To compare the risk of CIN3+ among women who had a normal cytology (non-exposed cohort) at study start with women who had an HPV mRNA negative ASC-US/LSIL in triage (exposed cohort).
After exclusion of women who had a previous history of CIN1+ and HSIL, we identified 1063 women who had an HPV negative triage of ASC-US/LSIL over the years 2006 through 2011, and a control cohort of 25 948 women who had a normal cytology during 2006/2007. All women, aged 25-69 at study start, were residents of the counties Troms and Finnmark, Norway, and were followed through December 31, 2014. The HPV test targeted E6/E7 mRNA from the types HPV16, 18, 31, 33 and 45 (PreTect HPV-Proofer, PreTect AS). All analysis were done in SPSS version 24.0 with Chi-square test, T-test and survival analyses.
The exposed cohort were significantly younger than the non-exposed cohort. The crude cumulative proportion of CIN3+ were 2 and 8 per 1000-w.-yrs. at 42 and 78 months of follow-up for the non-exposed cohort, and 14 and 26 (95% CI: 9-43) per 1000-w.-yrs. for ASC-US-/LSIL-women. The exposed cohort had significant more extensive follow-up than the control cohort. Over the entire study period 20 cervical cancers were diagnosed in the non-exposed cohort (incidence 15.3/100 000 w.-yrs.) compared to none in the exposed cohort.
Women who have a negative mRNA-test for HPV16, 18, 31, 33 and 45 at triage for ASC-US/LSIL have low risk for CIN3 within the first two screening intervals after triage, and may return to screening at 3-year interval