Early detection of CIN3 and cervical cancer during long-term follow-up using HPV/Pap smear co-testing and risk-adapted follow-up in a locally organised screening programme

Abstract

We evaluated compliance with human papillomavirus (HPV) testing and risk-adapted patient pathways and monitored changes in high-grade cervical disease during long-term follow-up. Women aged >30 years attending routine screening for cervical cancer were managed according to results from first-round screening tests (cytology and high-risk HPV; Hybrid Capture 2). Between February 2006 and January 2011, 19,795 of 19,947 women agreed to participate, of whom 4,067 proceeded to a second screening round 5 years after recruitment. Predefined endpoints were compliance, grade 3 cervical intraepithelial neoplasia or cancer (CIN3+), new HPV infection, HPV persistence and abnormal smears in round 2. A total of 765 of 19,795 women (3.9%) in round 1 and 41 of 4,067 (1.0%) in round 2 were referred for colposcopy. Compliance rates with colposcopy were 93.1 and 92.7%, respectively, while histological assessment was performed in 680 of 712 (95.5%) and 36 of 38 (94.7%), respectively. CIN3+ rates were 172 of 19,795 (0.87%; 95% confidence intervals: 0.7-1.0) in round 1 and 2 of 4,064 (0.05%; 95% confidence intervals: 0.006-0.2) in round 2; the difference was statistically significant (Fisher's exact test, p<0.001). After 5 years, the incidence of new HPV infection was 124 of 3,906 (3.2%) and HPV persistence was observed in 22 of 161 (13.7%). Locally organised HPV/cytology co-testing is feasible and acceptable to women. Risk-adapted management rapidly detected a high rate of prevalent CIN3+, while the subsequent long-term risk of new high-grade cervical disease was surprisingly low. It remains unclear if this phenomenon is explained by CIN3 mostly occurring early in life or by modifying the natural course of HPV infection with colposcopy and histological assessment.