Association between metabolic status and nivolumab efficacy in metastatic non-small cell lung cancer: Focus on resting energy expenditure

<b>Objective:</b> Non-small cell lung cancer (NSCLC) is a common and deadly cancer, and predicting survival can be useful for guiding treatment. This study aimed to investigate the impact of metabolic status-specifically resting energy expenditure (REE)-and clinicopathological characteristics on survival outcomes in patients with metastatic NSCLC receiving nivolumab as second-line therapy following platinum-based chemotherapy. <b>Methods:</b> This prospective, non-interventional, observational, single-center study included 148 adult patients with metastatic NSCLC receiving nivolumab as second-line treatment. Demographic data, cancer diagnosis-related characteristics, laboratory parameters, measured REE (mREE), and predicted REE (pREE) were recorded just before nivolumab treatment was initiated. <b>Results:</b> The mean ages of non-hypermetabolic and hypermetabolic patients were 63 ± 8 and 64 ± 9, respectively. Weight, height, BMI, and pREE were significantly higher in the non-hypermetabolic group. In the hypermetabolic group, the incidence of brain metastasis and the mREE were significantly higher. The median progression-free survival (PFS) and overall survival (OS) were 5.3 and 15.8 months, respectively. Multivariate analysis identified several predictors of survival. Poor ECOG performance status (PS) (<i>p</i> < 0.001), liver metastases (<i>p</i> = 0.018), and mREE/pREE ratio > 120% (<i>p</i> = 0.005) were significantly associated with shorter PFS. Similarly, poor ECOG PS (<i>p</i> = 0.037), liver metastases (<i>p</i> = 0.041), and mREE/pREE ratio > 120% (<i>p</i> = 0.009) were also linked to reduced OS. <b>Conclusions:</b> In patients with NSCLC treated with nivolumab, poor ECOG PS, the presence of liver metastases, and an mREE/pREE ratio > 120% were associated with poorer survival outcomes. Further prospective multicenter studies are required to validate these findings.