Prognostic Value of Treatment-Related Body Composition Changes in Metastatic NSCLC Receiving Nivolumab.

Baseline sarcopenia was present in approximately one-third of metastatic NSCLC patients treated with nivolumab.

• 34.1% (n = 30) of 88 patients were classified as sarcopenic at baseline.
• The study cohort consisted of 88 metastatic NSCLC patients initiated on nivolumab between January 2022 and December 2024.
• Body composition was derived from 18F-FDG PET/CT scans at the L3 level.
• Parameters included psoas muscle index (PMI), skeletal muscle index (SMI), intramuscular adipose content (IMAC), and subcutaneous fat density (SFD).

Non-sarcopenic patients had significantly longer median overall survival than sarcopenic patients.

• Median OS was 19 months in non-sarcopenic patients versus 5 months in sarcopenic patients.
• The difference was statistically significant (p < 0.001).
• Survival analyses were performed using Kaplan-Meier estimates and Cox regression models.

In univariate analysis, multiple baseline and treatment-related factors were associated with overall survival.

• Factors associated with OS in univariate analysis included older age, higher comorbidity burden, liver metastasis, and baseline sarcopenia.
• Adverse treatment-related changes in muscle and nutritional parameters were also associated with OS in univariate analysis.
• The study was retrospective in design.

In multivariate analysis, only unfavorable changes in skeletal muscle index and subcutaneous fat radiodensity remained independent adverse prognostic factors for overall survival.

• Unfavorable change in skeletal muscle index (ΔSMI) had a hazard ratio of 3.39 (p = 0.003).
• Unfavorable change in subcutaneous fat radiodensity (ΔSFD) had a hazard ratio of 2.45 (p = 0.02).
• Baseline body composition parameters did not maintain their independence in multivariate models.
• Changes were evaluated between baseline and 3-month 18F-FDG PET/CT scans.

Dynamic treatment-related body composition changes were more strongly predictive of overall survival than static baseline measurements in nivolumab-treated NSCLC patients.

• Muscle loss or insufficient gain during treatment was an independent adverse prognostic factor.
• Unfavorable changes in subcutaneous fat radiodensity during treatment were an independent adverse prognostic factor.
• Baseline body composition parameters lost prognostic independence in multivariate analysis.
• The authors conclude that monitoring dynamic body composition throughout treatment is clinically important, 'rather than static assessments, in NSCLC patients receiving immunotherapy.'