Irradiation Dose to the Swallowing Muscles Impacts Nutritional Status in Head and Neck Cancer Patients: The Prospective Randomized HEADNUT Trial

Abstract

To evaluate the influence of radiation dose on swallowing muscles and associated side effects as well as on nutritional status in patients with head and neck cancer undergoing primary or adjuvant (chemo)radiotherapy. Between 2018 and 2020, sixty-one patients were prospectively randomized into the so-called HEADNUT-trial (HEAD and neck cancer patients undergoing NUTritional intervention). Follow-up was continued until 2022. Contouring of the swallowing apparatus included and the swallowing muscles with the superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeal muscle and the inlet of the esophagus. Nutritional status was assessed by bioelectrical impedance analysis (BIA) at the beginning and the end of radiotherapy. The post-therapeutic nutritional status was evaluated by the BIA-derived FFMI (fat-free mass index; kg/m²). Malnutrition was assumed at FFMI values of <15 (♀) and <17 (♂) kg/m². To find differences between dosimetric parameters in well- and malnourished patients, Mann-Whitney-U-test was used. To estimate the relationship between malnutrition and its influencing variables a logistic regression model was built. The following structures differed between well- and malnourished patients at the end of therapy: icm (Dmean, V40Gy (%), V50Gy (%), V60Gy (%)) and cricopharyngeal muscle (V40Gy (%)). After entering these parameters into a multivariable logistic regression model icm Dmean (b = -0.12; Exp(b) = 0.88; 95%-CI: 0.78-1.0; p = 0.06) and icm V40Gy (%) (b = 0.06; Exp(b) = 1.07; 95%-CI: 1-1.13; p = 0.04) proved to be independent predictors of malnutrition. We only determined the cut-off value for icm V40Gy (%) since it was the only parameter which met p<0.05. The optimal cut-off value for the predictor V40Gy (%) based on the Youden Index was 85.6%. Adherence to dose constraints for the swallowing apparatus may prevent malnutrition in head and neck cancer patients at the end of therapy. Specifically, we suggest an icm V40Gy (%) of more than 86% being predictive for nutritional complications.