Predicting survival in non-small cell lung cancer treated with nivolumab: the role of spleen and bone marrow 18 F-FDG PET/CT parameters

Abstract

Objective: Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) may provide prognostic information in patients with non-small cell lung cancer (NSCLC) receiving immunotherapy. We investigated the predictive value of spleen and bone marrow metabolic parameters on 18F-FDG PET/CT for response to nivolumab, progression-free survival (PFS), and overall survival (OS) in stage IV NSCLC. Methods: Selected metabolic parameters of the spleen (such as baseline/post-treatment total spleen glycolysis [TSG]) and bone marrow (baseline and post-treatment standardized uptake values [SUVs]) were retrospectively evaluated on baseline and post-treatment PET/CT scans in 61 patients. The effects of all parameters on PFS and OS were examined. Results: Baseline spleen and bone marrow metabolic parameters did not differ significantly between responders and non-responders to nivolumab. The median OS was longer for patients with lower post-treatment TSG (27.0 vs. 19.6 months, p = 0.036) and baseline spleen volume (26.9 vs. 18.2 months, p = 0.022). The median OS was longer in patients whose post-treatment bone marrow SUVmean (25.3 vs. 15.7 months, p = 0.007) and spleen-to-liver SUVmax ratio (SLR_SUVmax) were lower than their baseline values (25.1 vs. 18.3 months, p = 0.043). Baseline spleen volume was the only independent predictor of PFS (hazard ratio [HR] = 1.02, p = 0.039). Age (≥ 70 years) (HR = 1.08, p = 0.019), baseline neutrophil-to-lymphocyte ratio (HR = 1.42, p = 0.012), and post-treatment decreases in bone marrow SUVmean (HR = 0.12, p = 0.001) and SLR_SUVmax (HR = 0.16, p = 0.042) from baseline were independent predictors of OS. Conclusions: Splenic glucose metabolism, baseline spleen volume, and bone marrow glucose metabolism were associated with survival after nivolumab in patients with metastatic NSCLC. Baseline spleen volume was the only independent predictor of PFS. Age, baseline neutrophil-to-lymphocyte ratio, and decreased bone marrow SUVmean and SLR_SUVmax after nivolumab were identified as independent predictors of OS.