Long‐term adjuvant therapy for the prevention of postoperative endometrioma recurrence: a systematic review and meta‐analysis

Ovulation seems crucial in the pathogenesis of ovarian endometriomas. Therefore, suppression of ovulation should be protective against cyst relapse after excision. The objective of this systematic review was to assess the effect of long‐term postoperative medical treatment on the risk of endometrioma recurrence. A MEDLINE search was conducted to identify all the comparative studies published in the last 12 years in the English language literature on the relation between long‐term postoperative adjuvant therapy and risk of endometrioma recurrence. Of the 12 articles assessed in detail, four were finally selected based on surgery for endometriotic cysts, postoperative medical treatment use for ≥12 months vs. expectant management, and ultrasonographic and/or histological diagnosis of endometrioma recurrence. A total of 965 women were enrolled, 726 of whom were in three cohort studies and 239 in one randomized controlled trial. Oral contraceptives (OCs) were always used as postoperative adjuvant treatment. The absolute effect of postoperative OC use was assessed by comparing “always” and “never” users. A recurrent endometrioma was identified in 33 of 423 (8%) “always” OC users and in 117 of 341 (34%) women who underwent expectant management (pooled odds ratio 0.12; 95% confidence interval 0.05–0.29). To define the effect of duration of use, “always” users were compared with “ever” users, and “ever” with “never” users, with a pooled odds ratio of, respectively, 0.21 (95% confidence interval 0.11–0.40) and 0.39 (95% confidence interval 0.23–0.66). Postoperative OC use dramatically decreased the risk of ovarian endometrioma recurrence, especially in women who used OCs regularly and for prolonged periods.