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

OBJECTIVE: 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. DESIGN: A multicentre randomised trial. SETTING: Ten different outpatient clinics localised in hospitals and seven gynaecological private practices in Norway. POPULATION: 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. METHODS: 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. MAIN OUTCOME MEASURES: Histological relapse of endometrial hyperplasia. RESULTS: 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). CONCLUSIONS: 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. TWEETABLE ABSTRACT: Relapse of endometrial hyperplasia after successful treatment is independent of therapy regime.