Healthy diet may reduce risk for death among patients with colorectal cancer
Individuals with colorectal cancer who followed healthy diets before and after diagnosis demonstrated a reduced risk for death from the disease or any cause, according to results of a study published in Journal of Clinical Oncology.
“This study is the first to our knowledge that considered change in diet quality across the [colorectal cancer] continuum,” researcher Mark A. Guinter, PhD, MPH, postdoctoral fellow in cancer prevention at American Cancer Society, said in a press release. “These results suggest that high diet quality after diagnosis, even if poor before, may be associated with a lower risk of death.”
There are more than 1.4 million colorectal cancer survivors in the United States.
Previous studies have shown diet quality can have a large influence on disease outcomes and that some dietary components are linked to survival among individuals with colorectal cancer.
Guinter and colleagues reviewed data from 2,801 participants in the prospective Cancer Prevention Study-II Nutrition Cohort. All individuals were cancer free at baseline in 1992-1993 and subsequently were diagnosed with invasive, nonmetastatic colorectal cancer.
Mean ages were 64 years (standard deviation [SD], 5.8 years) at baseline and 73 years (SD, 7 years) at diagnosis.
The majority (75.3%) of tumors were in the colon, and more were localized (n = 1,407) than regional (n = 1,394).
Prediagnosis diet data were available for 2,671 people in the cohort, and postdiagnosis data were available for 1,321 of them.
The average time from completion of the baseline food frequency questionnaire to colorectal cancer diagnosis was 9 years.
Investigators evaluated diets based on concordance with Dietary Approaches to Stop Hypertension (DASH), American Cancer Society guidelines on nutrition and physical activity for cancer prevention (ACS score), and prudent and Western dietary patterns.
Extreme scoring group comparisons showed prediagnosis ACS score was inversely associated with all-cause mortality (HR = 0.78; 95% CI, 0.65-0.95) and colorectal cancer-specific mortality (HR = 0.74; 95% CI, 0.54-1.03). A prediagnosis Western diet — characterized by high amounts of red meat and other animal products — was associated with higher all-cause mortality (HR = 1.3; 95% CI, 1.03-1.64).
For postdiagnosis diet, ACS score was associated with lower risk for all-cause mortality (HR = 0.62; 95% CI, 0.47-0.83) and colorectal cancer-specific mortality (HR = 0.35; 95% CI, 0.17-0.73). DASH score was inversely associated with all-cause mortality (HR = 0.79; 95% CI, 0.62-0.99) and disease-specific mortality (0.56; 95% CI, 0.35-0.89). Prudent dietary patterns were inversely associated with all-cause mortality (HR = 0.72; 95% CI, 0.56-0.93).
Dietary improvements after diagnosis also appeared to decrease risk for death. Among those with poor diet quality before diagnosis, improved DASH (HR = 0.54, 95% CI, 0.31-0.92) and prudent dietary patterns (HR = 0.53; 95% CI, 0.29-0.95) between the prediagnosis and postdiagnosis periods were inversely associated with colorectal cancer-specific mortality.
After diagnosis, patients with the highest ACS score demonstrated a 65% reduced risk for colorectal cancer death and a 38% reduced risk for death from any cause compared with those who had the lowest ACS score.
“Dietary patterns reflective of high intakes of plant foods and low intakes of animal products before and after colorectal cancer diagnosis are associated with longer survival,” Guinter and colleagues wrote. “[This] suggests the importance of diet quality as a potentially modifiable tool to improve prognosis among men and women with colorectal cancer.” – by John DeRosier
Disclosures: This study was supported by American Cancer Society’s Cancer Prevention Studies Postdoctoral Fellowship Program and funded by the American Cancer Society. The authors report no relevant financial disclosures.