Effect of Body Tissue Composition on the Outcome of Patients with Metastatic Non-small Cell Lung Cancer Treated with PD-1/PD-L1 Inhibitors

Obesity and sarcopenia have been reported to affect outcomes in patients with non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs). We analyzed prospective data from 52 patients with non-oncogene driven metastatic NSCLC treated with ICIs. Body tissue composition was calculated by measuring the fat and muscle densities at the level of 3rd lumbar vertebra in each patient computed tomography scan before ICI initiation using sliceOmatic tomovision. We converted the densities to indices [Intramuscular Fat Index (IMFI), Visceral Fat Index (VFI), Subcutaneous Fat Index (SFI), Lumbar Skeletal Muscle Index (LSMI)] by dividing them by height in meters squared. Patients were dichotomized based on their baseline IMFI, VFI and SFI according to their gender-specific median value. The cut-offs that were set for LMSI values were 55 cm2/m2 for males and 39 cm2/m2 for females. SFI distribution was significantly higher (p = 0.040) in responders compared to non-responders. None of the other variables affected response rates. Low LSMI HR: 2.90 (95% CI: 1.261-6.667, p = 0.012) and low SFI: 2.20 (95% CI: 1.114-4.333, p = 0.023) values predicted for inferior OS. VFI and IMFI values did not affect survival. Subcutaneous adipose and skeletal muscle tissue composition significantly affected immunotherapy outcomes in our cohort.