Abstract P1-07-02: Acceptability of Breast Cancer Medical Prevention by Letrozole in Post-Menopausal Women with a BRCA1/2 Mutation in the LIBER Trial

Abstract Background: Women carrying a germline BRCA1/2 mutation have a lifetime risk of developing breast cancer of 56 to 80%. Prophylactic bilateral mastectomy provides a valid option to reduce breast cancer incidence, but considerably affects the quality of life. There is therefore an urgent need to evaluate medical preventive alternative. The major breast cancer prevention trials using tamoxifen showed an approximately 50% incidence reduction in high risk women. Adjuvant trials comparing aromatase inhibitors (AI) to tamoxifen revealed a higher preventive efficacy of AI for contra-lateral cancer with fewer thrombo-embolic side effects. Patients and Methods: The French federation of cancer centres (“FNCLCC”) has designed a randomized phase III trial to determine the efficacy of letrozole to prevent breast cancer in postmenopausal BRCA1/2 carriers. The “LIBER” study is a double-blind, letrozole versus placebo study involving 32 centers among with 20 are actives. The study opened for recruitment in march 2008. Results: Here we present data reflecting the acceptability of this preventive trial. Twenty-one centers replied to an inquiry. 690 women were eligible. Out of 485 women informed by letter, 217 (44%) came to consultation and 62 (13%) entered the study. The main concerns of women while considering to enter the trial were: the potential side effects, the probability to receive the placebo and the lack of support from other practitioners. Out of 78 enrolled women, 48 (62%) were BRCA1 mutation carriers, 30 (38%) were BRCA2 mutation carriers, 73 (93%) were oophorectomized, 38 (49%) had a previous unilateral cancer, 40 (52%) did not have cancer. 30 (38%) women were less than 50 years old, and 48 (62%) were 50 or over 50 years old. Discussion: For post-menopausal women bearing a BRCA1/2 genetic predisposition, prevention of breast cancer risk by letrozole could provide a precious alternative when bilateral mastectomy is not retained. Among women who received oral information, the acceptability of this randomized double-blind letrozole versus placebo trial is 28%. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-07-02.