Role of body composition and metabolic parameters extracted from baseline 18F-FDG PET/CT in patients with diffuse large B-cell lymphoma.

This study aimed to clarify the clinical and prognostic role of body composition and metabolic parameters extracted from baseline 18F-FDG PET/CT in patients with diffuse large B-cell lymphoma (DLBCL). We retrospectively collected the clinicopathological and 18F-FDG PET/CT parameters of 181 DLBCL patients. The indexes of skeletal muscle, subcutaneous adipose tissue, and visceral adipose tissue were calculated using the area measured at the 3rd lumbar level normalized for height. Additionally, the metabolic activity of corresponding muscle and adipose tissue, and maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of all lesions were measured. Survival endpoints included progression-free survival (PFS) and overall survival (OS). We identified 75 (41.4%) patients with low skeletal muscle index (sarcopenia), presenting risk factors including male, high β2-microglobulin, low BMI, high visceral adipose tissue index, low SUVmax of skeletal muscle, and high SUVmax of visceral adipose tissue. Male, low BMI, low visceral adipose tissue index, and high SUVmax of subcutaneous adipose tissue were risk factors for low subcutaneous adipose tissue index diagnosed in 105 (58.0%) patients. In total, 132 (79.2%) patients represented low visceral adipose tissue index, associated with younger age, B symptoms, and low BMI. Eastern Cooperative Oncology Group (ECOG) status, sarcopenia, and visceral adipose tissue index were found independently predictive of PFS and OS, while β2-microglobulin was independently predictive of OS. In conclusion, body composition indexes were correlated with both clinical characteristics and 18F-FDG PET/CT metabolic parameters, significantly impacting survival, such that sarcopenia and high visceral adipose tissue index were powerful predictors of poor DLBCL outcomes.