On Dec. 9, 2008, in contrast with earlier research suggesting that dietary supplementation with selenium and vitamin E may lower the risk of prostate cancer, initial results from the largest-ever prostate cancer prevention study, the Selenium and Vitamin E Cancer Prevention Trial (SELECT),concluded that Selenium or vitamin E, alone or in combination, did not prevent prostate cancer in this population at the doses and formulations used.

Study supplements were discontinued at the recommendation of the Data and Safety Monitoring Committee at a planned 7-year interim analysis because the evidence convincingly demonstrated no benefit from either study agent (p < 0.0001) and no possibility of a benefit to the planned degree with additional follow-up.