Breast Cancer Risk in Premenopausal Women Who Ever Used the LNG-IUS

Women remain concerned that use of any hormonal contraceptive might raise risk for breast cancer. To determine whether this potential for excess risk extends to the levonorgestrel-releasing intrauterine system (LNG-IUS), investigators conducted a manufacturer-sponsored, population-based, case-control study in Finland and Germany. Breast cancer risk associated with use of LNG-IUS versus copper intrauterine devices (IUDs) was assessed in women younger than 50 (mean age, 44). A total of 5113 women with breast cancer were matched for year of birth and area of residence with 20,452 controls without breast cancer.

No excess risk was detected among women who ever used the LNG-IUS (adjusted odds ratio, 0.99) or who were current users (aOR, 0.85). Re…