Gonadotropin-releasing Hormone Antagonist (relugolix) for Treatment of Uterine Adenomyosis with Symptomatic Endometriosis

Objective: To determine the effects of relugolix administration for uterine adenomyosis on uterine volume and subjective symptoms. Methods: This retrospective observational study included 30 patients with clinical symptoms of endometriosis complicated with uterine adenomyosis who were treated with 40 mg/day of relugolix orally for >16 weeks. The uterine volume was calculated pre- and post-administration, and the volume percentage post-administration. Furthermore, the presence or absence of subjective post-administration symptoms and adverse effects were also examined. Results: The median (interquartile range) long diameter, short diameter, width, and volume of the patients’ uteri pre- and post-administration of relugolix significantly decreased from 9.63 (9.02–11.00) to 8.00 (6.84–9.12) cm, 6.47 (5.58–8.02) to 5.00 (4.26–5.63) cm, 6.91 (5.68–8.46) to 5.49 (4.58–6.00) cm, and 221.04 (146.52–390.26) to 111.90 (71.59–165.84) cm3, respectively ( p < 0.001 for all four items). Additionally, the uterus volume post-administration was 48.30% (33.88–62.54%) of that pre-administration. Heavy menstrual bleeding, dysmenorrhea, and chronic pelvic pain occurred in 23 (76.7%), 21 (70.0%), and 13 (43.3%) of the 30 patients, respectively; however, all patients experienced resolution of all symptoms. Nine, three, and one patients had hot flashes, mild arthralgia, and a mild headache, respectively. No cases of persistent irregular or heavy bleeding were observed during treatment. Conclusions: Relugolix contributes to volume reduction and eliminates subjective symptoms of uterine adenomyosis, suggesting that it is an effective treatment for uterine adenomyosis.