O033 - LONG-TERM IMPACT OF A MEDITERRANEAN DIET ON BRCA-RELATED CANCER RISK

O033

LONG-TERM IMPACT OF A MEDITERRANEAN DIET ON BRCA-RELATED CANCER RISK

A. Oliverio^1,*, E. Bruno¹, C. Meli¹, A. Daniele², S. Tommasi³, D. A. Terribile⁴, S. Magno⁵, A. Filippone⁴, C. Rossi⁴, M. M. Rossi⁴, S. Manoukian ⁶, P. Pasanisi¹, C. Rossi⁷, M. M. Rossi⁷

¹Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milano, ²Experimental Oncology and Biobank Management Unit, ³Molecular Diagnostics and Pharmacogenetics Unit, IRCCS Istituto Tumori Giovanni Paolo II, Bari, ⁴Università Cattolica S. Cuore, ⁵ Deparment of Women and Child Health and Public Health, Fondazione Policlinico Universitario A .Gemelli IRCCS, Roma, ⁶Department of Oncology and hematology, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milano, ⁷Fondazione Policlinico Universitario A. Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome , Italy

Rationale: Women carrying BRCA1/2 mutations face a high lifetime risk of breast and/or ovarian cancer. Epidemiological evidence suggests that lifestyle factors, including diet and physical activity, may influence cancer penetrance. Our Italian multicenter randomized controlled trial previously showed that a Mediterranean diet (MedDiet) with moderate protein restriction (~11% of total caloric intake) reduces circulating Insulin-like Growth Factors I (IGF-I) and other metabolic modulators of cancer risk (1). We report follow-up data collected 5 years after the end of the study, assessing the effect of the intervention on BRCA-related cancer incidence.

Methods: In this MedDiet trial, 502 women (aged 18–70) with BRCA1/2 mutations, with or without previous cancer but no metastases, were randomized to an intervention group (IG) or control group (CG). The IG participated in six full days of structured nutritional activities over six months, including cooking classes, community meals, and dietary counselling. Adherence was assessed using a Dietary Index. A total of 409 women (212 IG; 197 CG) completed the intervention. BRCA-related cancer incidence was analyzed using Cox proportional hazards models (HR, 95% CI).

Results: After a median follow-up of 6.8 years, 28 BRCA-related events occurred in the IG versus 39 in the CG (HR = 0.58; 95% CI: 0.35–0.96; p = 0.03). Among women who completed the intervention, those in the highest tertile of Dietary Index change had a HR of 0.29 (95% CI: 0.08–0.99; p = 0.05) compared to the lowest tertile. In the CG, the corresponding HR was 0.58 (95% CI: 0.20–1.63; p = 0.30).

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Conclusion: A Mediterranean diet with moderate protein restriction was associated with a significantly reduced incidence of BRCA-related cancers. These findings support the potential role of targeted dietary interventions as strategy to lower cancer risk in BRCA1/2 mutation carriers.

References: 1. PMID:33322597 

Disclosure of Interest: None declared