Estimating the Risks and Benefits of Tamoxifen Chemoprevention for Breast Cancer in Brazil

Abstract Background According to the National Surgical Adjuvant Breast and Bowel Project (NSABP-P1), tamoxifen can prevent 49% of invasive breast cancers in patients who have a five-year risk of 1.67% or more. Because tamoxifen is associated with side effects (endometrial cancer and stroke), it is necessary to weight the risks and benefits of using tamoxifen for prevention of breast cancer. The aim of this paper is to calculate a risk-benefit index based on the Brazilian population to assess the feasibility of Tamoxifen as a chemopreventive agent. Results Results showed that with increasing age, the greater the five-year risk of breast cancer would have to be for a positive risk-benefit index. This shows that more risk exists in older women with the use of tamoxifen, precisely because of the values ​​of incidence and mortality of the assessed diseases that increase with age in the population. Conclusion This study presents a methodology to determine the benefits and risks associated with chemoprevention with tamoxifen in the Brazilian population. Keywords: Breast Neoplasms, Tamoxifen, Chemoprevention