OBJECTIVETo evaluate the prognosis of cervical intraepithelial neoplasia grade 1 (CIN1) at different follow-up time points in Chinese women and the relationship with high-risk human papillomavirus (HR-HPV) infection.

METHODSBiopsy-confirmed CIN1 women were followed up from cervical cancer screening cohorts established during 1999 to 2008 in Xiangyuan county, Yangcheng county, Qinxian county and Wuxiang county, Shanxi Province.In each follow-up visit, participants were examined by visual inspection with acetic acid, liquid-based cytology and HR-HPV DNA testing. Those with any positive results received colposcope and biopsies. The cumulative incidence rates of CIN grade 2 or worse (CIN2+) and CIN grade 3 or worse (CIN3+), regression rates and persistent rates were calculated using pathological findings as a gold standard. The risks of progression related with HR-HPV were evaluated stratified by baseline and follow-up HR-HPV status.

RESULTSA total of 228, 224, 261 and 105 CIN1 women received the 1-year, 2-year, 6-year and 11-year follow-up exams, respectively. The cumulative incidence rate of CIN2+ among baseline HR-HPV positive women was 4.8% (6/126), 10.7% (16/150), 16.9% (29/172) and 35% (19/55) in the above follow-up visits, respectively, and their risk of progression was 2.7(95%CI:0.3-22.0), 2.9 (95%CI:0.7-12.1), 12.0 (95%CI:1.7-86.2) and 30.6 (95%CI:1.9-493.5) times higher than baseline HR-HPV negative women. Moreover, the cumulative incidence of CIN2+ among women with positive HR-HPV both at baseline and follow-up visit was 11% (6/55), 14% (6/42), 17% (10/60) and 50% (13/26) in the above follow-up visits, respectively.No new CIN2+ cases were found among those with negative HR-HPV both at baseline and follow-up visits.

CONCLUSIONGiven that CIN1 progression is related to HR-HPV infection, different follow-up intervals and strategies for CIN1 should be taken according to HR-HPV infection status.