Guangdong Retrospective Clinical Cohort Study of Endometriosis

This is a single-center retrospective cohort study designed to evaluate the association between postoperative hormonal therapy and recurrence of ovarian endometrioma after conservative surgery.

Women who underwent surgery for ovarian endometrioma at the study center were screened for eligibility. Patients were included if they initiated one postoperative hormonal regimen within 1 month after surgery and continued the same single-agent treatment for at least 6 months. Patients who did not meet the continuous treatment requirement, received sequential hormonal therapy, or otherwise failed to meet the eligibility criteria were excluded.

Eligible participants were classified into 4 cohorts according to the postoperative hormonal regimen received: combined oral contraceptives (COC), gonadotropin-releasing hormone agonists (GnRH-a), dienogest (DNG), and dydrogesterone. The study was observational in nature, and treatment allocation was based on routine clinical practice rather than assignment by investigators.

The primary objective is to compare recurrence risk among the 4 postoperative hormonal treatment groups. Recurrence is defined as a newly detected ovarian cyst measuring at least 2 cm on ultrasound and documented on at least 2 examinations during follow-up. Follow-up focuses on recurrence within 2 years after surgery.

Clinical, demographic, and disease-related characteristics are collected from medical records and follow-up data. These variables include baseline patient characteristics, reproductive history, disease severity, and relevant surgical findings. The study aims to assess the comparative effectiveness of commonly used postoperative hormonal strategies for long-term management after conservative surgery for ovarian endometrioma.