From size to shape: morphological ultrasound remodeling of large ovarian endometriomas under dienogest therapy

Research Question What is the long-term efficacy of dienogest in treating large ovarian endometriomas (≥ 5 cm), assessed by transvaginal sonography (TVS) changes in size, gray-scale, color Doppler features, #Enzian score, and symptoms over time? Design This retrospective observational study included 51 women with TVS-diagnosed ovarian endometrioma ≥ 5cm, treated with dienogest 2 mg daily. TVS was performed at 6, 12, and 24 months (24-month data available for 35 patients), using International Ovarian Tumor Analysis (IOTA) terminology and #Enzian score. Pain was assessed by a visual analogue scale, and menstrual blood loss by self-perception. Results A total of 54 endometriomas were analyzed. The estimated marginal mean maximum diameter decreased from 60.0 mm (95% CI, 55.9–64.1) at baseline to 38.9 mm (95% CI, 34.8–43.0) at 6 months (p<0.001), and the reduction was sustained at 24 months (p<0.001). The estimated marginal mean volume decreased from 70.8 mL (95% CI, 61.1–80.6) at baseline to 27.7 mL (95% CI, 17.9–37.4) at 6 months (p<0.001), with the reduction persisting at 24 months (p<0.001). Ground-glass content frequency decreased from 90.7% (49/54) to 66.7% (36/54) at 6 months (p<0.001). Wall collapse was observed in 2/54 (3.7%) at baseline and in 8/54 (14.8%) at 12 months (6 vs.12 months, p=0.028). The frequency of Colour Doppler score 1 increased from 48.1% (26/54) at baseline to 66.7% (36/54) at 6 months, with a corresponding decrease in score 2 (p<0.001). The proportion of patients with #O1 endometriomas was 40.7% (22/54) at 12 months, compared with no cases at baseline (p<0.001). Severe dysmenorrhea and heavy menstrual bleeding frequency improved by 6 months. Conclusions Dienogest is effective to reduce large ovarian endometriomas volume and downstaging the #Enzian score. Recognising therapy-related TVS changes may avoid misinterpretation as atypical lesions and guide follow-up.