Effects of Diet after Early Breast Cancer Treatment: A Systematic Review and Meta-Analysis of Clinical Trials

Randomized clinical trials (RCT) are inconclusive regarding the role of dietary interventions in anthropometric measurements and survival in breast cancer patients. Our aim was to conduct a systematic review and meta-analysis to assess the effects of diet on these outcomes in women treated for early-stage breast cancer.

Embase, MEDLINE, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched for RCT comparing dietary interventions (individualized dietary counseling, prescription of a specific diet, or others) with usual care in women that were treated for early breast cancer. Primary outcomes were overall survival (OS) and disease-free survival (DFS); secondary outcome was a change in body mass index (BMI).

We found 12 RCT eligible for analysis, 7 of which were included in the quantitative analysis. Two studies reported OS and DFS and 6 reported BMI data. The hazard ratio (HR) for OS and DFS was 0.91 (95% confidence interval [CI] 0.77-1.07, p = 0.25) and 0.92 (95% CI 0.79-1.08, p = 0.31) for the intervention and control groups, respectively. Intervention was associated with BMI reduction in subjects who received a specific diet instead of counseling or other types of intervention (-0.67; 95% CI -1.14 to -0.21).

Despite increasing survival among breast cancer patients due to better oncological treatments, there is still a lack of prospective data regarding the effects of dietary interventions in this population. We found positive association between prescription of specific diets in terms of anthropometric measures; there were no differences in OS or DFS.