All men are at risk of getting prostate cancer. Women are not, because they do not have a prostate gland. Certain factors make some men more likely to develop prostate cancer than others. Some of these things can be changed, such as diet. Some factors can't be changed, such as age and genetic predisposition. In any case, knowing your risk factors and what you can do about them gives you more control over your prostate health.
Prostate cancer is the second most common cancer in men besides skin cancer. In 2009, the number of new cases of prostate cancer in the United States alone was estimated at 192,280.1 One of six men in the United States will be diagnosed during his lifetime. Some men never know they have the disease because they die of something else before prostate cancer is recognized.
There is a major controversy surrounding both screening and treatment of this disease which has been discussed in the news over the past several months. The Prostate Specific Antigen (PSA) blood test first became available for use in the 1990s and along with the digital rectal exam (DRE) has been the standard in screening for prostate cancer in its early stages before any symptoms are evident. In March of 2010, the American Cancer Society updated its screening guidelines to recommend an informed discussion between the patient and his physician before routine testing. The American Urological Society (AUA) stresses taking individual risk factors into consideration when making decisions about screening. They recommend a baseline screening at age 40 for men with a life expectancy of more than 10 years and future rescreening based on risk factors and evaluating other information such as PSA velocity (how fast it rises over time). Treatment is also controversial. There is no agreement on the best treatment. When it is diagnosed at a very early stage, prostate cancer may not require immediate treatment though it should be watched closely.2
There are usually multiple factors that contribute to the development of prostate cancer. Because a man is at risk does not mean he will get prostate cancer. On the other hand, even without risk factors other than gender, there is no guarantee that a man will not be diagnosed.
So what are the risk factors for prostate cancer?
The major risk factors for prostate cancer that have been clearly established are age, race, and family history. Some evidence exists for others based on observations such as obesity, but the research is inconclusive. More research is needed to better determine the influence of factors such as diet and supplements.
Age as a risk factor for prostate cancer
This is probably the most important risk factor for many cancers. The chance of having prostate cancer increases steeply after the age of 50. The majority of prostate cancers, approximately 65%, are diagnosed in men over 65 years old. The average age at diagnosis in the U.S. is 69. Risk by age is as follows:
> Under age 40 - 1 in 10,000
> 40 to 59 -- 1 in 38
> 60 to 69 - 1 in 153,4
Race as a risk factor for prostate cancer
The incidence of prostate cancer is as much as 60% higher among African Americans as opposed to Caucasians. The reason for this difference is not fully understood. The disease is also more aggressive in African American men and they are more than 2.5 times more likely than Caucasians to die from it. Asian men who live in Asia have the lowest risk.3,4
Family History and Genetics - Prostate cancer runs in some families. It appears to be even stronger than the established genetic link seen in colon and breast cancer. Having a father or brother with prostate cancer more than doubles your risk. The criteria for hereditary prostate cancer includes at least one of the following3,4:
> Three immediate family members were diagnosed, eg. father and two brothers
> It occurs in three generations of the family, eg. father, grandfather, son
> Two relatives have been diagnosed younger than fifty-five
Some inherited genes for prostate cancer have been identified, but they account for only a small percentage of cases. Genetic testing for these genes is not yet available and their identification appears to be more difficult than for other cancers. Men whose mothers have had breast cancer may also be at increased risk for prostate cancer, but the research so far has been inconclusive.5
Geographic location as a risk factor for prostate cancer
The highest incidence of prostate cancer is found in North America and northwestern Europe. It is less common in Asia, Africa, Central America, and South America.3,4 The incidence can change when men immigrate to other countries. For example, Japanese men typically have a low rate of prostate cancer but when they move to the United States, their incidence rises. This may be due to environment and dietary influences.
