human papillomavirus, human papillomavirus 16, and human papillomavirus 18 based on the new cobas HPV test were 15.1%, 3.1%, and 1.4%, respectively. Both cytologic abnormalities and human papillomavirus positivity declined with increasing age. Among women who had a colposcopy and biopsy, the prevalence of cervical intraepithelial neoplasia grade 2 or worse and grade 3 or worse were 8.8% and 3.6%, respectively. The baseline and 1-year cumulative risks for cervical intraepithelial neoplasia grade 3 or worse were 13.6% and 16.9%, respectively, among women who tested positive for human papillomavirus 16. Women who tested negative for human papillomavirus had the lowest 1-year cumulative risk for cervical intraepithelial neoplasia grade 3 or worse (0.06%).

Conclusion: The contemporary, age-specific prevalence of human papillomaviruses (including human papillomavirus 16 and 18), cytologic abnormalities, and cervical intraepithelial neoplasia in a large, US-based cervical cancer screening population provides benchmarks for healthcare policies, screening programs, and for laboratories and clinicians.

Keywords: HPV; IMPACT; IMproving Primary Screening And Colposcopy Triage; Pap cytology; cervical cancer screening; cervical intraepithelial neoplasia; real-time PCR.