Updated evidence in support of diet and exercise interventions in cancer survivors

Background. A growing body of evidence suggests that diet and exercise behaviors and body weight status influence health-related outcomes after a cancer diagnosis. This review synthesizes the recent progress in lifestyle interventions in light of current guidelines put forth by the American Cancer Society (ACS), the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and the American College of Sports Medicine (ACSM). Methods. The PubMed database was searched for terms of cancer survivor(s) or neoplasms/survivor, cross-referenced with MeSH terms of lifestyle, health behavior, physical activity, exercise, body weight, obesity, weight loss, diet, nutrition, and intervention studies and limited to randomized controlled trials (RCTs) that had retention rates exceeding 75%. Results. There has been an increase in the number and methodological rigor of the studies in this area, with 21 RCTs identified in the past three years. Results suggest that physical activity interventions are safe for cancer survivors and produce improvements in fitness, strength, physical function, and cancer-related psychosocial variables, whereas dietary interventions improve diet quality, nutrition-related biomarkers and body weight. Preliminary evidence also suggests that diet and exercise may positively influence biomarkers associated with progressive disease and overall survival (e.g., insulin levels, oxidative DNA damage, tumor proliferation rates). Discussion. The evidence base regarding health-related benefits of increased physical activity, an improved diet, and weight control continues to expand. Due to the large (and increasing) number of cancer survivors, more research is needed that tests the impact of lifestyle change on health-related outcomes in this population, especially research that focuses on high-reach, sustainable interventions that recruit diverse, representative samples to help increase the generalizability of findings to the population at large. Concurrent research also needs to address relative benefit in relation to various subpopulations as defined by phenotype, genotype, and/or exposures to treatment, and other lifestyle and environmental factors.