Selenium and Vitamin E Cancer Prevention Trial

Selenium and Vitamin E Cancer Prevention Trial (SELECT) was a large-scale, randomized clinical trial designed to evaluate the efficacy of selenium and vitamin E, both separately and together, in preventing prostate cancer. The trial was initiated based on earlier observational studies and smaller trials that suggested potential benefits of these supplements in reducing the risk of prostate cancer. However, SELECT aimed to provide more definitive evidence through a rigorous scientific approach.

Background

Prostate cancer is one of the most common types of cancer among men, leading to significant morbidity and mortality worldwide. The search for effective prevention strategies has been a priority in cancer research. Selenium, a trace mineral, and vitamin E, a fat-soluble antioxidant, were considered promising candidates due to their supposed anti-cancer properties.

Design and Methodology

SELECT was a phase III, double-blind, placebo-controlled trial that enrolled over 35,000 men aged 50 years and older for African Americans and 55 years and older for all other races. Participants were randomly assigned to one of four groups: selenium supplementation, vitamin E supplementation, selenium and vitamin E combined, or placebo. The primary endpoint of the study was the incidence of prostate cancer among the participants.

Results

The trial was prematurely halted in 2008, approximately five years after its inception, when interim analyses indicated that neither selenium nor vitamin E, taken alone or together, reduced the risk of prostate cancer. In fact, there were indications that vitamin E supplementation might be associated with a slight increase in the risk of prostate cancer, and selenium supplementation with a slight increase in the risk of diabetes mellitus type 2.

Conclusion

The SELECT trial concluded that selenium and vitamin E, whether taken individually or together, do not prevent prostate cancer and may even pose risks for certain health conditions. These findings had a significant impact on public health guidelines and the use of these supplements for cancer prevention.

Implications for Public Health

The results of the SELECT trial led to a reevaluation of the role of dietary supplements in cancer prevention. It underscored the importance of evidence-based recommendations for supplement use and prompted healthcare professionals to advise caution among patients considering these supplements for cancer prevention.

See Also

• Prostate Cancer
• Cancer Prevention
• Dietary Supplements
• Clinical Trial