Date of this Version
The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was one of the largest human cancer prevention trials ever undertaken. Designed to examine the role of selenium and vitamin E in preventing prostate cancer (I) as a double-blind study, SELECT administered daily 200 micrograms of selenium in the form of pure L-selenomethionine, 400 IU of synthetic D,L-α-tocopherol (vitamin E), a combination of these two components, or a placebo to four approximately equally divided groups. SELECT enrollment was undertaken between August 22, 2001 and June 24, 2004, and involved 35.533 healthy males from more than 425 participating locations in the United States, Puerto Rico, and Canada. The baseline ages of males selected were fifty years or older for African Americans, and fifty-five years or older for all others. No significant differences in prostate cancer incidence were observed in any of the groups; however, slight but statistically non-significant increases were observed in prostate cancer risk within the vitamin E group and in type 2 diabetes mellitus within the selenium group. Therefore, although SELECT was planned to include a twelve year intervention period, intervention was discontinued after a median period of 5.46 years (2).