The most frightening similarity between breast and prostate cancer is the fact that, each year close to 21,600 women and 20,500 men in Canada will be diagnosed with one of these diseases.

The Common Threads

Both breast and prostate cancers are influenced by the sex hormones. Testosterone can accelerate the growth of prostate cancer and a number of breast cancers are “fed” by estrogen. Both types of cancer have a genetic link. (If your mother had breast cancer, or your father had prostate cancer, your own chance of developing the disease is increased.)

Although there are many risk factors that cannot be reduced or eliminated (see following page), there are several measures you can take to help reduce your overall risk of developing breast or prostate cancer.

Modifiable Risk Factors

Modifiable risk factors are those that you can change. Unlike age, gender, ethnic background and the age at which periods start and end, these risk factors are under a person’s control. They include dietary intake and lifestyle factors such as exercise and smoking.

Dietary Factors

The Canadian Cancer Society now recommends that people eat from five to 10 servings of fruits and vegetables a day. The more colourful the fruit or vegetable, the higher the concentration of healthful elements. (White onions are an exception as they are high in the antioxidant, quercetin.)

Fruits and vegetables are believed to help prevent many cancers by galvanizing the immune system and preventing damage to the cells caused by oxidation. (When a cell’s nucleus is damaged, it can mutate into a cancer cell.) Cruciferous vegetables such as broccoli, Brussels sprouts and cabbage are particularly rich sources of a cancer-preventing agent called sulforaphane. (Broccoli has the highest concentration of this healthful compound.) Studies have indicated that sulforaphane is effective against both breast and prostate cancers.¹

Tomatoes have also been shown to help prevent breast and prostate cancers. Tomatoes contain a powerful antioxidant called lycopene. Several studies confirm lycopene’s role in helping prevent cellular changes leading to cancer development.

Although it has not been conclusively shown, many health professionals continue to believe that a high-fat diet contributes in some way towards the development of breast and prostate cancers. Since the female hormone, estrogen, is manufactured by fat cells, and many breast cancers are hormone-related, it is likely that a connection exists between excess fat and cancer risk. More research is needed to determine how excess fat consumption impacts the production of male hormones.

Lifestyle Factors

Physical activity: The risk of many cancers decreases with regular physical activity. Even moderate physical activity - briskly walking for at least two miles three times a week, for example, over the course of a lifetime - can reduce a woman's risk of developing breast cancer. A study conducted in 2004 found that older women who walk briskly 1.25 to 2.5 hours per week have almost a 20 percent decreased risk of breast cancer compared with women who do not exercise. Walking briskly for at least 10 hours a week reduced the risk even further.² Physical activity has also been shown to positively influence the risk of recurrence of breast cancer.

It appears that men can similarly reduce their risk of developing prostate cancer by leading an active life and keeping weight off. In a study of men being treated for prostate cancer, conducted by Johns Hopkins University, those who had gained more than 1.4 kilograms (3.5 pounds) a year between the ages of 25 and 40 were twice as likely to have a recurrence of this cancer as men who gained less weight.

Smoking: According to a report in the October, 2005 issue of Cancer Causes and Control, long-term smoking increases the risk of breast cancer in older postmenopausal women by up to 40 percent. Other studies have not shown a direct link between smoking and the development of breast cancer. Since there are no concrete answers, it is better to play it safe and avoid smoking and second-hand smoke, particularly since smoking is implicated in lung cancer development and increased risk of heart disease.

In a 2003 study, researchers at Fred Hutchinson Cancer Research Center in Seattle found that men who are long-term, heavy smokers face twice the risk of developing aggressive prostate cancer than men who have never smoked. This supports similar findings from investigators at Johns Hopkins and Harvard University.

Alcohol consumption: If you are a woman who enjoys the occasional glass of wine or beer (once or twice a week perhaps), there is no reason why you should stop - unless, of course, you are going to drive or are pregnant. Daily drinking, or drinking more than one alcoholic beverage at a time is not advisable however according to several studies linking even moderate alcohol consumption to breast cancer development.

When it comes to the development of prostate cancer, the alcohol link is more complex. Johns Hopkins researchers have found that, while moderate or even heavier drinking appears not to affect cancer risk, binge drinking (consuming the equivalent of eight or more cans of beer over one or two days) had a significant impact. Men who participated in binge drinking increased their risk 64 percent over non-drinkers.³ The researchers conclude that these findings warrant further investigation, but suggest that men not follow this particular pattern of alcohol consumption.

Unfortunately, there are no guarantees that observing these recommendations will prevent the development of breast or prostate cancer. However, healthy eating, regular exercise, not smoking, and prudent (or no) use of alcohol will help your body stay in fighting shape - and the healthier you are, the lower your chances of developing any health condition.

1. Brooks, J.D., Paton, V.G..  and Vidanes, G., Potent Induction of Phase 2 Enzymes in Human Prostate Cells by Sulforaphane. Cancer Epidemiology Biomarkers & Prevention Vol. 10, 949-954, September 2001.

2. McTiernan, A., et al. Recreational physical activity and the risk of breast cancer in postmenopausal women. Journal of the American Medical Association. Vol. 290 (September 10) Pgs. 1331-1336. 2003.

3. Platz, E.A., Leitzmann, M.F., Rimm, E.B., Willett, W.C., Giovannucci, E., Alcohol Intake, Drinking Patterns, and Risk of Prostate Cancer in a Large Prospective Cohort Study. American Journal of Epidemiology, 2004; 159:444-453.

Prostate Cancer Risk Factors

• Age: The chance of developing prostate cancer increases significantly after age 50. Close to two-thirds of all prostate cancers are diagnosed in men over the age of 65.
• Family history: Prostate cancer appears to run in some families more than others, suggesting an inherited factor. If your father or brother has prostate cancer, your own risk more than doubles.
• Race: Prostate cancer occurs about 60 percent more often in men of African ancestry than in Caucasians. This type of cancer occurs less often in Asian men. The reasons for these racial differences remain unclear.

Breast Cancer Risk Factors

• Age: As you grow older, so your risk of breast cancer increases. Close to 77 percent of women with breast cancer are over age 50 when it is diagnosed.
• Personal history: Women who have previously had breast cancer in one breast are three to four times as likely to develop breast cancer in the other breast than women who have never had breast cancer.
• Family history: If a blood-relative has developed breast cancer, your risk is slightly increased. The risk doubles if you have a first-degree relative (mother, sister, daughter) who has had breast cancer. (The risk is somewhat decreased if the cancer developed after menopause.)
• Start and end of menses: If your periods began before age 11 and/or you had a late menopause (after age 55), your risk is somewhat increased.
• Delayed childbirth: If you had your first child over age 30, or you have never had a child, you have a slightly higher risk of developing breast cancer.
• Smoking: Smoking may increase a woman’s risk of developing cancer of the breast.
• Diet: There is a markedly higher incidence of breast cancer in regions of the world where consumption of animal fats is highest, including North America. Women from areas where fat consumption is low (such as Japan) experience a much lower incidence of breast cancer.
• Alcohol consumption: Most health care authorities agree that consumption of alcohol likely increases the risk of breast cancer. In a 2002 study, Swedish researchers analyzed the dietary and beverage habits of over 60,000 women and determined that those who consumed alcohol had a 30 percent greater risk of developing breast cancer, compared to women who did not drink.⁴ Other studies strongly indicate that drinking alcohol after menopause greatly increases the risk of developing breast cancer.

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