Women with invasive breast cancer may be able to reduce breast cancer-related mortality if they follow one of four healthy eating patterns, according to a study published in the Journal of the National Cancer Institute Cancer Spectrum.

The study included 3,660 women diagnosed with invasive breast cancer. Diet was assessed at an average of 2.3 months (range, 0.7-18.7 months) post-diagnosis. From this information, the researchers derived four dietary quality indices, including:
American Cancer Society (ACS) guidelines
Alternate Mediterranean Diet Index (aMED)
Dietary Approaches to Stop Hypertension (DASH)
2015 Healthy Eating Index (HEI)

After more than 40,888 person-years of follow-up, there were 461 breast cancer recurrences and 655 deaths.

Adjusted comparisons between extreme quintiles showed all four dietary quality indices were inversely associated with all-cause mortality, suggesting a 21% to 27% lower risk, with hazard ratios (HRs) of 0.73 for the ACS diet (95% confidence interval [CI], 0.56-0.95), 0.79 for the aMED diet (95% CI, 0.61-1.03), 0.76 for the DASH diet (95% CI, 0.58-1.00), and 0.77 for the HEI diet (95% CI, 0.60-1.01).

Similar patterns were noted for non-breast cancer mortality, with HRs of 0.69 for ACS (95% CI, 0.48-0.98), 0.73 for aMED (95% CI, 0.50-1.05), 0.55 for DASH (95% CI, 0.38-0.79), and 0.67 for HEI (95% CI, 0.48-0.94). None of the dietary quality indices were associated with recurrence or breast cancer-specific mortality.

The study only measured adherence to different diet patterns after breast cancer diagnosis and eating habits could have changed over time. The study population was also predominantly white.

Link: https://academic.oup.com/jncics/advance-article/doi/10.1093/jncics/pkab019/6156634