Risk-Benefit Index of Tamoxifen and Raloxifene for Chemoprevention of Korean Breast Cancer

Abstract

ABSTRACT Aim: According to the NSABP-P1 and P2 studies, tamoxifen and raloxifene can protect breast cancer and hip fracture, but they can induce endometrial cancer, stroke, and pulmonary embolism. We estimated the risks and benefits of tamoxifen and raloxifene using a Korean database in order to evaluate the feasibility of using tamoxifen and raloxifene for breast cancer chemoprevention in Korean women. Methods: Data were reviewed on the incidences of breast cancer, hip fracture, endometrial cancer and stroke in the absence of tamoxifen and raloxifene treatment in Korean women. We also reviewed NSABP-P1 and P2 data on the effects of tamoxifen and raloxifene on these outcomes. A risk-benefit index was calculated according to age and specific risk of breast cancer. Sensitivity analyses were performed of assumptions regarding the effects of tamoxifen and raloxifene. Results: Compared to U.S. women, the numbers of hip fractures and endometrial cancers were lower, but the number of strokes was much higher. The net benefit of tamoxifen and raloxifene were reduced with increasing age because of a high risk of stroke in older women. Older Korean women had more risk than benefit from tamoxifen and raloxifene chemoprevention. Only women younger than age 40 had a positive risk-benefit index of tamoxifen with an average 5-year risk of breast cancer in Korea. Sensitivity analysis showed that this result was robust. Raloxifene has more favorable index in postmenopausal women with a uterus. Conclusions: Women under the age 40 had more benefit than risk from tamoxifen chemoprevention. In the postmenopausal women with a uterus, raloxifene has more favorable risk-benefit index than tamoxifen. Disclosure: All authors have declared no conflicts of interest.