Norethisterone acetate versus norethisterone acetate combined with letrozole for the treatment of ovarian endometriotic cysts: a patient preference study

OBJECTIVE: To compare the efficacy of norethisterone acetate (NETA, group N) or NETA and letrozole (group L) in treating endometriotic ovarian cysts. DESIGN: This patient preference study was performed between February 2010 and November 2011 in the University hospital of Genoa, Italy. MATERIALS AND METHODS: Patients with single non-recurrent en- dometriomas were treated with NETA (2.5 mg/day) or a combination of oral letrozole (2.5 mg/day), norethisterone acetate (2.5 mg/ day), elemental calcium and vitamin D3. The volume of the endometrioma was estimated by using the virtual organ computer-aided analysis (VOCAL, GE Healthcare, Milwaukee, WI, USA). The primary aim of the study was to compare the volume of the endometriotic ovarian cysts during and after treatment and to evaluate the changes in pain symp- toms. RESULTS: After 6-month of treatment, the volume of the endometrio- mas significantly decreased compared with baseline in both study groups; it was smaller in group L than in group N (p 1⁄4 0.026). 50.0% of patients in group D and 31.3% of those in group SN were satisfied of treatment (p 1⁄4 0.037). Both treatments significantly decreased the intensity of pain symptoms that recurred after discontinu- ation of treatment in both study groups. Six months after the discontin- uation of treatment, the volumes of the endometriomas were similar to baseline in both study groups. CONCLUSION: The combination of letrozole and NETA is more effective than NETA alone in reducing the size of endometriomas at 6-month follow-up but it does not cause the disappearance of endometriomas.