What Causes Prostate Cancer?

This content has been reviewed and approved by

Daniel P. Petrylak, MD
Associate Professor of Medicine
Director, Genitourinary Oncology Program
Columbia University Medical Center

The exact causes of prostate cancer are not known. But like other types of cancer, prostate cancer develops when your body rapidly produces unnecessary cells. These out of control cells can form clumps that can become cancer.

Doctors and researchers believe there are certain factors that raise your chances of getting the disease. These are called risk factors for prostate cancer. Among those risk factors are the genes you inherit, including those determining your race. Others relate to smoking, obesity, diet, hormones, and exposure to certain chemicals.

However, not everyone with risk factors develops prostate cancer. Others, who have no risk factors, can still develop the disease. The following is a listing of the most common risk factors.

• Genetic risk factors - About 9 percent of prostate cancers are caused by a “cancer susceptibility gene,” which is passed from parents to their children. If you have a father or brother who has had prostate cancer, you are at a slightly higher risk of the disease.
  
• Nongenetic risk factors 
  • Age  - It is unusual for prostate cancer to occur in men under the age of 50. Prostate cancer is most common in men over the age of 55. The average age at diagnosis is 70. The risk of prostate cancer increases rapidly after 50. In fact by 60, as many 34 percent of men have early signs of prostate cancer, whereas 70 percent of men in their 80s have the disease. 
    
  • Race  - Prostate cancer is nearly 60 percent more common among African-American men than it is among Caucasians. Japanese and Chinese men native to their country have the lowest rates of prostate cancer. Interestingly, in Japan, the incidence of prostate cancer has increased as Western diets and lifestyles have been adopted.
    
  • Diet - Western diets are an important risk factor for developing prostate cancer. Here are some facts about diet and prostate cancer:
    • Fat - Studies suggest that men who eat a high-fat diet may have a greater chance of developing prostate cancer. 
    • Fiber - Fiber intake may reduce the growth of prostate cancer. 
    • Soy protein - Soy contains isoflavones, which may inhibit the growth of prostate cancer. The Asian diet includes a lot of soy consumption, which may be related to a lower risk of prostate cancer among Japanese and Chinese men. 
    • Vitamin E and selenium 
    • Carotenoids - Food sources, such as processed tomatoes in tomato juice and tomato paste,  contain lycopenes, which have been shown to inhibit the growth of human prostate cancer cells in tissue cultures (cells grown in the laboratory). 
    • Herbal preparations - These should be used with caution as reported side effects have included venous thrombosis, breast tenderness, and loss of libido. Many herbal preparations have not been studied in men with prostate cancer. 
    • Hormones - Some research suggests that high testosterone levels may increase the risk of prostate cancer.
    • Obesity - Obesity has been associated with some common cancers, including hormone-dependent tumors, such as prostate, breast, and ovarian cancer.