Integrative Medicine > Supplements

Abstract

Nutritional Interventions and Outcome in Patients With Cancer or Preinvasive Lesions: Systematic Review

Anna A. Davies, George Davey Smith, Roger Harbord, Geertruida E. Bekkering, Jonathan A. C. Sterne, Rebecca Beynon, Steven Thomas

Affiliations of authors: Department of Social Medicine (AAD, GDS, RH, GEB, JACS, RB), Division of Maxillofacial Surgery (ST), University of Bristol, Bristol, UK.
Correspondence to: Steven Thomas, MD, PhD, Division of Maxillofacial Surgery, University of Bristol, Lower Maudlin St., Bristol BS1 2LY, U.K. (e-mail: steve.thomas{at}bristol.ac.uk ).

Methods. We searched electronic databases and reference lists to locate all eligible trials and analyzed trial quality. 
Outcome measures were all-cause and cancer mortality, disease-free survival, cancer recurrence, second primary cancer, recurrence of a preinvasive lesion, or progression to cancer. 
Results of individual trials were combined by use of random-effects meta-analyses. 

Results. We identified 59 eligible trials, 25 in patients with cancer and 34 in patients with preinvasive lesions, respectively. 
Trial quality was generally low; only three trials (two of cancer and one of preinvasive lesions) had adequate methods for generating the allocation sequence, allocation concealment, and masking both outcome assessors and participants. 
The combined odds ratio (OR) for the effect of a healthy diet—given alone or with dietary supplements, weight loss, or exercise—on all-cause mortality was 0.90 (95% confidence interval [CI] = 0.46 to 1.77). 
There was no evidence of an association between the use of antioxidant (OR = 1.01, 95% CI = 0.88 to 1.15) or retinol (OR = 0.97, 95% CI = 0.83 to 1.13) supplements and all-cause mortality. 
Meta-analyses of all other outcomes did not show clear evidence of benefit or harm. 

Conclusions. The impact of most nutritional interventions cannot be reliably estimated because of the limited number of trials, many of which were of low quality. 
There is no evidence that dietary modification by cancer patients improves survival and benefits disease prognosis.

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