Dynamic 18F-FDG Total Body PET Imaging as a Predictive Marker of Induction Chemo-Immunotherapy Followed by Concurrent Chemoradiotherapy Response in Locally Advanced Non-Small Cell Lung Cancer

Purpose/Objective(s)

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 followed by concurrent chemoradiotherapy (CCRT) response in locally advanced non-small cell lung cancer (LA-NSCLC) by a prospective study.

Materials/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. Patients underwent a dynamic total-body 18F-FDG PET/CT scan before any treatment, after 2 cycles of induction chemo-immunotherapy (docetaxel + cisplatin + nivolumab), then after CCRT. 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 baseline scan for 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 completed three scans (before treatment, after induction chemo-immunotherapy, after CCRT). Eight patients were in H-DFM group and 7 in L-DFM group by baseline scan. 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-immunotherapy and CCRT. 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 during the treatment course in L-DFM group.

Conclusion

Patients in H-DFM group had the better treatment response of induction chemo-immunotherapy and CCRT with significant decreased levels of MTV, SUV-TLG and Ki-TLG. Dynamic ¹⁸F-FDG Total body PET Imaging could be regarded as a potential predictive marker of induction chemo-immunotherapy and CCRT response in the setting of LA-NSCLC.