Objective: To evaluate the 9-year incidence of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and cumulative adherence to perform a next test in a cohort of women aged 40+ years with no cervical screening cytology within a window of 5 years (underscreened women), after baseline cervical cytology and HPV tests.
Methods: In Catalonia, Spain, co-testing with cytology and HPV test has been recommended in the Public Health system since 2006 for underscreened women. In 2007, 1,594 women with underscreened criteria were identified and followed through medical records form Pathological Department. 9-year cumulative incidence of histologically confirmed CIN2+ and cumulative adherence to perform a next test were estimated using Kaplan-Meier statistics.
Results: Follow-up was available for 1,009 women (63.3%) resulting in 23 women with. CIN2+ (2.3%). Of them, 4 women (17%) had both tests negative at baseline (3CIN2 and 1CIN3) with cumulative incidence of CIN2+ of 0.4% (95% CI: 0.1-1.4) at 5-years and 1.3% (95% CI: 0.4-3.7) at 9-years. During the first year, the prevalence among women with both tests positive was 27.0% (95% CI: 13.0-50.6) for CIN2+. Lost to follow-up was higher among women with both tests negative compared to those with both positive tests (38.7% vs 4.2%, p-value <0.001). 40.5% of the women HPV-/cyto- had a re-screening test during the 4 years following the baseline, increasing until 53.5% during the 6 years of follow-up.
Conclusions: HPV detection shows a high longitudinal predictive value at 9-year to identify women at risk to develop CIN2+. The data validate a safe extension of the 3-year screening intervals (current screening interval) to 5-year intervals in underscreened women that had negative HPV result at baseline. It is necessary to establish mechanisms to ensure screening participation and adequate follow-up for these women.