Record ID: MS-N080 · Family: Nutrition and dietary patterns / survivorship · Clinical question: Does an intensive macro-Mediterranean dietary program reduce breast-cancer recurrence in higher-risk survivors?

Evidence label: Randomized evidence did not show fewer recurrences; a favorable adherence analysis combined both groups and is observational.

Evidence at a glance

• Benefit: No reduction in the randomized comparison.
• Certainty: Moderate for no benefit of the tested program over already health-oriented guidance; low for the post hoc adherence association.
• Risk: Restrictive interpretation can compromise adequacy; the intervention also included activity recommendations, so effects cannot be assigned to diet alone.
• Cancer control: Not established for preventing recurrence and not a treatment for active cancer.

What was studied

DIANA-5 randomized 1,542 women, ages 35–70, with stage I–III breast cancer and higher recurrence risk to an active macro-Mediterranean program or control. Both groups received 2007 WCRF/AICR cancer-prevention recommendations.

The active program used cooking classes, community meals and advice emphasizing whole grains, legumes, soy foods, vegetables, fruit, nuts, olive oil and fish while discouraging refined foods, sugar, red and processed meat, dairy and alcohol. It also recommended physical activity. No calorie-counted diet was prescribed.

What the results show

Over five years, recurrence developed in 95 women in the intervention group and 98 controls: HR 0.99 (95% CI 0.69–1.40). The randomized intervention therefore did not reduce recurrence.

Across both groups combined, women in the highest tertile of one-year dietary-index improvement had fewer recurrences than those in the lowest tertile: HR 0.59 (95% CI 0.36–0.92). Because this was an adherence-based observational analysis, healthier behavior, prognosis and ability to adhere may be intertwined.

Important limits

• The control group also received healthy-diet guidance, narrowing the contrast.
• Dietary separation between randomized groups was smaller than planned and adherence declined over time.
• The program included physical-activity advice and intensive social support.
• The favorable adherence analysis was not the randomized treatment comparison.
• Generalisability outside Italian food patterns and program infrastructure is uncertain.

Safety and practical context

Avoid turning a qualitative pattern into an unnecessarily restrictive rule set. During active therapy, unintended weight loss, diarrhea, taste change or swallowing difficulty may require a different short-term nutrition priority.

Questions for the care team

• Am I discussing general healthy eating or a claim about recurrence prevention?
• Could this pattern cause unintended weight loss or conflict with current symptom needs?
• Which elements are realistic without excluding nutritionally important foods?
• How will adherence and weight be monitored?

Sources checked

• DIANA-5 randomized trial, Clinical Cancer Research 2024 (PMID 37847493)
• DIANA-5 registry record (NCT05019989)

Funding and conflicts: The paper reports multi-institutional Italian support; detailed funding and author disclosures were available in the full report but were not completely re-extracted here.

Last literature search: October 20, 2026 · Record appraisal: October 20, 2026

Educational information only. This record is not a prescription and does not replace advice from the oncology team, registered dietitian or oncology pharmacist.