Hormones as a risk factor for prostate cancer
Androgens are male hormones that influence the growth and function of the normal prostate. They can also speed the growth of prostate cancer. It is not how much of a specific hormone that is present, but the way a man's genes respond to that hormone that makes the difference.3,4
PIN or Prostatic Intraepithelial Neoplasia as a risk factor
Almost 50% of men have PIN by the time they reach 50 years of age. PIN can be low-grade where the cells appear almost normal to high- grade, meaning the cells look more abnormal. High-grade PIN is a risk for development of prostate cancer.4
The influence of diet and supplements on prostate cancer
Lycopenes (antioxidants found in certain foods like tomatoes and watermelon), vitamin E (green leafy vegetables and whole grains) and selenium have been studied to find out if they can lower prostate cancer risk. The SELECT (Selenium and Vitamin E Cancer Prevention Trial) divided about 35,000 men into 4 groups to study the effects of Vitamin E, selenium, both supplements combined or placebo. They were followed from 7-12 years. Prostate cancer incidence did not differ among the 4 groups.6
It is believed that large amounts of red meat and high-fat dairy products may increase prostate cancer risk and may increase the risk for more aggressive prostate cancer. The Prostate Cancer Prevention Trial examined nutritional risk factors for prostate cancer among 9,559 men and found no significant effect of nutrients such as lycopene, vitamin D, vitamin E, or selenium on low or high-risk prostate cancer. However, risk of high-grade prostate cancer was linked to high intake of polyunsaturated fats (meat and dairy products). Dietary calcium was linked with low-grade prostate cancer but seemed to have a protective effect against high-grade cancer.7,8
Occupational risk factors
Farming is the one occupation that has been shown to carry an increased risk for prostate cancer. This is most likely due to the increased exposure to herbicides over many years.3
Obesity and tobacco use as risk factors
It has not been proven that being overweight or using tobacco can increase the risk of prostate cancer but when it is diagnosed in obese men or smokers, it tends to be more aggressive.4
Other factors being considered
The following factors have been studied but so far there is no convincing evidence to indicate that they would increase a man's risk of developing prostate cancer:
> Vasectomy
> Sexual activity or Abstinence
> Viruses or other prostate infections
> Bicycle riding
> Undescended testicles3,4
Some of the risk factors for prostate cancer can be controlled, such as diet and activity level. The most common recommendation is to eat a Mediterranean-type diet, eg. whole grains, legumes, green, leafy vegetables, and fish. Dairy and red meat should be avoided or minimized. Exercising 30-60 minutes 5-6 days a week is recommended, including both aerobic and resistance.5
Although genetics and family history are not in our control, it may be possible to modify these risks with lifestyle changes. A good rule of thumb is: "Anything that is heart-healthy is good for your prostate." Another recommendation is screening with a prostate-specific antigen blood test and a digital rectal exam based on your family history and age so that it can be detected at an early stage. A discussion with a health-care provider who is familiar with your health history is key to making an informed decision about screening for prostate cancer.
References
- Cancer Facts & Figures 2009: American Cancer Society.
- Gaines, KK. Editorial: Controversies in Prostate Cancer Screening and Treatment.
Urologic Nursing, 2010, May-June; 30(3): 165-166. - Bostwick, D.G., Crawford, E.D., Higano, C.S., Roach, M. (2005) American Cancer
Society's Complete Guide to Prostate Cancer. American Cancer Society, Atlanta, GA. - Walsh, P.C., Worthington, J. F. (2007) Dr. Patrick Walsh's Guide to Surviving
Prostate Cancer (ed 2). Wellness Central, New York, NY. - Espinosa, G. How Man Can Avoid Prostate Cancer. Bottom Line Health, 2010 Sep;
24(9): 7-9. - Dunn, BK; Richomnd, ES; Minasian, LM; Ryan, AM; Ford, LG. A Nutrient Approach
to Prostate Cancer Prevention: The Selenium and Vitamin E Cancer Prevention Trail
(SELECT). Nutrition & Cancer, 2010 Oct; 62(7): 896-918. - Kristal, AR; Arnold, KB; Neuhouser, ML; Goodman, P; Platz, EA; Albanes, D;
Thompson, IM. Diet, Supplement Use, and Prostate Cancer Risk: Results From the
Prostate Cancer Prevention Trial. American Journal of Epidemiology, 2010 Sep 1;
172(5): 566-77. - Thompson, IM; Ankerst, DP; Chi C; Goodman, PJ; Tangen, CM; Lucia, MS; Feng, Z;
Parnes, HL; Coltman, CA Jr. Assessing Prostate Cancer Risk: Results From the
Prostate Cancer Prevention Trial. Journal of the National Cancer Institute, 2006 Apr
19; 98(9); 529-34.
This article has been reviewed by a member of the Wellness Partners Editorial Board.
Posted March 2011
