There are several studies that relate oxidative damage as possible mechanism for 
many cancers. Many studies have also shown that anti-oxidants like selenium and 
vitamin E decrease the risk for prostate cancer. The main objective of the 
Selenium and Vitamin E Cancer Prevention Trial (SELECT) study was to look for 
the benefits of selenium and vitamin E supplementation on prostate cancer. The 
study had a large sample size, stringent experimental conditions, very long 
duration, standardized laboratories for biochemical analyses and other factors 
that contribute to high external validity. The SELECT study failed to show any 
significant risk reduction for prostate cancers ascribable to selenium and 
vitamin E supplementations. Because of these conflicting results, many 
researchers argue about the methods used, supplementations administered 
(selenium and vitamin E) and indicators used for assessing levels of 
supplementations. We reviewed many epidemiological studies, clinical trials, and 
pre-clinical studies. With corroborative evidences we justify that SELECT study 
has a sound methodology and rationale. In lieu of the contrary results of the 
select study, researchers should focus on the probable mechanisms for these 
contrary findings and continue their search for newer and effective agents for 
prevention of prostate cancer.