Can a Healthier Diet Affect Survival in Patients With Metastatic Colorectal Cancer?

A prospective study examining links between diet quality and survival of patients with metastatic colorectal cancer (CRC) found no link between diet at the initiation of first-line treatment and overall survival.

For the study, Erin Van Blarigan, ScD, of the University of California San Francisco, and colleagues assessed “validated food frequency” questionnaires completed by 1,284 of 2,334 patients (55.0%) with metastatic CRC enrolled in the Cancer and Leukemia Group B (Alliance)/Southwest Oncology Group 80405 trial. The results, published online in JAMA Network Open, found no significant association in overall survival and any of five dietary patterns:

  • Alternative Healthy Eating Index (AHEI), which is scored from 0 to 110 and is based on vegetables (excluding potatoes), fruits, whole grains, nuts and legumes, long-chain n-3 fatty acids, polyunsaturated fatty acids, sweetened beverages and juice, red and processed meat, trans fat, sodium, and alcoholic drinks
  • Alternative Mediterranean Diet (AMED), which is scored from 0 to 9 and is based on vegetables, fruits, nuts, whole grains, legumes, fish, ratio of monounsaturated to saturated fat, red and processed meat, and alcohol
  • Dietary Approaches to Stop Hypertension (DASH) diet, which is scored from 0 to 45 and is based on fruits, vegetables, nuts and legumes, low-fat dairy, whole grains, sodium, sweetened beverages, red and processed meats, and sweets and desserts
  • The Western dietary pattern, characterized by higher intake of dairy, refined grains, condiments, red meat, and sweets and desserts

“Making lifestyle changes is hard, especially when you are dealing with cancer diagnosis and treatment,” Van Blarigan told MedPage Today. “Patients may wish to focus their energy on making changes that are most likely to be helpful. Data on diet and exercise in people with metastatic colorectal cancer are very limited, but the information we have right now suggests that patients should really prioritize exercise during and after their cancer treatments.”

Overall, none of the diet scores or patterns examined were associated with survival in metastatic CRC, the investigators reported. “We observed an inverse association between the AMED score and risk of death (HR quintile 5 [Q5] vs quintile 1 [Q1] 0.83, 95% CI 0.67-1.04, P=0.04 for trend), but point estimates were not statistically significant. Additionally, the Western diet pattern was associated with longer survival in individuals with KRAS variant tumors (HR Q5 vs Q1 0.50, 95% CI 0.32-0.77) but not those with wild-type tumors (HR Q5 vs Q1 0.95, 95% CI 0.68-1.33, P=0.02 for interaction).”

“None of the other diet scores or patterns were associated with survival, overall or in subgroups, and the results did not change when patients who died within 90 days after administration of the [questionnaire] were excluded,” the team noted.

Writing in an accompanying commentary, Cindy Kin, MD, MS, of Stanford University School of Medicine in California, pointed out that although a Western diet, high in red meat and saturated fats, has been linked to the development of colorectal cancer, the new study addresses the less well-studied area of diet quality and outcomes in CRC, particularly for those with

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