Further research needed to develop evidence-based nutrition guidelines for cancer survivors

Cancer survivors die of non-cancer-related causes at much higher rates than the general public. In 2008, the U.S. economic burden of cancer totalled over $228 billion but only 41% of these costs involved direct cancer care. The majority of expenses were attributed to increased morbidity, lost productivity, and premature mortality. A commentary published in the March 2011 issue of the Journal of the American Dietetic Association examines the current evidence supporting nutrition recommendations for preventing cancer recurrence and managing chronic conditions prevalent in cancer survivors, as well as improving quality of life and decreasing health care costs. The commentary also describes knowledge gaps and suggests future nutrition research directions.

'As the number of cancer survivors continues to increase, opportunities to conduct longer-term research are expanding,' commented lead author Kim Robien, PhD, RD, Assistant Professor, Division of Epidemiology and Community Health; and Member, Cancer Outcomes and Survivorship Program, Masonic Cancer Centre, University of Minnesota, Minneapolis. 'With over 12 million American cancer survivors (about 4% of the population), it is time to concentrate on guidelines to help patients avoid the other complications that lead to death. Data support the hypothesis that nutrition interventions are not only likely to help with cancer outcomes, but can also be important in preventing and managing some of the chronic health conditions that can occur after cancer treatment, such as cardiovascular complications, weight gain, diabetes and other endocrine disorders, functional impairment, osteopenia and osteoporosis.'

The authors discuss current recommendations for cancer survivors, which emphasise achieving and maintaining a healthy weight; encouraging regular physical activity (for adults at least 30 minutes of moderate to vigourous physical activity every day); eating a diet rich in vegetables, fruits, and whole grains; and limiting red and processed meats and alcohol consumption. Further, the current recommendations are that cancer survivors try and obtain their nutrients from foods, rather than supplements since there have been several studies that have linked supplement intake with higher cancer-specific and all-cause mortality among cancer survivors.

Important knowledge gaps that call for further research are identified. Because most cancer patients have one or more comorbid conditions, management of these comorbidities by nutritional interventions may improve quality of life for these individuals. Another area of investigation is whether specific cancers require specific nutritional guidelines.

Finally, the authors recognise that any nutritional intervention must work with the individual patient. Despite efforts by the American Cancer Society and the World Cancer Research Fund/American Institute for Cancer Research to encourage cancer survivors to follow diet and lifestyle recommendations for cancer prevention, evidence suggests that few cancer survivors are doing so. Further research is needed to determine the optimal method and timing of interventions to promote healthy lifestyle behaviours among cancer survivors.