Impact of Body Composition on Treatment Toxicity and Outcomes in Patients With Primary Mediastinal Large B-Cell Lymphoma.

Primary mediastinal large B-cell lymphoma (PMBL) is a rare entity that predominantly affects young female patients and typically presents as a large and compressive anterior mediastinal mass. Accumulating evidence suggests relationships among PMBL patient body composition (BC), cancer outcomes, and treatment-related toxicities. The aim of this study was to evaluate the impact of BC on PMBL patients using PET-CT images acquired pretreatment. Two hundred nineteen patients were included in an ancillary analysis of a multicenter retrospective LYSA cohort of treatment-naïve adult PMBL patients who received first-line treatment with ACVBP, CHOP14 or CHOP21 plus anti-CD20. Anthropometric parameters were assessed from the baseline PET-CT image using two methods: (i) manual segmentation at the L3 level and (ii) automatic software-based multislice measurements with Anthropometer3DNet. The median age was 35.4 years (range 18-88 years), and the median body mass index was 23.8 kg/m (15.6; 40.8). Overall, 137 patients were treated with R-ACVBP, 44 received R-CHOP14, and 38 were treated with R-CHOP21. Patients with low lean body mass had a higher incidence of febrile neutropenia, both in the overall cohort (25% vs. 12.6%, p = 0.02) and in the R-ACVBP subgroup (35.7% vs. 19.4%, p = 0.03). Univariate analysis showed that in patients treated with R-ACVBP, subcutaneous low adiposity, determined by 3D measurements, was associated with overall survival (OS) (p = 0.04). At 3 years, the OS (95% CI) was 96% (93-100) in above-median adiposity patients and 86% (78-95) in below-median adiposity patients. Low lean body mass (LBM), assessed from the pretreatment PET-CT images using automatic Anthropometer3DNet software, may serve as a predictive marker for acute treatment-related toxicity in PMBL patients, particularly those receiving the dose-intensive R-ACVBP regimen. Additionally, depletion of the subcutaneous fat mass was correlated with an increased risk of mortality, highlighting the importance of a comprehensive BC assessment in this patient population.