Dietary Modifications May Not Benefit Cancer Patients

Behind the Cancer Headlines®

July 19, 2006

A new study, a meta-analysis of 59 trials, found little evidence that diet is associated with survival or prognosis. The study was published in the Journal of the National Cancer Institute.

Numerous studies have linked dietary modifications and vitamins to cancer prevention and treatment. But researchers are worried that some dietary changes may not be harmless, a concern echoed by a European Union recommendation to tighten sales of supplements.

Steven Thomas, M.D., Ph.D., of the University of Bristol in the United Kingdom, and colleagues used database searches to identify 59 trials that investigated the effects of a diverse range of nutritional interventions on patients with a previous diagnosis of cancer or precancerous lesions. Trial results were combined using meta-analysis.

The authors suggest that the trials provide little evidence that specific interventions have any effect on disease-free survival, mortality, or recurrence. They say the impact of most nutritional interventions cannot be estimated reliably because of the limited number of trials, many of which are small or of low quality.

The authors write, "The large personal expenditure on supplements and dietary modifications by patients with cancer demonstrates an urgent need to understand their effects on cancer outcomes. This vulnerable group of people need to be better informed as diet is one of the few areas of their lives where they may feel that they have some control."

SOURCE:

Journal of the National Cancer Institute, July 19, 2006