ACSM'S Health & Fitness Journal:
DEPARTMENTS: You Asked For It: Question Authority
Nieman, David C. Dr.P.H., FACSM
David C. Nieman, Dr.P.H., FACSM, is professor and director of the Human Performance Laboratory, Appalachian State University, in Boone, North Carolina; an active researcher; and author of several textbooks on health and fitness. Send your questions to firstname.lastname@example.org.
Q: I SAW IN THE NEWS RECENTLY THAT CANCER DEATHS ARE GOING UP. WHY ARE WE NOT WINNING THE WAR AGAINST CANCER? WHAT CAN I DO TO LOWER MY RISK OF GETTING CANCER?
A: Yes, the American Cancer Society (ACS) announced recently that U.S. cancer deaths rose by more than 5,000 in 2005, the latest year for which data are available (1). The overall cancer rate (adjusted for population growth) fell slightly but not nearly as much as in the previous two years. All things considered, we have entered a plateau in our war against cancer, and further gains will require a concerted effort by both American citizens and health professionals.
The ACS officials do not know why the decline in the cancer death rate has eased. Early detection of cancer through screening greatly improves the odds of surviving a cancer diagnosis (2). However, health professionals warn that as Americans lose health insurance coverage, they may get fewer screenings.
The good news is that the cancer death rate is still declining and that since the early 1990s, it is down by more than 18% for men and 10% for women. Those reductions translate to more than half a million cancer deaths avoided, according to the ACS (1). Experts attribute the success to declines in smoking, earlier detection, and more effective treatment of tumors (2). Nonetheless, as shown in the Figure, death rates for cancer have not changed much since 1950 in comparison to the steep drop in heart disease.
Figure. Death rates ...Image Tools
There is much you can do to prevent cancer (Table). The four primary cancer sites are the lung, breast, prostate, and colon-rectum. Cigarette smoking causes 87% of all lung cancers, and other cases are related to low fruit and vegetable intake (3). So the solution for lung cancer prevention is easy: don't smoke and add colorful fruits and vegetables to every meal.
TABLE American Cance...Image Tools
Breast cancer prevention is not as clear. Risk factors for breast cancer center around the "estrogen window." Several factors extend this window or increase estrogen exposure, including having your first period before age 12, not having children or having your first birth after age 30, late age at menopause, and family history of breast cancer (1,2). Other factors elevate breast cancer risk, and these include weight gain during adulthood, leading to obesity. Alcohol also increases risk to some extent, especially in women whose intake of folate from fruits and vegetables is low. Increasing evidence supports the role of moderate-to-vigorous physical activity in lowering breast cancer risk, especially when started early in life and then maintained throughout life (4). Greatly lowering fat intake also may lower breast cancer risk. Early mammography screening starting at age 40 is an essential strategy to detect breast cancer early on when treatment is most successful.
The risk of colorectal cancer is higher for those with a family history of colorectal cancer (1,2). Risk also is increased by long-term tobacco use and excessive alcohol consumption. Studies show a lower risk of colon cancer among those who are physically active on a regular basis (5). Obesity raises the risk of colon cancer in both men and women. Diets high in vegetables and fruits have been linked with lower risk, and diets high in processed and/or red meats have been linked with a higher risk of colon cancer. In addition, it is very important to follow the ACS guidelines for regular colorectal screening because finding and removing polyps in the colon can prevent colorectal cancer.
Prostate cancer risk can be lowered by adopting a diet high in certain vegetables (including tomatoes, cruciferous vegetables, soy, beans, and other legumes) or fish (1,2,6). Several studies have found that eating large amounts of red meats or dairy products may be linked with an increased risk of prostate cancer. A high-calcium intake, primarily through supplements, also has been linked to an increased risk for more aggressive types of prostate cancer. Recent studies suggest that being overweight is linked to a worse outcome in men already diagnosed with prostate cancer. Exercise, especially vigorous exercise, may offer some benefit for prostate cancer (7).
Overall, the best advice to reduce cancer risk is to avoid tobacco use, eat five or more servings of a wide variety of vegetables and fruits each day, limit intake of red meats and dairy products, avoid obesity, and maintain an active lifestyle and healthy weight. Most Americans find this type of lifestyle distasteful, and that is why we are not winning the war against cancer. The good news is that your lifestyle goes a long way in lowering your odds of getting cancer. In fact, experts claim that at least two thirds of all cancers are preventable through smart lifestyle choices and practices.
1. Jemal, A., R. Siegel, E. Ward, et al. Cancer statistics, 2008. CA: A Cancer Journal for Clinicians
2. American Cancer Society. Cancer Facts & Figures 2008
. Atlanta: American Cancer Society, 2008.
3. Linseisen, J., S. Rohrmann, A.B. Miller, et al. Fruit and vegetable consumption and lung cancer risk: updated information from the European Prospective Investigation into Cancer and Nutrition (EPIC). International Journal of Cancer
4. Dallal, C.M., J. Sullivan-Halley, R.K. Ross, et al. Long-term recreational physical activity and risk of invasive and in situ breast cancer: the California teachers study. Archives of Internal Medicine
5. Larsson, S.C., J. Rutegård, L. Bergkvist, et al. Physical activity, obesity, and risk of colon and rectal cancer in a cohort of Swedish men. European Journal of Cancer
6. Fleshner, N., and A.R. Zlotta. Prostate cancer prevention: past, present, and future. Cancer
7. Giovannucci, E.L., Y. Liu, M.F. Leitzmann, et al. A prospective study of physical activity and incident and fatal prostate cancer. Archives of Internal Medicine