Surgical or Medical treatment of Endometrioma (SOMA trial)

The SOMA-trial (Surgery or Medication for women with endometrioMA) was designed as a multicentre, open-label, randomized controlled trial (RCT) along with a prospective cohort. Patients who were willing to participate in the clinical trial but declined randomization were treated according to their preference and participated in the prospective cohort, which followed the same study protocol. This study was carried out in 28 university- and teaching hospitals in the Netherlands and patients were recruited from May 2019 till May 2023. The RCT stopped in June 2021 before the target sample size was reached, mostly because of a strong patient preference for one of the treatment options. Recruitment continued in the prospective cohort. Patients were eligible if they had an ovarian endometrioma with a cyst diameter ≥3 cm (measured by transvaginal ultrasound or MRI). Furthermore, they had to be premenopausal, aged ≥18 years and they had to report at least one of the endometriosis related pain symptoms: dysmenorrhea, pelvic pain or dyspareunia. Patients were excluded if there were signs of deep infiltrating endometriosis (i.e. endometriosis that extends beneath the peritoneum and may affect the uterosacral ligaments, pelvic sidewalls, rectovaginal septum, vagina, bowel, bladder or ureter2) by physical examination and transvaginal ultrasound or MRI), were not able to read, write and understand Dutch or English, and were not able or willing to provide written informed consent. Patients who were assigned or had chosen surgery, received surgical treatment by a gynaecologist according to the technical description and recommendations by the Working Group of the ESHRE, ESGE and WES. Surgical treatment could include: cystectomy, cyst drainage, laser ablation, plasma energy ablation, coagulation, (salpingo)oophorectomy. Unexpected findings during surgery, as well as the performance of adhesiolysis and/or removal of peritoneal tissue or incidental deep infiltrating endometriosis, were also systematically recorded. Treatment with medication could include analgesics and/or hormonal therapy.