SELECT is a research study. SELECT stands for the Selenium and Vitamin E Cancer Prevention Trial. The study is being done to see if prostate cancer can be prevented. Men who participate in this study will take two capsules a day. Some men will take only selenium or vitamin E and some will take both. Others will take a placebo (sugar capsule).

Participates receive:

• Selenium and Vitamin E, or
• Selenium and a placebo (that looks like Vitamin E), or
• Vitamin E and a placebo (that looks like selenium), or
• Two placebos

Men age 55 or older may be able to participate. African-American men may join at age 50 or older. Over 32,000 men will take part in this study. Participants will visit their local study site twice a year for at least seven years, and no more than twelve years.

SELECT is funded by the National Cancer Institute (NCI) and led by the Southwest Oncology Group, one of the largest of the NCI Clinical Trials Cooperative Groups.

Some studies suggest that taking daily selenium or vitamin E supplements may reduce the chance of getting prostate cancer. Selenium is a mineral necessary for good health. Vitamin E is also an important part of a healthy diet.

Most people get a certain amount of both from foods they eat. Many people take these supplements but no one knows for sure if they actually do help prevent cancer. The only way to get answers is to conduct a large study like this one.

Learn More About Clinical Trials (Research Studies)

Understanding Clinical Trials 

Choosing a Clinical Trial