Plant-Based Dietary Patterns and Breast Cancer Recurrence and Survival in the Pathways Study

Plant-based diets are recommended for cancer survivors, but their relationship with breast cancer outcomes has not been examined. We evaluated whether long-term concordance with plant-based diets reduced the risk of recurrence and mortality among a prospective cohort of 3646 women diagnosed with breast cancer from 2005 to 2013. Participants completed food frequency questionnaires at diagnosis and 6-, 25-, and 72-month follow-up, from which we derived plant-based diet indices, including overall (PDI), healthful (hPDI), and unhealthful (uPDI). We observed 461 recurrences and 653 deaths over a median follow-up of 9.51 years. Using multivariable-adjusted Cox proportional hazards models, we estimated hazard ratios (HR) and 95% confidence intervals for breast cancer recurrence and all-cause, breast-cancer-specific, and non-breast-cancer mortality. Increased concordance with hPDI was associated with a reduced hazard of all-cause (HR 0.93, 95% CI: 0.83-1.05) and non-breast-cancer mortality (HR 0.83, 95% CI: 0.71-0.98), whereas increased concordance with uPDI was associated with increased hazards (HR 1.07, 95% CI: 0.96-1.2 and HR 1.20, 95% CI: 1.02-1.41, respectively). No associations with recurrence or breast-cancer-specific mortality were observed. In conclusion, healthful vs. unhealthful plant-based dietary patterns had differing associations with mortality. To enhance overall survival, dietary recommendations for breast cancer patients should emphasize healthful plant foods.

Automated summary

This study found that adhering to a healthful plant-based diet was associated with a reduced risk of all-cause and non-breast-cancer mortality, while adherence to an unhealthful plant-based diet was associated with increased mortality risks. No associations were observed with recurrence or breast-cancer-specific mortality.