OP31.02: Changes in endometriomas and rectovaginal endometriotic nodules during treatment with norethindrone acetate or extended‐cycle oral contraceptive

To assess the changes in the volume of endometriomas and rectovaginal endometriotic nodules (RVE) during 12-month treatment with norethindrone acetate (NETA) versus extended-cycle oral contraceptive. This patient preference prospective study included women of reproductive age with endometriosis. Patients received either continuous oral treatment with NETA (2.5 mg/day, Primolut-Nor® Schering, Milan, Italy; group A) or a 91-day extended-cycle oral contraceptive (LNG/EE 150/30 mcg for 84 days and EE 10 mcg for 7 days, Seasonique® Teva, Assago, Italy; group B) for 12 months. The volume of the lesions was assessed by virtual organ computer-aided analysis (VOCAL, GE Healthcare, USA). The changes in the volume of endometriomas and RVE were compared between baseline, after 6 and 12 months of treatment. The echogenicity of the endometriomas was subjectively evaluated by the ultrasonographer using a Likert scale. 100 patients were enrolled in the study (50 in each group). 45 patients completed the treatment in group A and 38 in group B. In both study groups, the volume of the cysts significantly decreased at 6 (p<0.05) and 12 months of treatment (p<0.05; percentage reduction: 56.5% in group A and 55.7% in group B) compared with baseline. The decrease in the volume of the cyst between 6-month and 12-month treatment reached statistical significance in both study groups (p < 0.05). After 12 months of treatment, the echogenicity of the endometriomas significantly changed in both study groups (p<0.05). After 6 and 12 months of treatment, the volume of the RVE significantly decreased in both groups compared to baseline. There was a significant reduction in the volume of the RVE between the 6 and 12 months of treatment (p<0.05 for both study groups). Both NETA and Seasonique® are effective in reducing the volume of the endometriomas and RVE.