Longitudinal Associations of Adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Lifestyle Recommendations with Quality of Life and Symptoms in Colorectal Cancer Survivors up to 24 Months Post-Treatment

SIMPLE SUMMARY: Using data from 459 colorectal cancer (CRC) survivors, we described how participants adhered to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations and how this adherence was related to quality of life, level of functioning, symptoms of fatigue, and neuropathy symptoms. We found that increases in a lifestyle score was associated with better physical functioning and less fatigue. No relations with neuropathy symptoms were found. In addition, we observed that physical activity played an important role in the lifestyle score with regards to quality of life. In contrast, we observed that body composition and alcohol recommendations had a counteractive influence within the lifestyle score. Our findings suggest that CRC survivors benefit from overall adherence to the WCRF/AICR lifestyle recommendations in terms of quality of life and fatigue. Specific recommendations have a varying influence on these associations, complicating the interpretation and requiring further study. ABSTRACT: Post-treatment adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations were associated with health-related quality of life (HRQoL), fatigue, and chemotherapy-induced peripheral neuropathy (CIPN) in colorectal cancer (CRC) survivors. In a prospective cohort among CRC survivors (n = 459), repeated home-visits were performed at 6 weeks, 6, 12, and 24 months post-treatment. Dietary intake, body composition, sedentary behaviour, and physical activity were assessed to construct a lifestyle score based on adherence to seven 2018 WCRF/AICR recommendations. Longitudinal associations of the lifestyle score with HRQoL, fatigue, and CIPN were analysed by confounder-adjusted linear mixed models. A higher lifestyle score was associated with better physical functioning and less activity-related fatigue, but not with CIPN. Adjustment for physical activity substantially attenuated observed associations, indicating its importance in the lifestyle score with regards to HRQoL. In contrast, adjustment for body composition and alcohol inflated observed associations, indicating that both recommendations had a counteractive influence within the lifestyle score. Our findings suggest that CRC survivors benefit from an overall adherence to the WCRF/AICR lifestyle recommendations in terms of HRQoL and fatigue, but not CIPN. Specific recommendations have a varying influence on these associations, complicating the interpretation and requiring further study.