A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

Because the exact cause of prostate cancer is still unknown, it is also unknown how to prevent prostate cancer. The following factors can raise a man’s risk of developing prostate cancer:

Age. The risk of prostate cancer increases with age, especially after age 50. More than 80% of prostate cancers are diagnosed in men who are 65 or older.

Race/ethnicity. Black men have a higher risk of prostate cancer than white men. They are more likely to develop prostate cancer at an earlier age and to have aggressive tumors that grow quickly. The exact reasons for these differences are not known and may involve socioeconomic and other factors. Hispanic men have a lower risk of developing prostate cancer and dying from the disease than white men. Prostate cancer occurs most often in North America and northern Europe. It also appears that prostate cancer is increasing among Asian people living in urbanized environments, such as Hong Kong, Singapore, and North American and European cities, particularly among those who have a more western lifestyle.

Family history. A man who has a father or brother with prostate cancer has a higher risk of developing the disease than a man who does not. Researchers have discovered specific genes that may possibly be associated with prostate cancer, although these have not yet been shown to cause prostate cancer or to be specific to this disease. Learn more about the genetics of prostate cancer.

Diet. No study has proven that diet and nutrition can directly cause or prevent the development of prostate cancer, but many studies that look at links between certain behaviors and cancer suggest there may be a connection. There is not enough information yet to make clear recommendations about the role diet plays in prostate cancer, and dietary changes may need to be made many years earlier in a man’s life to reduce the risk of developing prostate cancer. The following dietary information may be helpful:

• A diet high in fat, especially animal fat, may increase prostate cancer risk. In fact, many doctors believe that a low-fat diet may help to reduce the risk of prostate cancer in addition to having other health benefits.
• A diet high in vegetables, fruits, and legumes (beans and peas) may decrease risk of prostate cancer. It is unclear which nutrients are directly responsible. Lycopene, found in tomatoes and other vegetables, may slow or prevent cancer growth. In any case, such a diet does not cause harm and can lower a person’s blood pressure and risk of heart disease.
• Selenium, an element that people get in very small amounts from food and water, and vitamin E have been tested to find out if either or both of these nutrients can lower the risk of prostate cancer. However, in a clinical trial (a research study involving people) of more than 35,000 men called the Selenium and Vitamin E Cancer Prevention Trial (SELECT), researchers found that selenium and vitamin E supplements (pills), taken alone or together for an average of five years, did not prevent prostate cancer and may even cause harm in some men. Because of this risk, the National Cancer Institute has stopped the SELECT study. Men should talk with their doctor before taking selenium and vitamin E supplements to prevent prostate cancer.

It’s important to remember that specific changes to diet may not stop or slow the development of prostate cancer, and it’s possible such changes would need to begin early in life to have an effect.

Hormones and chemoprevention. High levels of testosterone (a male sex hormone) may speed up or cause the development of prostate cancer. For instance, it is very uncommon for a man whose body no longer makes testosterone to develop prostate cancer. And, stopping the body’s production of testosterone, called androgen deprivation therapy, often shrinks advanced prostate cancer.

A class of drugs called 5-alpha-reductase inhibitors (5-ARIs) that includes finasteride (Proscar) and dutasteride (Avodart) may lower a man’s risk of prostate cancer. In clinical trials, both drugs lowered the risk of prostate cancer. Research has suggested that some men who received these drugs have a higher risk of developing a more aggressive type of prostate cancer than the men who did not receive the drugs, possibly because they caused the prostate gland to shrink, allowing the doctors to find these more aggressive cancers. However, the data is still being reviewed, the subject is very controversial, and these drugs have not been approved yet for prostate cancer prevention by the U.S. Food and Drug Administration (FDA).

Prostate cancer early detection

Screening for prostate cancer is done to find evidence of cancer in otherwise healthy men. Two tests are commonly used to screen for prostate cancer: the PSA blood test and digital rectal examination (DRE, a test in which the doctor inserts a gloved lubricated finger into a man’s rectum and feels the surface of the prostate for any irregularities).

There is controversy about using the PSA test to look for prostate cancer in men with no symptoms of the disease. On one hand, the PSA test is useful for detecting early prostate cancer, which helps men get the treatment they need before the cancer spreads. On the other hand, PSA screening find conditions that are not cancer and slow-growing prostate cancers that would never threaten a man’s life. Because of this, screening for prostate cancer may mean that some men have surgery and other treatments that may not ever be needed. For this reason, many men and their doctors may consider active surveillance (see Treatment) of the cancer rather than immediate treatment.

Because biopsies and treatment have significant side effects, such as impotence (inability to get and maintain an erection) and incontinence (inability to control urine flow) treating it unnecessarily may seriously affect a man’s quality of life. However, it is not easy to predict which tumors will grow and spread quickly and which will grow slowly.

According to a provisional clinical opinion on PSA screening for men with no symptoms of prostate cancer, ASCO recommends that men expected to live 10 years or less should not have PSA screening and men expected to live longer than 10 years should talk with their doctors to find out if the test is appropriate for them. Every man should discuss his situation and risk of prostate cancer and work with his doctor to make a decision. To help with this discussion, ASCO provides a Decision Aid on prostate cancer screening.