Evaluation of Sarcopenia and Prognostic Biomarkers in Stage III Non-Small Cell Lung Cancer Turkish Oncology Group and Turkish Society of Radiation Oncology Thoracic Cancer Study Group (08-005)

Abstract Objectives: The aim of this retrospective multicenter study was to evaluate the prognostic significance of sarcopenia, prognostic nutritional index (PNI), and inflammatory markers in patients with stage III non-small cell lung cancer (NSCLC) who received definitive chemoradiotherapy. Furthermore, the study aimed to determine the threshold value of disease-specific sarcopenia. Methods: A total of 461 patients with stage III NSCLC were evaluated. Sarcopenia, PNI, and biochemical inflammatory markers were assessed. Kaplan-Meier method and Cox regression analysis were used to analyze overall survival (OS) and progression-free survival (PFS). Results: This study found a disease-specific sarcopenia threshold of LSMI <38.7 cm² / m² for women and <45.1 cm² / m² for men, with 25.2% of patients having disease-specific sarcopenia. The optimal PNI cut-off value was determined to be 34.71, with 75.3% of patients categorized as PNI-high and 24.7% as PNI-low. Multivariate cox regression analysis revealed that low PNI was found to be an independent unfavorable prognostic factor for both PFS (HR =0.67; 95% CI, 0.48-0.92, p= 0.015) and OS (HR =1.49; 95% CI, 1.11-2.01, p= 0.008). Other factors including ECOG PS 3 (HR =7.76; 95% CI, 1.73-34.76, p=0.007), induction CT (HR =0.66; 95% CI, 0.49-0.88, p= 0.004), and disease-specific sarcopenia (HR =1.40; 95% CI, 1.02-1.92, p= 0.038) also had independent effects on prognosis. Conclusion: The present study provides evidence that the presence of sarcopenia and low PNI significantly impacts the prognosis of patients with stage III NSCLC who undergo definitive CRT. Furthermore, our study is notable for being the first multicenter investigation to identify a disease-specific sarcopenia threshold.