Prostate cancer is the most frequently diagnosed cancer and the second most frequent cause of cancer death among American men. The number of reported cases of prostate cancer has increased in the past twenty years, but this may be largely due to increases in detection of the disease. Whether the actual number of prostate cancer cases changed during this time period is uncertain.
Conflicting recommendations have been made about prostate cancer screening. Some authorities recommend annual tests for men over age 50 and for high-risk men in younger age groups. Others, however, oppose routine screening because it has not been shown to save lives and because it may lead to unnecessary treatment. Men should discuss prostate cancer screening with their physicians and make individual decisions about whether to undergo this type of testing.
The only fully established risk factors for prostate cancer are increasing age, African-American ethnicity, and family history of the disease. Research has almost conclusively established a role for male hormones (androgens) in the causation of prostate cancer, but the effects of these hormones are not fully understood. No lifestyle factors (including diet and exercise) have been conclusively established as prostate cancer risk or protective factors. Among the lifestyle factors, those with the most suggestive but far from conclusive supporting evidence are above-average intakes of energy (calories), total fat, meat, and red meat. All of these risk factors have "reasonable or promising" potential to be considered risk factors, but do not yet meet the classic criteria to be considered causal factors. Other theoretical risk factors with "speculated, conflicting, or limited" support include above-average body mass index, alcohol intake (either abstinence or heavy drinking), specific types of dietary fat, and dietary intakes of poultry, fish, eggs, and milk. Potential protective factors with "speculated, conflicting, or limited" support include vitamin A, carotenoids, lycopene, vitamin D, vitamin E, and alcohol. Purported risk or protective factors with very "weak" scientific support include physical activity, number of sexual partners, history of sexually transmitted diseases, human papilloma virus (HPV) infection, vasectomy, cheese or butter intake, intake of phytoestrogens, and tobacco smoking. Purported risk factors that are not supported by the scientific evidence include vitamin E (as a risk factor), above-average body estrogen levels, and in utero exposure to diethylstilbestrol (DES).
By Kathleen Meister, M.A. Based on an original paper by: John W. Morgan, Dr.P.H., Thalia A. Beeles, M.P.H, and Katherine Y. Le, M.P.H.