Efficacy of Human Papillomavirus Vaccination 4 Years After Conization for High-Grade Cervical Neoplasia

The aim of the study was to estimate human papillomavirus (HPV) vaccination efficacy in reducing recurrence risk within 4 years after conization for high-grade cervical neoplasia.

From January 2012 to June 2015, we performed a longitudinal, observational study (case-series study) on patients diagnosed with cervical intraepithelial neoplasia 2-3 neoplasia. Efficacy was estimated by a 95% CI of the relative risk, relative risk reduction, attributable risk, and number needed to treat. Parametric and nonparametric tests were used as appropriate to compare 160 vaccinated with 171 nonvaccinated patients. To estimate the hazard ratio of the vaccinated status, patients were subjected to multivariable analyses based on the Cox proportional hazard model. To compare recurrence-free survival, a Kaplan-Meier model and a log-rank test were applied.

The overall recurrence was 9.4% in the nonvaccinated and 2.5% in the vaccinated group (p = .009). Vaccination was associated with a significant decrease in the relative risk (73.5%, 95% CI = 21.8%-90.9%) with a mean number needed to treat of 14 patients per relapse prevented. Although positive conization margins were related to the highest recurrence risk, not being vaccinated independently increased this risk 3.5-fold in a 4-year follow-up (p = .025). Cumulative recurrence-free rates differed significantly between both groups (log-rank test: p = .009).

Our study corroborates the benefits of HPV vaccination, recommends a closer and longer follow-up in nonvaccinated women, and offers a 4-year prognosis for patients undergoing conization for high-grade cervical lesions.