Physical activity, exercise, and cancer: prevention to treatment--symposium overview.

Almost 1.3 million American men and women are expected to develop cancer during 2002, and more than 550,000 will die from the disease in the same year (5). There are approximately 9 million Americans living with cancer, according to the National Cancer Institute (7). Some of these individuals have been cured of cancer, whereas others are undergoing treatment or are still considerably ill from their disease. Although some cancers are more common in the Western world, cancer affects populations throughout the world, and as countries become more developed, they take on the cancer rates of developed countries. The rising incidence of several common cancers in the last century in the United States has paralleled large changes in American lifestyle and environment. Particular lifestyle changes that could account for increasing incidence of cancer include tobacco use; increase in sedentary behavior; increased overweight and obesity; increase in dietary intake of calories, fat, and refined sugar; and reproductive pattern changes.