Diet may be associated with survival for patients with colorectal cancer (CRC), according to a study published in the Journal of Clinical Oncology.
In the prospective analysis of pre-CRC diagnosis and post-CRC diagnosis dietary habits among 2801 participants in the Cancer Prevention Study-II Nutrition Cohort, all were free of cancer in 1992-1993 but developed nonmetastatic but invasive CRC by June 2013.
Participant diets (2671 participants at prediagnosis, of whom 1414 died; and 1321 participants at postdiagnosis, of whom 722 died) were scored on scales according to adherence to 4 dietary patterns: American Cancer Society nutrition guidelines (ACS-score), Dietary Approaches to Stop Hypertension (DASH), Western, and prudent diets. Cox proportional hazards models were developed for CRC-specific mortality, cardiovascular (CVD)-specific mortality, other causes of mortality, and all-cause mortality based on diet scores.
Based on prediagnosis diet data, in comparisons of highest vs lowest diet score categories, an association between a higher Western diet score and higher all-cause mortality (hazards ratio [HR] 1.30; 95% CI, 1.03-1.64) was seen, whereas a higher ACS-score was associated with lower all-cause (HR 0.78; 95% CI, 0.65-0.95) and CRC-specific mortality (HR 0.74; 95% CI, 0.54-1.03).
Based on postdiagnosis diet data, in comparisons of highest vs lowest diet score categories, all-cause mortality risk was lower with higher ACS-scores (HR 0.62; 95% CI, 0.47-0.83), prudent scores (HR 0.72; 95% CI, 0.56-0.93), and DASH scores (HR 0.79; 95% CI, 0.62-0.99). CRC-specific mortality was also lower with higher ACS-scores (HR 0.35; 95% CI, 0.17-0.73) and DASH scores (HR 0.56; 95% CI, 0.35-0.89).
CRC-specific mortality was also reduced with improved postdiagnosis prudent (HR 0.53; 95% CI, 0.29-0.95) and DASH (HR 0.54; 95% CI, 0.31-0.92) scores following lower-quality prediagnosis diet.
The authors concluded that both before and after CRC diagnosis, a diet high in plant content and low in animal content may be associated with longer survival.
Guinter MA, McCullough ML, Gapstur SM, Campbell PT. Associations of pre- and postdiagnosis diet quality with risk of mortality among men and women with colorectal cancer [published online October 19, 2018]. J Clin Oncol. doi: 10.1200/JCO.18.00714