Letrozole and desogestrel-only contraceptive pill for the treatment of stage IV endometriosis

Background: It has recently been suggested that aromatase inhibitors may effectively reduce pain symptoms related to the presence of endometriosis both in postmenopausal women and in subjects of reproductive age. Aims: This study aims to evaluate the effectiveness of a combination of letrozole and desogestrel in the treatment of pain symptoms related to the presence of endometriosis. Methods: This open-label prospective study included 12 women with endometriosis-related pain symptoms that were refractory to previous medical and surgical treatments. All women had previous laparoscopy documenting stage IV endometriosis. The treatment protocol included the daily oral administration of letrozole 2.5 mg (Femara®), desogestrel 75 μg (Cerazette®), elemental calcium 1000 mg and vitamin D 880 I.U. The scheduled treatment period was six months. Results: None of the women included in the study completed the six-month treatment because all patients developed ovarian cysts; the median length of treatment was 84 days (range, 56-112). At interruption of treatment, all women reported significant improvements in dysmenorrhoea and dyspareunia. Pain symptoms quickly recurred at three-month follow up. There were no severe adverse effects of treatment; no significant change in the mineral bone density was observed during treatment. Conclusions: The combination of letrozole and desogestrel induces a relief of pain symptoms in women with endometriosis but it causes the development of ovarian cysts. Pain symptoms quickly recur after the completion of treatment.