ABSTRACT
Chemoprevention of carcinogenesis is recognized as a plausible and essential approach to win the war on cancer (Klein 2005; Bode and Dong 2009). “Success stories” include the Food and Drug Administration (FDA)–approved antiestrogen tamoxifen for the prevention of estrogen receptorpositive breast cancer (Fisher et al. 1998, 2005) and raloxifene (marketed as Evista by Eli Lilly and Company), which is an oral selective estrogen receptor modulator (SERM) that has estrogenic actions on bone and antiestrogenic actions on the uterus and breast, for the prevention of osteoporosis and invasive breast cancer in postmenopausal women (Vogel et al. 2006). A major adverse effect of tamoxifen is uterine cancer; raloxifene was associated with fewer uterine cancers. Tamoxifen increased the risk of cataracts, but raloxifene did not. Both groups had more blood clots in veins and the lungs, but that side effect was more common with tamoxifen than raloxifene (Vogel et al. 2006). For prostate cancer, the controversial 5α-reductase II inhibitor drug nasteride that blocks the intraprostatic generation of the active androgen dihydrotestosterone has been shown to decrease cancer incidence by 24.8%, but with signicant sexual side effects and questionable survival benet
26.1 Introduction .......................................................................................................................... 477 26.2 Se Nutritional Prevention of Cancer Trial Revisited ............................................................ 479 26.3 Clinical Trials Fail to Validate Preventive Activities of SeMet or Se-Yeast ........................480
