Exercise and cancer

There are an estimated 13.7 million cancer survivors in the United States. Persistent and late effects of cancer therapy have contributed to an increased risk for co-morbid illness and higher all-cause mortality. Physical exercise is a targeted rehabilitative intervention following cancer therapy and a health promotion risk reduction intervention for patients as they transition into survivorship. This chapter provides a brief overview of the research on exercise and cancer survivor outcomes with a specific focus on randomized controlled trials (RCT) on the effects of exercise on body composition and bone health. There were 17 RCT trials that were identified with body composition outcomes. There was no change in weight in 16/17 trials, 4 reported decreases in percent fat mass and 2 reported increases in lean mass. Eight exercise trials were identified with bone outcomes, two of which had pharmacologic comparison arms. These trials demonstrated preservation of bone in the intervention group compared with loss in the usual care or placebo control group. The majority of trials were with breast cancer survivors, the largest survivor group. Many are overweight or obese at diagnosis; weight gain continues to increase after therapy; and treatment is associated with bone loss. The findings of the 25 trials reviewed suggest that exercise maintains weight and bone mass in a high risk population. However, differences in design, measurement of body composition and bone mass and lack of targeted exercise to the specific outcomes warrants additional research to improve the quality of life for survivors.