Clinical validation of p16/Ki-67 dual-stained cytology triage of HPV-positive women: Results from the IMPACT trial.

Triage strategies are needed for primary human papillomavirus (HPV)-based cervical cancer screening to identify women requiring colposcopy/biopsy. We assessed the performance of p16/Ki-67 dual-stained (DS) immunocytochemistry to triage HPV-positive women and compared it to cytology, with or without HPV16/18 genotyping. A prospective observational screening study enrolled 35 263 women aged 25 to 65 years at 32 U.S. sites. Cervical samples had HPV and cytology testing, with colposcopy/biopsy for women with positive tests. Women without cervical intraepithelial neoplasia Grade 2 or worse (≥CIN2) at baseline (n = 3876) were retested after 1 year. In all, 4927 HPV-positive women with valid DS results were included in this analysis. DS sensitivity for ≥CIN2 and ≥CIN3 at baseline was 91.2% (95% confidence interval [CI]: 86.8%-94.2%) and 91.9% (95% CI: 86.1%-95.4%), respectively, in HPV16/18-positive women and 83.0% (95% CI: 78.4%-86.8%) and 86.0% (95% CI: 77.5%-91.6%) in women with 12 "other" genotypes. Using DS alone to triage HPV-positive women showed significantly higher sensitivity and specificity than HPV16/18 genotyping with cytology triage of 12 "other" genotypes, and substantially higher sensitivity but lower specificity than using cytology alone. The risk of ≥CIN2 was significantly lower in HPV-positive, DS-negative women (3.6%; 95% CI: 2.9%-4.4%), compared to triage-negative women using HPV16/18 genotyping with cytology for 12 "other" genotypes (7.4%; 95% CI: 6.4%-8.5%; P < .0001) or cytology alone (7.5%; 95% CI: 6.7%-8.4%; P < .0001). DS showed better risk stratification than cytology-based strategies and provided high reassurance against pre-cancers both at baseline and at 1-year follow-up, irrespective of the HPV genotype. DS allows for the safe triage of primary screening HPV-positive women.

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

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.