Efficacy and Safety of Long-Term Use of Dienogest in Women With Ovarian Endometrioma.

Dienogest (DNG) is a progestin with highly selective progesterone activity and minimal androgenic activity and is helpful in reducing endometriosis-related pain. This study assessed the long-term efficacy and safety and recurrence rate of endometrioma with DNG use beyond 12 months of treatment. A retrospective cohort study was conducted with data collected from 7 university-affiliated hospitals and included a total of 514 women with ovarian endometrioma. All patients received 2 mg of oral DNG daily for at least 48 weeks postoperatively. During continuation of DNG, the recurrence rate of ovarian endometrioma on ultrasound, adverse events, changes in menstrual pattern, and pain score (visual analogue scale) were analyzed. The average period of DNG administration in this study was 72.2 ± 5.2 weeks (range: 48-164). The recurrence rate of endometrioma was 1.8% (9 of 514), and the median duration to recurrence was 58 weeks (range: 24-76). Pain was described as overall improved by 82.2% of patients; 61.6% stated the pain was "improved" and 20.6% reported "much improved." The mean VAS score was 4.9 at baseline and significantly decreased to 2.68, 2.2, 1.6, and 2.6 at 12, 24, 48, and 96 weeks. Amenorrhea rate was 58.3% in the first 12 weeks and increased to 86.4% at 72 weeks. Prolonged daily administration of 2 mg DNG followed by surgery was associated with a lower recurrence rate of ovarian endometrioma and a reduced pain score and symptoms.