Efficacy and acceptability of long-term norethindrone acetate for the treatment of rectovaginal endometriosis.

OBJECTIVE

To study the efficacy of long-term treatment with norethindrone acetate (NETA) in patients with rectovaginal endometriosis.

STUDY

DESIGN

This retrospective cohort study included 103 women with pain symptoms caused by rectovaginal endometriosis. Patients received NETA alone (2.5mg/day up to 5mg/day) for 5 years. Primary outcome was the degree of satisfaction with treatment after 5 years of progestin therapy. Secondary outcomes were the assessment of any variation in pain symptoms and the volumetric assessment of the disease by magnetic resonance imaging (MRI).

RESULTS

Sixty-one women completed the 5-year follow-up (61/103, 59.2%) with 16 women withdrawing because of adverse effects (38.1%). Overall, 68.8% (42/61) of the women who completed the study were satisfied or very satisfied of this long term NETA treatment. This represents a 40.8% (42/103) of the patients enrolled. Intensity of chronic pelvic pain and deep dyspareunia significantly decreased during treatment (p<0.001 versus baseline at 1 and 5year). Dyschezia improved after 1-year respect to baseline (p=0.008) but remained stable between first and second year (p=0.409). At the end of 5 years treatment, a radiological partial response was observed in 33 patients (55.9%, n 33/59); a stable disease in 19 patients (32.2%, n 19/59). Seven women (7/59, 11.9%) displayed a volumetric increase of rectovaginal endometriosis under NETA treatment.

CONCLUSION

Five-year therapy with NETA is safe and well tolerated by women with rectovaginal endometriosis. Due to its low cost and good pharmacological profile, it represents a good candidate for long-term treatment in this setting.