Predicting treatment outcomes using <sup>18</sup> F-FDG PET biomarkers in patients with non-small-cell lung cancer receiving chemoimmunotherapy
Chang Gon Kim, Sang Hyun Hwang, Kyung Hwan Kim, Hong In Yoon, Hyo Sup Shim, Ji Hyun Lee, Yejeong Han, Beung‐Chul Ahn, Min Hee Hong, Hye Ryun Kim, Byoung Chul Cho, Arthur Cho, Sun Min Lim
Abstract
Background: Predictive markers for treatment response and survival outcome have not been identified in patients with advanced non-small-cell lung cancer (NSCLC) receiving chemoimmunotherapy. We aimed to evaluate whether imaging biomarkers of 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) and routinely assessed clinico-laboratory values were associated with clinical outcomes in patients with advanced NSCLC receiving pembrolizumab plus platinum-doublet chemotherapy as a first-line treatment. Methods: We retrospectively enrolled 52 patients with advanced NSCLC who underwent baseline 18 F-FDG PET/CT before treatment initiation. PET/CT parameters and clinico-laboratory variables, constituting the prognostic immunotherapy scoring system, were collected. Optimal cut-off values for PET/CT parameters were determined using the maximized log-rank test for progression-free survival (PFS). A multivariate prediction model was developed based on Cox models for PFS, and a scoring system was established based on hazard ratios of the predictive factors. Results: During the median follow-up period of 16.7 months (95% confidence interval: 15.7–17.7 months), 43 (82.7%) and 31 (59.6%) patients experienced disease progression and death, respectively. Objective response was observed in 23 (44.2%) patients. In the multivariate analysis, maximum standardized uptake value, metabolic tumour volume 2.5 , total lesion glycolysis 2.5 , and bone marrow-to-liver uptake ratio from the PET/CT variables and neutrophil-to-lymphocyte ratio (NLR) from the clinico-laboratory variables were independently associated with PFS. The scoring system based on these independent predictive variables significantly predicted the treatment response, PFS, and overall survival. Conclusion: PET/CT variables and NLR were useful biomarkers for predicting outcomes of patients with NSCLC receiving pembrolizumab and chemotherapy as a first-line treatment, suggesting their potential as effective markers for combined PD-1 blockade and chemotherapy.