Risk of progression to vaginal cancer after successful treatment of high-grade cervical intraepithelial neoplasia: a long-term cohort study in a single institution

Background: Studies on the long-term risk of treated cervical intraepithelial neoplasia (CIN), have shown that these women have a higher risk of invasive cancer in the remaining cervix or vagina, when compared to the general population. This risk persists, for at least, ten years after initial treatment. Methods: Retrospective cohort study to evaluate the long-term risk of vaginal cancer after treatment of high-grade cervical intraepithelial neoplasia. Results: The data comprised 460 women with high-grade cervical intraepithelial neoplasia treated at our institution, from January 2012 to December 2020. Three women developed vaginal cancer. The rate of invasive cancer during this period was 181 per 100 000 woman-years. The increased risk of developing cancer was noticed during the first 5 years of follow-up, in women older than 50, and with human papillomavirus (HPV) 16 infections. Conclusions: Women previously treated for high-grade lesions, are at an increased risk of developing invasive vaginal cancer. This risk is higher in older women. Follow-up of these women should be based on risk, by a combination of co-testing and clinical evaluation.