Postdiagnostic intake of a more proinflammatory diet is associated with a higher risk of recurrence and all-cause mortality in colorectal cancer survivors

BACKGROUND: The inflammatory potential of the diet has been associated with colorectal cancer (CRC) risk, but its association with CRC prognosis is unclear. OBJECTIVE: To investigate the inflammatory potential of the diet in relation to recurrence and all-cause mortality among persons diagnosed with stage I to III CRC. METHODS: Data of the COLON study, a prospective cohort among CRC survivors were used. Dietary intake, 6 mo after diagnosis, was assessed by using a food frequency questionnaire and was available for 1631 individuals. The empirical dietary inflammatory pattern (EDIP) score was used as a proxy for the inflammatory potential of the diet. The EDIP score was created by using reduced rank regression and stepwise linear regression to identify food groups that explained most of the variations in plasma inflammatory markers (IL6, IL8, C-reactive protein, and tumor necrosis factor-α) measured in a subgroup of survivors (n = 421). Multivariable Cox proportional hazard models with restricted cubic splines were used to investigate the relation between the EDIP score and CRC recurrence and all-cause mortality. Models were adjusted for age, sex, BMI, PAL, smoking status, stage of disease, and tumor location. RESULTS: The median follow-up time was 2.6 y (IQR: 2.1) for recurrence and 5.6 y (IQR: 3.0) for all-cause mortality, during which 154 and 239 events occurred, respectively. A nonlinear positive association between the EDIP score and recurrence and all-cause mortality was observed. For example, a more proinflammatory diet (EDIP score +0.75) compared with the median (EDIP score 0) was associated with a higher risk of CRC recurrence (HR: 1.15; 95% CI: 1.03, 1.29) and all-cause mortality (HR: 1.23; 95% CI: 1.12, 1.35). CONCLUSIONS: A more proinflammatory diet was associated with a higher risk of recurrence and all-cause mortality in CRC survivors. Further intervention studies should investigate whether a switch to a more anti-inflammatory diet improves CRC prognosis.