Systematic review and meta-analysis shows Mediterranean diet adherence correlates with reduced mortality in cancer patients.

BACKGROUND: Cancer remains a leading global health burden, yet survival rates are improving due to better prevention and treatment advances. In this systematic review and meta-analysis we investigate the impact of adherence to the Mediterranean diet (MD) on overall and disease-free survival in cancer patients across various cancer types. METHODS: This review was conducted in accordance with PRISMA 2020 and MOOSE guidelines. A comprehensive search of PubMed/MEDLINE, Scopus, Embase, and Cochrane Library was performed up to February 28, 2024. Study quality was assessed using the Newcastle-Ottawa Scale, and the certainty of evidence was evaluated with the NUTRIGRADE approach. Pooled effect sizes were computed using a random-effects model and expressed as risk ratios, hazard ratios (HR), or odds ratios. RESULTS: Among 8314 records initially identified, 17 studies were included; sample sizes ranged from 23 to 6457. Moderate-certainty evidence showed that higher adherence to the MD was associated with reduced overall mortality in cancer patients (risk ratio: 0.96; 95% CI: 0.94-0.98), including subgroups with head and neck (HR: 0.92; 95% CI: 0.84-1.00), ovarian (HR: 0.68; 95% CI: 0.56-0.87), prostate (HR: 0.97; 95% CI: 0.95-0.99), breast (HR: 0.97; 95% CI: 0.96-0.98), and gastric cancer (HR: 0.50; 95% CI: 0.45-0.55). Moderate-certainty evidence supported improved disease-free survival in patients with breast cancer (HR: 0.39; 95% CI: 0.15-0.72). CONCLUSIONS: Higher adherence to the MD correlates with improved survival and quality of life in various cancers. It is therefore a promising, sustainable strategy to be integrated in cancer care.