Adherence to World Cancer Research Fund/American Institute for Cancer Research Guidelines and Mortality Among Participants with Colorectal Cancer in the MEC Cohort.

BACKGROUND

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

METHODS

We examined the association between post-diagnosis health behavior and mortality in the Multiethnic Cohort (MEC), a diverse group of 215,000 participants from Hawai'i and Los Angeles (recruited 1993-1996). Follow-up was through December 31, 2019. Post-diagnosis health behavior was assessed using a modified World Cancer Research Fund/American Institute of Cancer Research (WCRF/AICR) score (excluding ultra-processed foods). The primary outcome was overall mortality; CRC-specific mortality was secondary.

RESULTS

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

CONCLUSIONS

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

IMPACT

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