Influence of fat-free mass index on the survival of patients with head and neck cancer

Purpose: To determine whether muscle mass, defined by fat-free mass index (FFMI) measured with bioelectrical impedance analysis (BIA), is predictive of survival of head and neck squamous cell carcinoma (HNSCC) patients. Methods: HNSCC patients treated between 2014 and 2018 at the Department for Nutrition of the Institute of Oncology Ljubljana were reviewed. The FFMI values from the pretreatment BIA measurements and pretreatment body mass index (BMI) were used to categorize patients into groups with low and normal muscle mass and BMI using the Global Leadership Initiative on malnutrition (GLIM) recommended cutoff values. The impact of FFMI on disease-free survival (DFS) and overall survival (OS) was determined. Results: Of the 71 included patients, 31 (43.7%) had normal FFMI, and 40 (56.3%) had low FFMI, whereas 44 (62%) and 27 (38%) of the patients had normal and low BMI, respectively. Between FFMI and BMI values, a significant correlation was found (R = 0.75, p < 0.001). Univariate regression analysis showed that FFMI (as a continuous variable) was of prognostic significance for OS (p = 0.039), which was confirmed by multivariate regression analysis (p = 0.029). The model where BMI replaced FFMI negated the prognostic value of BMI (as a continuous variable). Neither FFMI nor BMI was found to be a predictor of DFS on univariate or multivariate analysis. Conclusions: In the present group of HNSCC patients, low FFMI adversely influenced OS, emphasizing the importance of using body composition measurement over BMI alone for pretreatment nutritional evaluation of these patients.