Associations Between Dietary Patterns and Quality of Life in a Longitudinal Cohort of Colorectal Cancer Survivors.

Purpose: To characterize dietary patterns and examine associations with cross-sectional and longitudinal changes in quality of life (QOL) over approximately one year after colorectal cancer (CRC) diagnosis.
Methods: The ColoCare Study is an international, multi-center, prospective cohort study of newly diagnosed CRC survivors of any stage. A subset of participants with CRC in the United States completed patient-reported outcome measures at 6- and 12-months post-enrollment, including the Food Frequency Questionnaire (FFQ) and European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). Dietary patterns at 6 months (around the time of treatment completion) were identified using Principal Component Analysis (PCA) with varimax rotation. Adherence scores were calculated for participants within each dietary pattern, with higher scores indicating higher adherence. Mixed models were used to examine the effect of each dietary pattern on changes in QOL at 6- and 12-month follow-ups, controlling for cancer stage, biological sex, body mass index (BMI), smoking status, and age.
Results: Participants (N = 174) were, on average, 56 ± 14 years old and were mostly female (51.5%), stage III or IV (51.7%), never smokers (60.2%), non-Hispanic (97.1%), and White (83.3%) with a BMI of 27.9 ± 6.1 kg/m ² . PCA revealed two emerging dietary patterns: "Western diet", characterized by processed meats, refined grains, and sugars, and "Prudent diet" characterized by lean proteins, fruits, and vegetables. Higher adherence to a Western diet was associated with worse social functioning at 6-month follow-up (FE = -12.6, p = 0.010). Loss of appetite from 6 to 12 months was associated with higher adherence to both the Western and Prudent dietary patterns (FE = 1.5, p = 0.044; FE = 1.3, p = 0.046, respectively). Neither dietary pattern was associated with global QOL score at 6- or 12-month follow-up ( p 's > 0.05).
Conclusions: Among CRC survivors in the United States, the Western diet was concurrently associated with worse social functioning. Loss of appetite was reported by CRC survivors following both dietary patterns, suggesting that loss of appetite may be a global experience for CRC survivors during this timeframe. Further research is needed to understand specific social challenges experienced by CRC survivors and develop supportive care interventions to address appetite and nutritional concerns.