Pre-operative GnRH agonist use and surgical outcomes in rectovaginal/colorectal endometriosis: an international multicentre prospective cohort study.

Background: Rectovaginal/colorectal endometriosis is severe form of endometriosis requiring complex surgery, where pre-operative gonadotrophin releasing hormone agonists (GnRHa) are used to improve the surgical outcomes but the evidence supporting this is limited.

Objectives: To evaluate the association between pre-operative use of GnRHa and perioperative and postoperative complications in patients undergoing surgery for rectovaginal or colorectal endometriosis.

Methods: We analysed prospectively collected data from British Society for Gynaecological Endoscopy-accredited endometriosis centres between 2009 and 2021. Multivariable logistic regression analysis was performed to model the odds of each complication by pre-operative GnRHa use, controlling for patient age, body mass index, smoking status, whether a hysterectomy was performed, history of previous endometriosis surgery and surgical complexity.

Main outcome measures: The association of GnRHa use with perioperative and postoperative complications.

Results: We included 9,433 patients aged 18-55 years from 101 specialist endometriosis centres from six countries including UK, USA, Sri Lanka, Saudi Arabia, Turkey and Iran. Patients receiving pre-operative GnRHa were associated with higher rate of perioperative complications [odds ratio (OR): 1.31, 95% confidence interval (CI): 1.08-1.59, P=0.007], late complications (OR: 1.477, 95% CI: 1.15-1.9, P=0.002) and pelvic haematoma (OR: 2.251, 95% CI: 1.41-3.64, P<0.001). After controlling for confounding factors, GnRHa use remained significantly associated with colostomy (aOR: 4.05: 95% CI: 1.51-12.7, P=<0.001] pelvic haematoma (aOR: 3.08, 95% CI: 1.72-5.75, P<0.001) and abscess (aOR: 2.25, 95% CI: 1.10-4.79, P=0.029). Health related quality of life (HR-QOL) improved in the Pre-GnRHa group at 12 months and 24 months (mean difference 2.09/100, 95% CI, 0.27-3.92, P=0.025) and (mean difference 2.85/100, 95% CI 0.55-5.16, P=0.015).

Conclusions: Pre-operative use of GnRHa has been associated with a higher incidence of perioperative and late complications, including significantly increased odds of colostomy, pelvic hematoma and abcess formation. There is need of careful patient counselling and further prospective research to clarify the pre-operative use of GnRHa in rectovaginal/colorectal endometriosis.

What is new?: There is need of caution use of pre-operative GnRHa in deep rectovaginal/colorectal endometriosis surgery due to increased association of the risks of complications such as colostomy, pelvic haematoma and abcess. Despite long-term improvement in HR-QOL, there is need for careful patient selection and counselling.