Post-operative cyclic oral contraceptive use after gonadotrophin-releasing hormone agonist treatment effectively prevents endometrioma recurrence

Currently, no standard post-operative medical therapy has been shown to be superior in reducing the recurrence of endometrioma. This retrospective study was performed to evaluate the efficacy of post-operative cyclic oral contraceptive (OC) use after GnRH agonist (GnRHa) treatment for the prevention of endometrioma recurrence. Methods This retrospective study included 362 reproductive-aged patients who had undergone pelviscopic surgery for endometrioma. Patients were divided into two groups: a group that received cyclic, low-dose, monophasic OCs after GnRHa treatment (n = 175) and a group that received only GnRHa treatment (n = 187). Endometrioma recurrence was evaluated by an ultrasound. Results During the follow-up period (median, 35 months; range, 12-114 months), recurrent endometriomas were detected in 67 patients (18.5). Patients receiving cyclic OCs after GnRHa treatment showed a significantly reduced recurrence risk of endometrioma, when compared with patients receiving GnRHa alone (odds ratio = 0.20; 95 confidence interval, 0.10-0.38). The cumulative proportion of recurrent endometrioma after 60 months was significantly lower in OC users than in non-users (6.1 versus 43.3; P < 0.001), and a statistically significant difference was first detected at 30 months of follow-up (5.1 versus 17.1; P = 0.018). The number of GnRHa injections (3 versus 6) did not affect the recurrence rate for up to 60 months in OC non-users or users. Conclusions Post-operative cyclic OC use after GnRHa treatment effectively reduces the recurrence of endometrioma.