Uptake of tamoxifen in consecutive premenopausal women under surveillance in a high-risk breast cancer clinic

Background: Randomised trials of tamoxifen versus placebo indicate that tamoxifen reduces breast cancer risk by approximately 33%, yet uptake is low. Approximately 10% of women in our clinic entered the IBIS-I prevention trial. We assess the uptake of tamoxifen in a consecutive series of premenopausal women not in a trial and explore the reasons for uptake through interviews. Methods: All eligible women between 33 and 46 years at ⩾17% lifetime risk of breast cancer and undergoing annual mammography in our service were invited to take a 5-year course of tamoxifen. Reasons for accepting ( n =15) or declining ( n =15) were explored using semi-structured interviews. Results: Of 1279 eligible women, 136 (10.6%) decided to take tamoxifen. Women >40 years (74 out of 553 (13.4%)) and those at higher non- BRCA -associated risk were more likely to accept tamoxifen (129 out of 1109 (11.6%)). Interviews highlighted four themes surrounding decision making: perceived impact of side effects, the impact of others’ experience on beliefs about tamoxifen, tamoxifen as a ‘cancer drug’, and daily reminder of cancer risk. Conclusions: Tamoxifen uptake was similar to previously ascertained uptake in a randomised controlled trial (IBIS-I). Concerns were similar in women who did or did not accept tamoxifen. Decision making appeared to be embedded in the experience of significant others.