How to Prevent Prostate Cancer: Is Screening the Best Method?

The number of prostate cancer deaths in the United States has declined in recent years, but this cancer remains one of the most common malignancies in U.S. men, with approximately 186,000 new cases and 29,000 deaths (the second leading cause of cancer death) estimated for 2008. The good news is that early detection is associated with drastically improved five-year survival rates. The bad news is that recent research questions the potential of selenium and vitamin E for preventing prostate cancer.

Screening Stats
Although the link between early screening and prostate cancer survival is well established, men are less likely to go for early screening unless they have a wife or significant other living with them, according to a study published in Cancer Epidemiology, Biomarkers and Prevention, a journal of the American Association for Cancer Research.

"In terms of motivating people to get screened, there may be benefit in targeting wives or significant others as well as men," said lead author Lauren P. Wallner, M.P.H., a graduate research associate at the University of Michigan.

Wallner and colleagues identified 2,447 Caucasian men ages 40 years to 79 years from Olmstead County, Minn. These men completed questionnaires containing queries on family history of prostate cancer, concern about getting prostate cancer and marital status.

If men had a family history of prostate cancer, they were 50 percent more likely to be screened. If men said they were worried about prostate cancer, they were nearly twice as likely to be screened. However, the likelihood among men with a family history to get screened decreased if they lived alone. Specifically, men who lived alone were 40 percent less likely to be screened than those who were married or had a significant other in their home.

Wallner said the study did not assess what caused a married man to be more likely to be screened. She also said that further studies would need to examine this effect in non-Caucasian populations.

In perhaps the largest cancer chemoprevention trial ever conducted, researchers have found that supplementation with vitamin E or selenium, alone or in combination, was not associated with a lower risk of prostate cancer or other cancers. This study, along with another cancer prevention study, will be published in the January 7 issue of JAMA, and both reports are being released early online because of public health implications.

Supplements: Do They Work?
Previous studies have indicated the potential of selenium and vitamin E for preventing prostate cancer. But a new study called SELECT, led by Scott M. Lippman, M.D., of the University of Texas M. D. Anderson Cancer Center, Houston, and Eric A. Klein, M.D., of the Cleveland Clinic Lerner College of Medicine, Cleveland, and colleagues, seems to negate this claim.

In this study, they examined the effects of selenium and vitamin E, alone or in combination, on the risk of prostate cancer and other health outcomes in relatively healthy men. The trial included 35,533 men, age 50 years or older for African-American men and age 55 years or older for other men at the start of the study, from the U.S., Canada and Puerto Rico.

The study begain in August 2001. Only recently was the 7-year follow-up conducted on the study participants. On September 15, 2008, the independent data and safety monitoring committee recommended the discontinuation of study supplements, because the alternative hypothesis -- that there was no evidence of benefit from the supplements -- was convincingly demonstrated and there was no possibility of a benefit to the planned degree with additional follow-up.

The researchers found that there were no statistically significant differences of prostate cancer diagnoses between the four groups: placebo, those taking selenium, those taking vitamin E, and those taking selenium + vitamin E.

"In conclusion, SELECT has definitively demonstrated that selenium, vitamin E, or selenium + vitamin E (at the tested doses and formulations) did not prevent prostate cancer in the generally healthy, heterogeneous population of men in SELECT." the authors write.