Recurrence after surgery for endometrioma: a systematic review and meta-analyses.

Importance: Endometriosis is an inflammatory disease, with different forms of expression and a variety of complaints. An endometrioma, an ovarian cyst with endometrium-like lining, is one of the most common expressions of abdominal endometriosis. These endometriomas can, in addition to medical treatment, be treated surgically. After surgery, hormonal therapy is still frequently used for the treatment of endometriosis in general and prevention of recurrence of endometriomas specifically. However, not all women want or can receive postoperative hormonal treatment. It is important for this group to determine the risk of anatomical recurrence of ovarian endometrioma after surgery for an endometrioma.

Objective: To determine the recurrence rate for surgically treated endometrioma without postoperative hormonal treatment.

Data sources: We performed a systematic literature review and meta-analyses, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. MEDLINE, Embase, and the Cochrane library were searched until May 2023. The literature search was limited to women with endometrioma who received surgical treatment without postoperative hormonal treatment.

Study selection and synthesis: A distinction was made in study design including randomized controlled trials (RCTs) and cohort and retrospective studies. For assessment of risk of bias, the Cochrane Handbook for Systematic Reviews of Interventions and Risk of Bias in Non-randomized Studies - of Interventions assessment tool were used.

Main outcomes: The outcome measure included in this review was endometrioma recurrence.

Results: We screened 5,367 articles, of which 97 were systematically reviewed and 55 were included in this systematic review. Twelve of these were RCTs, 11 were prospective cohort studies, and 32 were retrospective studies. Nine RCTs had a low risk of bias. For non-RCTs, only 3 studies had a low risk of bias. Data of 23 studies were pooled in meta-analyses, performed for follow-up periods of 3, 6, 12, and 24 months. These studies showed recurrence rates of 4%, 14%, 17%, and 27%, respectively.

Conclusion and relevance: In the meta-analysis, at 24 months after surgery, the endometrioma recurrence rate showed a weighted mean of up to 27%. In this study, we aimed to determine the recurrence rate of endometrioma after surgical treatment in women without postoperative hormonal treatment use. The recurrence rates were up to 27%.

Registration number: CRD42020216541.