Risks of all-cause mortality and breast cancer-specific mortality decreased when female patients followed a more anti-inflammatory diet after their diagnosis of postmenopausal invasive breast cancer.
Risks of all-cause mortality and breast cancer-specific mortality decreased when postmenopausal female patients with invasive breast cancer followed a more anti-inflammatory diet after their diagnosis, reports NPJ Breast Cancer.
“This is the first study to indicate that a more anti-inflammatory diet after breast cancer diagnosis is associated with both better overall survival and breast cancer-specific survival,” the authors noted. They looked into this association due to the lack of evidence on how diet can influence survival outcomes post diagnosis and because there is ample proof that diet-associated inflammation is a risk factor for cancer.
Their 1064 study female enrollees were all breast cancer survivors from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) trial, and the primary study outcomes were deaths from breast cancer and any cause, as they related to the postdiagnosis dietary inflammatory index (DII). All had completed the diet history questionnaire (DHQ), and food and supplement intake were used to calculate the energy-adjusted DII (E-DII).
Following Cox regression and competing risk models, as well as a median (interquartile range) follow-up of 14.6 (IQR, 10.5-16.8) years, 296 (27.8%) of the women had died from any cause and 100 (9.4%) from breast cancer. There were 3 tertiles of E-DII scoring, from most anti-inflammatory to most pro-inflammatory dietary intake:
Compared with T1, women whose score fell among the T3 range had a higher risk of all-cause mortality (HR for T3 vs T1, 1.34; 95% CI, 1.01-1.81; Ptrend, .049), as well as breast cancer-specific mortality (HR T3 vs T1, 1.47; 95% CI, 0.89-2.43; Ptrend, 0.13; multivariable-adjusted HR for 1-unit increment, 1.10; 95% CI, 1.00-1.22).
As a composite measure, E-DII looks at how the overall diet influences inflammation instead of a specific food or nutrient.
The 10-year overall survival rate was 8.1% higher for women in the T1 group compared with the T3 group, 87.3% vs 80.7%, with the T2 group coming in at 86.6% (log-rank test, P < .001; HR, 1.16; 95% CI, 0.87-1.55 [T2 vs T1]; HR, 1.53; 95% CI, 1.15-2.03 [T3 vs T1]). However, the 10-year breast cancer-specific survival rate was highest in the T2 group, at 94.5%, which is just 1.3% above the T1 group, at 93.2%, but 7.2% greater than the T3 group, at 88.1% (log-rank test, P < 0.001; HR, 1.76; 95% CI, 1.10-2.82 [T2 vs T1]; HR, 1.70; 95% CI, 1.17-2.47 [T3 vs T1]).
Patients consuming the most pro-inflammatory diets also had higher total energy intake and BMI, more hormone therapy, a lower education level, shorter follow-up time and time from breast cancer diagnosis to DHQ completion, and less aspirin use.
Overall, these findings demonstrate a statistically significant link between mortality and postdiagnosis E-DII score for breast cancer survivors.
“This study evaluated the association of the inflammatory potential of diet with all-causes and breast cancer-specific mortality risks in a prospective cohort study of breast cancer survivors,” the authors concluded. “Our findings support that anti-inflammatory potential of a post-diagnosis diet may be a means for reducing risk of breast cancer and all-causes death among breast cancer survivors.”
They recommend additional studies with longer follow-up times and investigations into how diet affects the various breast cancer subtypes, especially those falling into the estrogen receptor-positive and -negative categories, that will enable “precise tailoring of dietary interventions for breast cancer survivors in the future.”
Wang K, Sun J-Z, Wu Q-X, et al. Long-term anti-inflammatory diet in relation to improved breast cancer prognosis: a prospective cohort study. NPJ Breast Cancer. Published online August 13, 2020. doi:10.1038/s41523-020-00179-4