An update of controlled physical activity trials in cancer survivors: A systematic review and meta-analysis

Introduction: Approximately 11.1 million cancer survivors are alive in the United States. Activity prescriptions for cancer survivors rely on evidence as to whether exercise during or after treatment results in improved health outcomes. This systematic review and meta-analysis evaluates the extent to which physical activity during and post treatment is appropriate and effective across the cancer control continuum. Methods: A systematic quantitative review of the English language scientific literature searched controlled trials of physical activity interventions in cancer survivors during and post treatment. Data from 82 studies were abstracted, weighted mean effect sizes (WMES) were calculated from 66 high quality studies, and a systematic level of evidence criteria was applied to evaluate 60 outcomes. Reports of adverse events were abstracted from all studies. Results: Quantitative evidence shows a large effect of physical activity interventions post treatment on upper and lower body strength (WMES = 0.99 & 0.90, p < 0.0001 & 0.024, respectively) and moderate effects on fatigue and breast cancer-specific concerns (WMES = -0.54 & 0.62, p = 0.003 & 0.003, respectively). A small to moderate positive effect of physical activity during treatment was seen for physical activity level, aerobic fitness, muscular strength, functional quality of life, anxiety, and self-esteem. With few exceptions, exercise was well tolerated during and post treatment without adverse events. Conclusions: Current evidence suggests many health benefits from physical activity during and post cancer treatments. Additional studies are needed in cancer diagnoses other than breast and with a focus on survivors in greatest need of improvements for the health outcomes of interest.