Volume 1, Number 2 ----- Fall/Winter 1998
Recently, you may have heard about the results of two different clinical trials which involved the use of selenium and Vitamin E as possible preventive agents for cancer. Both of these NCI-sponsored studies showed intriguing results, but do not provide sufficient evidence to make broad recommendations to the American public, especially since researchers do not know all the possible dangers of these supplements. Instead, these studies raise research hypotheses (questions) to be further investigated. NCI is discussing the next phase of research that is needed to further test selenium and Vitamin E.
In both studies, researchers were surprised by their results. The first clinical trial, an 8-year long study involving 1,312 randomized participants, tested whether selenium could reduce the risk of recurrence of skin cancer. Selenium didn't show any protection against skin cancer. Instead, trial participants receiving selenium had fewer cases of lung, colorectal, and prostate cancers than participants receiving a dummy pill (placebo).
Researchers in the second trial, conducted in Finland with 29,133 male smokers, studied whether Vitamin E or beta-carotene could prevent lung cancer. After following the men for 5-8 years, researchers found that the supplements did not help prevent lung cancer.
Participants who took Vitamin E, however, had one-third fewer cases of and deaths from prostate cancer compared to the men who took placebo or beta-carotene.