Norethisterone acetate in the treatment of colorectal endometriosis: a pilot study

BACKGROUND This pilot study evaluates the efficacy of norethisterone acetate in treating pain and gastrointestinal symptoms of women with colorectal endometriosis. METHODS This prospective study included 40 women with colorectal endometriosis, who had pain and gastrointestinal symptoms. Patients received norethisterone acetate (2.5 mg/day) for 12 months; in case of breakthrough bleeding, the dose of norethisterone acetate was increased by 2.5 mg/day. The degree of patient satisfaction with treatment (primary end-point) and the changes in symptoms (secondary end-point) were evaluated. Side effects of treatment were recorded. RESULTS Norethisterone acetate determined a significant improvement in the intensity of chronic pelvic pain, deep dyspareunia, dyschezia. Treatment determined the disappearance of symptoms related to the menstrual cycle (dysmenorrhea, constipation during the menstrual cycle, diarrhoea during the menstrual cycle and cyclical rectal bleeding). The severity of diarrhoea, intestinal cramping and passage of mucus significantly improved during treatment. On the contrary, the administration of norethisterone acetate did not determine a significant effect on constipation, abdominal bloating and feeling of incomplete evacuation after bowel movements. At the completion of treatment, 57% of the patients with diarrhoea or diarrhoea during the menstrual cycle continued the treatment with norethisterone acetate compared with 17% of the patients with constipation or constipation during the menstrual cycle. CONCLUSIONS In some patients with bowel endometriosis, the administration of norethisterone acetate may determine a relief of pain and gastrointestinal symptoms. This therapy has greater benefits in patients with gastrointestinal symptoms related to the menstrual cycle, diarrhoea and intestinal cramping.