The prognostic value of sarcopenia and sarcopenic obesity in patients with lung cancer receiving immunotherapy: a propensity score matching study.

Background: Sarcopenic obesity (SO) is a prognostic factor and its impact on response to immunotherapy is still unknown in lung cancer. We aimed to explore the role of SO and body composition in predicting overall survival (OS) in patients with lung cancer receiving immune checkpoint inhibitors (ICIs).

Methods: We conducted a retrospective study involving 119 patients with lung cancer who underwent immunotherapy. The subcutaneous fat area (SFA), visceral fat area (VFA) and skeletal muscle index (SMI) were determined by the cross-sectional computed tomography at the L3 lumbar vertebral level. Sarcopenia and SO were defined by SMI and body mass index. Kaplan-Meier and Cox proportional hazard analyses were used to evaluate the impact of body composition on survival. The propensity score matching (PSM) analysis was used to reduce bias and a nomogram was created to predict the OS.

Results: The Kaplan-Meier survival showed that patients with sarcopenia and SO had poor survival time in the total and PSM cohort. The Cox analyses revealed that sarcopenia (Hazard ratio (HR): 2.04, 95% Confidence Interval (CI): 1.04-4.01, P = 0.039) and SO (HR: 3.17, 95%CI: 1.49-6.75, P = 0.003) were independent OS predictors. SFA and VFA were not associated with OS. The SMI, age, stage, albumin level and SFA were used to develop a nomogram. Patients with high nomogram scores had worse OS (P < 0.0001).

Conclusions: Sarcopenia and SO are prognostic factors in patients with lung cancer receiving ICIs. A nomogram that integrates body composition is sufficiently accurate for predicting OS in patients with lung cancer receiving immunotherapy.