Relapse risk of endometrial hyperplasia after treatment with the levonorgestrel-impregnated intrauterine system or oral progestogens.

To investigate relapse rates after the successful treatment of patients with non-atypical endometrial hyperplasia who were randomised to either a levonorgestrel-impregnated intrauterine system (LNG-IUS; Mirena(®) ) or two regimens of oral medroxyprogesterone acetate (MPA) after primary histological response. A multicentre randomised trial. Ten different outpatient clinics localised in hospitals and seven gynaecological private practices in Norway. One hundred and fifty-three women aged 30-70 years with low- or medium-risk endometrial hyperplasia met the inclusion criteria, and 153 completed the therapy. Patients were randomly assigned to one of the following three treatment arms: LNG-IUS; 10 mg of oral MPA administered for 10 days per cycle for 6 months; or 10 mg of oral MPA administered daily for 6 months. The women were followed for 24 months after ending therapy. Histological relapse of endometrial hyperplasia. Histological relapse was observed in 55/135 (41%) women who had an initial complete treatment response. The relapse rates were similar in the three therapy groups (P = 0.66). In the multivariable analyses relapse was dependent on menopausal status (P = 0.0005) and estrogen level (P = 0.0007). The risk of histological relapse of non-atypical endometrial hyperplasia is high within 24 months of ceasing therapy with either the LNG-IUS or oral MPA. Continued endometrial surveillance and prolonging progestogen therapy should be considered. Relapse of endometrial hyperplasia after successful treatment is independent of therapy regime.