Objective: To explore the effect of screening history on the risk of cervical precancer and cancer after an human papillomavirus (HPV)-positive test.
Methods: A large health maintenance organization introduced cytology and HPV cotesting into routine clinical practice in 2003. We selected women aged 30 and older who tested HPV positive, cytology negative between January 2006 and December 2008 who had any clinical follow-up documented before January 2010 (n=26,799). The 1-year and 4-year cumulative incidence rates and rate ratios for cervical intraepithelial neoplasia grade 2 or higher (CIN 2+) with 95% confidence intervals (95% CIs) were calculated as estimates of absolute risk and relative risk, respectively. Results were stratified on immediate past HPV test and Pap results.
Results: Without consideration of past screening round, the 1-year and 4-year cumulative incidence rates for CIN 2+ after an HPV-positive, Pap-negative result were 2.83 (95% CI 2.55-3.12) and 7.89 (95% CI 7.00-8.78). However, risks varied substantially by past screening result. For example, the 4-year risk of CIN2+ was greater for women who had a past HPV-positive, Pap-negative result (cumulative incidence rate=11.79, 95% CI 10.22-13.36) compared with those who had HPV-negative, Pap-negative result (cumulative incidence rate=4.56, 95% CI 3.43-5.69; cumulative incidence rate ratio=2.59, 95% CI 2.30-2.87).
Conclusion: Because cervical precancer is associated with persistent HPV infection, the risk associated with an HPV-positive test can vary significantly depending on the immediate past screening round. Optimizing screening programs will require knowledge of screening history.