Physical Activity and Cancer, Part 2

by National Cancer Institute

(Page 2 of 2)

6. How might physical activity reduce prostate cancer risk?

Physical activity probably reduces men's risk for prostate cancer by 10 percent to 30 percent. The likely association between physical activity and prostate cancer is based on a small number of studies that evaluated the role of physical activity in men who developed prostate cancer. Most of these studies indicate that inactive men have higher rates of prostate cancer compared to men who are very physically active. While it is probable that men who are physically active experience a reduction in risk for prostate cancer, the potential biological mechanisms that may explain this association are unknown.

7. How might physical activity reduce endometrial cancer risk?

Studies also suggest that women who are physically active have a 30 percent to 40 percent reduced risk of endometrial cancer, with the greatest reduction in risk among those who are most active. The possible association between physical activity and endometrial cancer is based on a limited number of studies, some of which indicate that inactive women have higher rates of endometrial cancer compared to physically active women. Changes in body mass and alterations in level and metabolism of sex hormones, such as estrogen, are the major biological mechanisms thought to explain the association between physical activity and endometrial cancer. A few studies have examined whether the effect of physical activity varies according to the weight of the woman, but the results have been inconsistent.

8. How might physical activity reduce lung cancer risk?

It is possible that individuals who are physically active have a 30 percent to 40 percent reduced risk of developing lung cancer. The possible link between physical activity and lung cancer is based on a limited number of studies that have found higher rates of lung cancer among those who are physically inactive compared to those who are active, after accounting for smoking status. The relationship between physical activity and lung cancer risk is less clear for women than it is for men.

However, the results of many of these studies are difficult to interpret because smokers who are able to engage in physical activity may have much better lung function. Investigators hypothesize that improvements in pulmonary function and ventilation in active, compared to inactive individuals, may explain the possible association between lung cancer and reduced physical activity.

9. Is NCI exploring the role of physical activity in the quality of life and prognosis of cancer patients?

NCI-funded studies are exploring the ways in which physical activity may improve the quality of life of cancer patients and survivors. One study is examining the feasibility and benefits of a home-based moderate exercise program among breast cancer survivors (home-based). Another is testing the effectiveness of a nurse-directed walking exercise program to mitigate fatigue and maintain physical functioning during treatment for prostate, breast, or colorectal cancer.

For more information on these and related studies, go to: NCI Cancer Research Portfolio

10. What are some examples of NCI studies investigating the role of physical activity in cancer risk?

A number of NCI-funded studies are answering questions about the relationship between physical activity and the risk of developing cancer. For example, one study is investigating whether women who engage in moderate and strenuous physical activity have a reduced risk of endometrial and ovarian cancer, and if strenuous physical activity reduces this risk more than moderate physical activity. Another is examining the effect of one year of moderate aerobic and strength training exercise among patients with colorectal polyps.

11. Do any of these studies focus on special populations who are at increased risk of cancer?

NCI funds a number of research projects and interventions aimed at helping vulnerable populations reduce their risk for cancer by becoming more active, changing their nutritional behavior, and/or maintaining an optimal weight. Populations included in these projects include multiethnic working poor populations, African-American women, African-American church communities, rural church communities, overweight women, overweight men, and adolescents. For example, one study involving rural churches is exploring methods of helping participants to change their nutrition, activity, and exercise patterns to meet cancer risk reduction guidelines.

NCI is supporting national and regional surveys to gain more accurate information on physical activity across all age groups and diverse populations as defined by race, ethnicity, income and other factors known to influence levels of physical activity. This information will help identify groups who may benefit from programs to increase physical activity.

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