Dynamic 18F-FDG Total body PET Imaging as a predictive marker of induction chemo-immunotherapy response in locally advanced non-small cell lung cancer.

Abstract

e20551 Background: The purpose of this study was to evaluate the efficacy of dynamic 18F-FDG total body PET imaging as a predictive maker of induction chemo-immunotherapy response in locally advanced non-small cell lung cancer(NSCLC) by a prospective study. Methods: Stage IIIA-IIIC NSCLC patients were prospectively enrolled in a prospective total body PETCT study ( NCT04654234, GASTO-1067) and a randomized phase II clinical trial ( NCT04085250) between September 2020 and December 2020. All patients underwent a dynamic total-body 18F-FDG PET/CT scan before any treatment and after 2 cycles of induction chemo-immunotherapy (docetaxel+cisplatin+nivolumab). The primary lung tumor, metastatic regional lymph node and inflammatory lymph node before and after treatment were manually delineated by a nuclear medicine physician and a radiation oncologist. Total Body PET was acquired between 0 – 60 mins after the injection of FDG from the subject’s feet. Patients was separated into high dynamic FDG metabolic (H-DFM) group and low DFM(L-DFM) group by the scatter plot of SUV-mean and Ki-mean of primary lung tumor. We compared lesion heterogeneity and different image-derived PET metrics including the metabolic tumor volume(MTV), SUV total lesion glycolysis(SUV-TLG), Patlak-derived influx rate constant (Ki) TLG (Ki-TLG). Results: Fifteen patients were analyzed, 8 patients was in H-DFM group and 7 in L-DFM group. Patients in H-DFM group had significant decreased levels of MTV(p < 0.001), SUV-TLG(p < 0.001) and Ki-TLG(p < 0.001) both in primary lung tumor and metastatic lymph node by the induction chemo-immuotherapy. However, patients in L-DFM group only had a significant reduction of MTV in primary lung tumor(p < 0.05). There was no significant difference in the MTV of metastatic lymph node(p > 0.5), the SUV-TLG(p > 0.5) and Ki-TLG(p > 0.5) of primary lung tumor and metastatic lymph node, before and after induction chemo-radiotherapy. Conclusions: Patients in H-DFM group had the better treatment response of induction chemo-immunotherapy with significant decreased levels of MTV, SUV-TLG and Ki-TLG. Dynamic 18F-FDG Total body PET Imaging could be regard as a potential predictive marker of induction chemo-immunotherapy response in the setting of LA-NSCLC.