Risk of vaginal cancer among hysterectomised women with cervical intraepithelial neoplasia: a population-based national cohort study

Objective To study the risk of vaginal cancer among hysterectomised women with and without cervical intraepithelial neoplasia (CIN). Design Population-based national cohort study. Setting and population All Swedish women, 5 million in total, aged 20 and up, 1987-2011 using national registries. Methods The study cohort was subdivided into four exposure groups: hysterectomised with no previous history of CIN3 and without prevalent CIN at hysterectomy; hysterectomised with a history of CIN3/adenocarcinoma in situ (AIS); hysterectomised with prevalent CIN at hysterectomy; non-hysterectomised. Main outcome measure Vaginal cancer. Results We identified 898 incident cases of vaginal cancer. Women with prevalent CIN at hysterectomy and those with a history of CIN3/AIS had incidence rates (IR) of vaginal cancer of 51.3 (95% CI 34.4-76.5) and 17.1 (95% CI 12.5-23.4) per 100 000, respectively. Age-adjusted IR-ratios (IRRs) compared with hysterectomised women with benign cervical history were 21.0 (95% CI 13.4-32.9) and 5.81 (95% CI 4.00-8.43), respectively. IR for non-hysterectomised women was 0.87 (95% CI 0.81-0.93) and IRR was 0.37 (95% CI 0.30-0.46). In hysterectomised women with prevalent CIN, the IR remained high after 15 years of follow up: 65.7 (95% CI 21.2-203.6). Conclusions Our findings suggest that hysterectomised women with prevalent CIN at surgery should be offered surveillance. Hysterectomised women without the studied risk factors have a more than doubled risk of contracting vaginal cancer compared with non-hysterectomised women in the general population. Still, the incidence rate does not justify screening.