The SELECT trial began in 2001 to determine if taking selenium and/or vitamin E could reduce the risk of prostate cancer. University of Iowa Hospitals and Clinics was one of 400 sites participating in the study that recruited 35,000 participants. Richard Williams, MD, head of the Department of Urology at UI Hospitals and Clinics, talks about the studies initial findings and what those results mean for the prevention of prostate cancer
Who was eligible to enroll in the SELECT trial?
Healthy men—if they were Caucasian, greater than 55 years of age, and if they were African-Americans, greater than 50 years of age. African-Americans are at a higher risk at a younger age.
What were participants asked to do as part of the trial?
They were evaluated on an annual basis—a digital rectal exam and a prostate-specific antigen drawn (a blood test). Those were examined to determine whether they had increased risk for prostate cancer. Then, in terms of the study, they were randomized into groups that took selenium, vitamin E, or placebo to determine whether these drugs were helpful or not.
How were the men followed in the trial?
They would be seen on an annual basis for a digital rectal exam every six months to be sure they were doing well and to give them new amounts of the drug. They also have a serum PSA (or prostate-specific antigen) done once a year.
What did data gathered up to September 2008 suggest with regard to selenium and/or vitamin E?
We had hoped that this trial would show us that the drugs, one or both, would decrease the risk of prostate cancer in these men.
Unfortunately, what the study has shown us is that it did not decrease the risk of prostate cancer. The purpose of the study was to determine yes or no. These men helped us a great deal because they’ve allowed us to learn the answer is no.
In terms of other issues, there was some evidence, very minor and not proven, that vitamin E could slightly raise the chance of developing prostate cancer—exactly the opposite of what we were hoping. And selenium may increase the chance of developing adult onset diabetes. We will need to do further tests to determine that, but it’s only a hint, not absolute.
What happened to the SELECT trial as the result of that conclusion?
The men were taken off the medication. They were taking multivitamins, as well, and are continuing that. We continue to follow them, so they will continue to have digital rectal exams and a serum PSA done. We’re still trying to determine if they will develop prostate cancer and whether they are they at a higher risk or not.
Does this initial result end the SELECT trial?
No, it’s going to continue for two to three years to develop the rest of the data that we’re talking about.
What are the next steps with regard to this trial?
Follow the patients. Watch the PSAs, if the patient has abnormal findings on their prostate exam, they would need a biopsy. But those are things we determine based on individual patients. |
