[Chemoprevention of breast cancer. Clinical trials in pharmacological prevention]. / Quimioprevención del cáncer de mama. Ensayos clínicos en la prevención farmacológica.

The following review article focuses on chemoprevention clinical trials of breast cancer. To date, SERMs (Selective Estrogen Receptor Modulators) have been the most studied drugs. Four randomized trials with tamoxifen vs. placebo have been performed and two with raloxifene are being carried out. Two tamoxifen trials showed between 30 and 50% reduction in breast cancer incidence. However, two other studies showed no statistical differences. Moreover, the real impact on mortality that these therapies could have is still unknown. This article includes a revision of trials that evaluated the relationship between daily vitamin intake and breast cancer. A follow up of these trials will give us answers about which patients will benefit from chemoprevention therapies.