Diet Quality, Inflammation, and Quality of Life in Breast Cancer Survivors: A Cross-Sectional Analysis of Pilot Study Data.

Background: Modifiable lifestyle factors, such as diet quality, could reduce inflammation and improve quality of life (QOL) in breast cancer survivors, but data are inconclusive.

Objective: To determine whether diet quality, as measured by Healthy Eating Index-2010 (HEI-2010) score, is associated with inflammation, health status, or functional outcomes affecting QOL in survivors of early-stage breast cancer.

Design: This is a cross-sectional, secondary analysis of baseline data collected from breast cancer survivors after completion of primary therapy and before random assignment to a pilot nutritional intervention aimed at reducing side effects of aromatase inhibitor treatment.

Participants/setting: Participants were 44 postmenopausal women with stage I to III endocrine receptor-positive breast cancer receiving outpatient care at a midwestern cancer center between November 2011 and October 2013.

Main Outcome Measures: Primary outcomes were serum proinflammatory cytokines (interleukin-6 [IL-6], IL-17, and tumor necrosis factor-α receptor 2 [TNFR-2]). Secondary outcomes included QOL measured by the Stanford Health and Disability Questionnaire and the Functional Assessment of Cancer Therapy-Breast with Endocrine Subscale.

Statistical Analyses Performed: Pearson correlation coefficients (r) and linear regression models were used to evaluate the relationship of dietary variables with inflammatory cytokines and QOL measures.

Results: A higher overall HEI-2010 score (healthier diet) was associated with lower IL-6 (r=-0.46; P=0.002) and TNFR-2 (r=-0.41; P=0.006); however, associations were attenuated by body mass index (BMI) (IL=6 [r=-0.26; P=0.10]; TNFR-2 [r=-0.30; P=0.06]). In women with prior chemotherapy, a higher HEI-2010 score was strongly associated with lower IL-6 (r=-0.67; P=0.009) and TNFR-2 (r=-0.59; P=0.03) after BMI adjustment. There were no significant correlations between HEI-2010 score and QOL measures after adjustment for BMI.

Conclusions: These data suggest the need for more rigorous investigation into the relationship of diet quality, BMI, and inflammation in breast cancer survivors.