Twelve studies were included in the review: nine observational studies (n=321, range five to 105) and three case reports (n=4).
Among women with non-atypical hyperplasia, LNG-IUS was associated with a regression rate of 96% (194 out of 202); there was one case of endometrial carcinoma, detected at 12 months. Among women with atypical hyperplasia, LNG-IUS was associated with combined (complete or partial) response rate of 89% (31 out of 35). Two of the 29 responders achieved partial response only. There was one case of endometrial carcinoma, detected at six months.
Two studies (n=21 and n=66) did not distinguish between types of atypia. In one (n=21) LNG-IUS was associated with a regression rate of 62% at five months and in the other (n=66) it was associated with a 100% complete response rate at six months.