The Impact of Dietary Guidance During Cancer Treatment on Quality of Life

Background/Objectives: We examined whether guidance on dietary habits or nutrition-related problems from healthcare professionals during cancer treatment was associated with quality of life, after treatment. Methods: Cross-sectional data were drawn from the Icelandic Compass study, conducted in 2020–2021 among adults diagnosed with cancer in 2015–2019. The analysis included participants who had completed treatment for breast cancer (n = 341), prostate cancer (n = 137), or colorectal cancer (n = 132), for a total sample of 610 participants. Quality of life (QL) was assessed using the EORTC QLQ-C30 global health status/quality of life scale. Associations were examined using regression models adjusted for age, marital status, education, number of cancer treatments, stage at diagnosis, body mass index, tobacco and alcohol use, and comorbidities. Results: Overall, 26% of participants reported receiving sufficient guidance on general dietary habits during treatment and 19% on nutrition-related problems. On average, three years had passed since diagnosis. Among all participants, guidance on general dietary habits was associated with higher QL scores (β = 5.6; 95% CI: 0.8 to 10.5), as was guidance on nutrition-related problems (β = 5.7; 95% CI: 0.3 to 11.1). In subgroup analyses, statistically significant associations were observed among prostate cancer survivors for both dietary guidance (β = 12.4) and guidance on nutrition-related problems (β = 14.0), and among breast cancer survivors for guidance on nutrition-related problems (β = 8.4). Conclusions: Patient-reported sufficient discussions about dietary habits or nutrition-related problems during treatment were associated with slightly higher post-treatment QL scores.