Use of dienogest over 53 weeks for the treatment of endometriosis

Aim To evaluate the efficacy and adverse effects of Dienogest (DNG) over 53 weeks for the treatment of endometriosis. Methods DNG was administered to 75 patients with endometriosis over a period of 53 weeks. Medical charts were retrospectively examined on the efficacy and side effects. Reduction rates of ovarian chocolate cyst, adenomyosis and changes in serum estradiol and cancer antigen 125 concentration were measured. Adverse effects, patient evaluation of their symptoms and willingness to continue taking DNG were assessed by a questionnaire. Results The median duration of treatment was 87 weeks, with the longest follow‐up duration being 120 weeks. Ovarian chocolate cysts were initially reduced; however, upon cessation of DNG treatment, an increase in size was observed. Adenomyosis lesions were reduced to some extent after 53 weeks of DNG treatment. In terms of adverse events, more than 60% (61.3%, 46/75) of patients experienced atypical genital bleeding. However, this did not prove to be a cause of discontinuation. We ceased DNG treatment in two cases because of lower abdominal pain and shoulder discomfort. Conclusions Long term DNG treatment beyond one year for endometriosis proved to be effective and safe. Ovarian chocolate cysts were markedly reduced by short‐term use of DNG, while a longer duration was required to reduce the size of adenomyosis. The decision regarding the choice of therapy lies with the individual clinician, considering a balance of efficacy with expense and adverse effects.