To evaluate the long-term impact of postoperative oral contraceptive (OC) recommendation after laparoscopic cystectomy endometrioma on the incidence of endometrioma recurrence and ovarian cancer development.

This retrospective before–after cohort study included 546 patients who underwent laparoscopic cystectomy for ovarian endometrioma at a tertiary referral hospital to evaluate the post-operative OC recommendation following laparoscopic cystectomy of endometrioma introduced after the year 2005. Recurrence-free survival according to actual OC use was evaluated using Kaplan–Meier analysis and the log-rank test.

This study included 218 patients in the pre-recommendation group and 328 patients in the post-recommendation group. Baseline clinical characteristics were comparable between the two cohorts. The proportion of women who continued OC for at least 2 years increased from 3.2% in the pre-recommendation group to 38.7% in the post-recommendation group. The endometrioma recurrence rate was significantly lower in the post-recommendation group (3.8% per year) than in the pre-recommendation group (6.8% per year, p < .001). Kaplan–Meier analysis demonstrated significantly improved recurrence-free survival among women who used postoperative OCs. The number of ovarian cancer cases during the observational period (n = 4) was insufficient to draw any conclusions. There were three cases in the pre-recommendation group and one case in the post-recommendation group. None of the patients who had used OC for > 2 years developed ovarian cancer.

Introduction of the postoperative OC recommendation after laparoscopy significantly reduced the recurrence rate of ovarian endometrioma. Although a lower incidence of ovarian cancer was observed after the introduction of the recommendation, the number of events was limited and the findings should be considered exploratory.,