Adherence to World Cancer Research Fund/American Institute for Cancer Research Guidelines and Mortality among...

Racial and ethnic minority patients with colorectal cancer are underrepresented in studies on health behavior and mortality.

We examined the association between postdiagnosis health behavior and mortality in the Multiethnic Cohort, a diverse group of 215,000 participants from Hawaii and Los Angeles (recruited 1993-1996). Follow-up was through December 31, 2019. Postdiagnosis health behavior was assessed using a modified World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) score (excluding ultraprocessed foods). The primary outcome was overall mortality, and the secondary outcome was colorectal cancer-specific mortality.

Among 1,079 eligible participants, 489 (45.3%) were women and 850 (78.8%) self-identified as racially/ethnically minoritized people. Over a median follow-up of 12.2 years, there were 613 all-cause deaths and 105 colorectal cancer-related deaths. The median time from diagnosis to questionnaire completion was 5 years (IQR: 2-8). Higher WCRF/AICR scores (4.5-7) were associated with lower risk of overall mortality compared with lower scores [≤2.25; HR = 0.63; 95% confidence interval (CI), 0.45-0.87]. Risk of colorectal cancer-specific mortality was also lower but not statistically significant. Among individual health behaviors, physical activity was associated with lower risk of all-cause and colorectal cancer-specific mortality (reference: <75 minutes/week), with HRs of 0.59 (95% CI, 0.43-0.81) for 75 to <150 minutes/week and 0.51 (95% CI, 0.41-0.64) for ≥150 minutes/week.

Higher adherence to WCRF/AICR guidelines, particularly engaging in moderate-to-vigorous physical activity, was associated with lower risk of mortality in long-term colorectal cancer survivors.

These findings support the generalizability of prior studies examining adherence to WCRF/AICR guidelines to a broader group of patients with colorectal cancer.