Guinter MA, et al. - Among men and women with colorectal cancer (CRC), researchers prospectively assessed associations of pre- and postdiagnosis diet quality with mortality risk. Before and after CRC diagnosis, dietary patterns reflective of high intakes of plant foods and low intakes of animal products were related to longer survival.

Methods

• In the 1992/1993 baseline Cancer Prevention Study-II Nutrition Cohort, 2,801 participants were free of cancer and subsequently diagnosed with invasive, nonmetastatic CRC during follow-up through June 2013.
• Data on pre- and postdiagnostic diets were available to 2,671 and 1,321 participants, 1,414 and 722 of whom died.
• To assess diet quality, concordance with the Dietary Approaches to Stop Hypertension (DASH), American Cancer Society nutrition guidelines (ACS-score), prudent, and Western dietary patterns was used.

Results

• Extreme scoring group comparisons demonstrated that prediagnosis ACS-score was inversely correlated with all-cause (hazard ratio high v low [HR_HighvLow], 0.78; 95% CI, 0.65 to 0.95) and CRC-specific (HR_HighvLow, 0.74; 95% CI, 0.54 to 1.03) mortality.
• On the other hand, the Western diet score was related to higher all-cause mortality (HR_HighvLow, 1.30; 95% CI, 1.03 to 1.64).
• For postdiagnosis diet, the ACS-score was correlated with lower risk of all-cause (HR_HighvLow, 0.62; 95% CI, 0.47 to 0.83) and CRC-specific (HR_HighvLow, 0.35; 95% CI, 0.17 to 0.73) mortality, the DASH score was inversely related to all-cause (HR_HighvLow, 0.79; 95% CI, 0.62 to 0.99) and CRC-specific (HR_HighvLow, 0.56; 95% CI, 0.35 to 0.89) mortality, and the prudent score was inversely linked to all-cause mortality (HR_HighvLow, 0.72; 95% CI, 0.56 to 0.93).
• Improved DASH (HR, 0.54; 95% CI, 0.31 to 0.92) and prudent (HR, 0.53; 95% CI, 0.29 to 0.95) scores from pre- to postdiagnosis were inversely related to CRC-specific mortality among participants with a low diet quality before diagnosis.