Associations of red and processed meat with survival after colorectal cancer and differences according to timing of dietary assessment

Abstract

Little is known about the prognostic impact of red and processed meat intake or about changes in consumption after a diagnosis of colorectal cancer (CRC). We investigated associations of baseline red and processed meat with survival outcomes and explored changes in intake among CRC survivors 5 y after diagnosis. A total of 3122 patients diagnosed with CRC between 2003 and 2010 were followed for a median of 4.8 y [DACHS (Darmkrebs: Chancen der Verhütung durch Screening) study]. Patients provided information on diet and other factors in standardized questionnaires at baseline and at the 5-y follow-up. Cox proportional hazards regression models were used to estimate HRs and 95% CIs. Among patients with stage I-III CRC, baseline red and processed meat intake was not associated with overall (>1 time/d compared with <1 time/d; HR: 0.85; 95% CI: 0.67, 1.09), CRC-specific (HR: 0.83; 95% CI: 0.61, 1.14), cardiovascular disease-specific (HR: 0.92; 95% CI: 0.51, 1.68), non-CRC-specific (HR: 0.88; 95% CI: 0.59, 1.30), and recurrence-free (HR: 1.03; 95% CI: 0.80, 1.33) survival; results among stage IV patients were comparable. An association with worse overall survival was found among patients with Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutated CRC (HR: 1.99; 95% CI: 1.10, 3.56) but not with microsatellite instability or CpG island methylator phenotype (CIMP) positivity. A much lower proportion of survivors reported daily consumption of red and processed meat at the 5-y follow-up than at baseline (concordance rate: 39%; κ-value: 0.10; 95% CI: 0.07, 0.13). Our findings suggest that baseline red and processed meat intake is not associated with poorer survival among patients with CRC. The potential interaction with KRAS mutation status warrants further evaluation. Major changes in consumption measured at the 5-y follow-up may have had an impact on our survival estimates.