Dietary changes in head and neck cancer patients pre- and post-chemotherapy and/or radiation therapy.

e24126 Background: Head and neck squamous cancer (HNSCC) patients often face challenges with adequate nutritional intake due to the location of their disease and treatment-related adverse effects. As many as 60% of HNSCC patients present with malnutrition at diagnosis due to tumor location and burden. Currently, there are no specific nutrient guidelines for HNC patients. This study aimed to examine changes in nutrient intake and diet quality in patients with HNSCC before and after completion of radiation therapy (RT) or chemoradiation (CRT). Methods: This study used data from an ongoing longitudinal observational study that included newly diagnosed HNSCC patients receiving RT or CRT at Emory Winship Cancer Institute and MD Anderson Cancer Center. Adults aged ≥ 21 years with non-recurrent, non-metastatic HNSCC were enrolled. Dietary intake was assessed using the Automated Self-Administered 24-Hour Dietary Assessment Tool (ASA24) before treatment initiation and one-month post-treatment. Two dietary interviews were completed at each time point and averaged to estimate nutrient intake using the USDA Food and Nutrient Database and diet quality using Healthy Eating Index-2020 (HEI) scores. Macronutrients were expressed as % of kcal, and other nutrients were energy-adjusted per 1000 kcal. Linear mixed models assessed pre- to post-treatment changes, adjusting for age, BMI, sex, HPV status, treatment, and time, with false discovery rate (FDR) correction for multiple testing. Results: Among the 103 patients analyzed, 83.3% were male, with a mean age of 59.2 yrs (SD = 10.5 yrs). 76.5% were HPV positive, and 66.7% received CRT. Pre-treatment, the mean BMI was 29.4 kg/m 2 (SD = 6.43 kg/m 2 ); the mean total energy intake was 2010 kcal/day (SD = 752 kcal/day), and the mean HEI total score was 48.0 (SD = 48.5). Overall, total energy intake did not change significantly pre- and post-treatment (FDR = 0.198). However, there was a decrease in % kcal from total fat (FDR < 0.01), solid fats (FDR = 0.0144), saturated fat (FDR < 0.01), and monounsaturated fat (FDR = 0.0154). Additionally, % kcal from carbohydrates increased (FDR < 0.01). For micronutrients, iron, Vitamin B1, Vitamin B2, Vitamin B6, Vitamin B9, Vitamin B12, Vitamin D, magnesium, and calcium intake all significantly increased (all FDR < 0.05). Total HEI score did not significantly change (FDR = 0.813), but whole fruit (FDR = 0.013) and total fruit (FDR < 0.01) intake significantly decreased. Conclusions: Despite stable energy intake and diet quality, treatment was associated with decreased fat and fruit intake and increased carbohydrate and certain micronutrient intake. These changes in diet could be attributed to treatment side effects, which can alter food preferences. Further research is warranted to examine the association between treatment side effects and nutritional intake. The findings may inform the development of clinical nutrition guidelines for HNSCC patients.