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 letrozole combined with NETA (group L) in treating endometriotic ovarian cysts. Study design: This patient-preference study included 20 patients in group N and 20 patients in group L. The primary aim of the study was to compare the volume of the endometriomas during and after treatment. The secondary outcome was the evaluation of the changes in pain symptoms during and after treatment. Results: After six months of treatment, the volume of the endometriomas significantly decreased compared with baseline in both study groups; it was smaller in group L than in group N (p = 0.026). The rate of satisfied patients at six months of treatment was similar between the study groups (p = 0.451). No significant difference was reported between the two study groups in the amelioration of pain symptoms and in the incidence of adverse events. Conclusions: LetrozolecombinedwithNETAismoreefficaciousthanNETAaloneinreducingthevolume of endometriotic cysts but in none of the 40 patients included in the study did the endometriomas disappear. The efficacy of aromatase inhibitors, however, should be balanced with the need to administer long-term treatment.