The Effect of Diet on Breast Cancer Recurrence
abstract
This abstract is available on the publisher's site.
Access this abstract nowPurpose
The DIANA-5 randomized controlled trial assessed the effectiveness of a diet based on Mediterranean and macrobiotic traditions (macro-Mediterranean diet) in reducing breast cancer recurrence.
Patients and Methods
542 patients with breast cancer at high risk of recurrence because of estrogen receptor–negative cancer, or metabolic syndrome, or high plasma levels of insulin or testosterone. Women were randomly assigned to an active dietary intervention (IG) or a control group (CG). Both groups received the 2007 American Institute for Cancer Research/World Cancer Research Fund recommendations for cancer prevention. The intervention consisted of meetings with kitchen classes, community meals, and dietary recommendations. Recommended foods included whole grain cereals, legumes, soy products, vegetables, fruit, nuts, olive oil, and fish. Foods to be avoided were refined products, potatoes, sugar and desserts, red and processed meat, dairy products, and alcoholic drinks. A compliance Dietary Index was defined by the difference between recommended and discouraged foods.Results
Over the 5 years of follow-up, 95 patients of the IG and 98 of the CG developed breast cancer recurrence [HR = 0.99; 95% confidence interval (CI): 0.69–1.40]. The analysis by compliance to the dietary recommendations (IG and CG together) showed that the women in the upper tertile of Dietary Index change had an HR of recurrence of 0.59 (95% CI: 0.36–0.92) compared with women in the lower tertile.
Conclusions
The DIANA-5 dietary intervention trial failed to show a reduction in breast cancer recurrence, although self-reported diet at year 1 in IG and CG combined showed a protective association with the higher Dietary Index change.
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Additional Info
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The effect of Diet on Breast Cancer recurrence: the DIANA-5 randomized trial
Clin. Cancer Res 2023 Oct 17;[EPub Ahead of Print], F Berrino, A Villarini, G Gargano, V Krogh, S Grioni, M Bellegotti, E Venturelli, M Raimondi, A Traina, M Zarcone, R Amodio, MP Mano, H Johansson, S Panico, M Santucci de Magistris, M Barbero, C Gavazza, A Mercandino, E Consolaro, R Galasso, L Del Riccio, MC Bassi, M Simeoni, P Premori, P Pasanisi, B Bonanni, E BrunoFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
DIANA-5 randomized trial of a macro-Mediterranean diet for breast cancer recurrence highlights the challenges in conducting large behavioral lifestyle interventions
With advancements in treatment, breast cancer survival has improved, suggesting the need for evidence-based lifestyle guidance to reduce the risk of recurrence.
The DIANA-5 trial was designed to fill a significant research gap, assessing the impact of a macro-Mediterranean diet (recommended intake of whole grain cereals, legumes, soy products, vegetables, fruits, nuts, olive oil, and fish and avoiding refined products, potatoes, sugar, desserts, red and processed meat, dairy products, and alcoholic drinks) on 1542 breast cancer survivors at high risk for recurrence (stage I–III invasive breast cancer within the previous 5 years with either ER-negative tumors or the presence of metabolic or endocrine dysfunction). The primary objective was breast cancer recurrence at 5 years. The results showed no significant difference in breast cancer recurrence rates between the intervention and control groups (HR, 0.99; 95% CI, 0.69–1.14).
The intervention group was offered active support through kitchen courses, monthly community meals, and physical activity recommendations. Both groups received the general recommendations for cancer prevention (the 2007 AICR/WCRF Decalogue), leading to some control group contamination. The researchers believed it would be unethical not to share this information with the control group. The adherence to DIANA-5 activities in both groups was 87% in year 1 and reduced to about 60% in years 3 to 5, underscoring the challenges with adherence to a behavioral intervention for prolonged periods. Additionally, the Dietary Index (an indicator of compliance with dietary recommendations) improved in both groups; however, it was significantly better in the intervention group than in the control group. These challenges, including managing behavior change in the control group, may have weakened the intervention's effect. The findings highlight the difficulties in conducting randomized behavioral dietary trials to ensure high adherence in the intervention group while maintaining baseline dietary habits in the control group for prolonged periods throughout the study duration.
However, the analysis by compliance to the dietary recommendations in both groups showed that women in the highest tertile of Dietary Index change had reduced recurrence (HR, 0.59; 95% CI, 0.36–0.92) compared with those in the lowest tertile, which is encouraging and suggests that dietary changes may be beneficial if there is compliance.
Contrary to these findings, the LEANer trial,1 which evaluated a 6-month weight loss intervention (predominantly plant-based diet and physical activity) in 173 women with stage I to III breast cancer receiving chemotherapy, showed improved pathologic complete response rates in the intervention group compared with those in the usual care group (53% vs 28%; P = .037). The intervention was delivered individually by registered dietitians and included four weekly sessions in the first month, two biweekly sessions for months 2 and 3, and monthly sessions thereafter. Some key differences when compared with DIANA-5 were the study evaluating a short-term clinical endpoint such as pathologic complete response rates, allowing for the intervention to be better controlled, as well as more intensive counseling during the intervention.
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