CT-Derived Body Composition and Early Changes Predict Outcomes of First-Line Chemo-Immunotherapy in Recurrent/Metastatic Nasopharyngeal Carcinoma.

BACKGROUND:Reliable biomarkers for risk stratification and treatment monitoring in recurrent/metastatic nasopharyngeal carcinoma (R/M NPC) treated with first-line chemo-immunotherapy remain limited. This study evaluated the prognostic value of baseline computed tomography (CT)-derived body composition parameters and their early dynamic changes. METHODS:In this single-center retrospective cohort study, patients with R/M NPC receiving first-line chemo-immunotherapy were included. The primary endpoint was progression-free survival (PFS), and secondary endpoints included overall survival (OS), objective response rate (ORR), and disease control rate (DCR). Associations between body composition and outcomes were analyzed. RESULTS:A total of 199 patients were included, and 99 with post-treatment CT after two cycles were further analyzed for dynamic changes. Higher baseline skeletal muscle area (SMA) was independently associated with longer PFS (HR = 0.56, 95% CI: 0.37-0.85, p = 0.006) and OS (HR = 0.46, 95% CI: 0.23-0.93, p = 0.03), and with higher ORR (82.8% vs 70.0%, p = 0.033) and DCR (98.0% vs 91.0%, p = 0.031). During early treatment, a ≤ 1.3% decrease or an increase in SMA was independently associated with longer PFS (HR = 0.53, p = 0.045) and OS (HR = 0.27, p = 0.018). A greater decline in visceral adipose tissue density (ΔVATD < -0.9%) was also associated with more favorable PFS and OS, whereas no significant difference in ORR was observed. CONCLUSION:Baseline SMA and early changes in SMA and VATD have prognostic value in R/M NPC treated with first-line chemo-immunotherapy. CT-based body composition assessment may serve as a practical imaging biomarker for risk re-stratification and individualized management. IMPLICATIONS FOR PRACTICE:CT-based body composition assessment may provide a practical approach for individualized management of patients with recurrent/metastatic nasopharyngeal carcinoma receiving chemo-immunotherapy. Incorporating body composition assessment into routine CT imaging analysis may further improve risk stratification and facilitate early identification of patients with poor prognosis. For patients with low skeletal muscle reserve or significant early muscle loss during treatment, timely nutritional assessment, exercise support, and closer clinical monitoring may be considered to optimize supportive care and treatment management.