Molecular imaging research on 18F-FDG PET/CT and biomarker analysis to predict the efficacy of neoadjuvant camrelizumab combined with chemotherapy for resectable stage IIIA-IIIB NSCLC.

Abstract

e15065 Background: The purpose of this study was to explore the predictive value of tumor and secondary lymphoid metabolic parameters on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and circulating biomarkers for pathological response of neoadjuvant camrelizumab combined with chemotherapy in patients with non-small cell lung cancer (NSCLC). Methods: We included 22 patients who was diagnosed with NSCLC (stage IIIA-IIIB (T3-4N2)) and underwent curative surgery after receiving 3 cycles of camrelizumab plus chemotherapy between January 2023 and January 2024 in Shandong Cancer Hospital. Radical surgery was performed within 4-6 weeks after neoadjuvant therapy. Patients undergo 18F-FDG PET/CT scans in 1 week before treatment and 1 week before surgery. Pathological outcomes were assessed and divided into pathologic complete response (pCR) and non-pCR (defined as residual tumor > 0%). The PET/CT parameters were measured, including tumor metabolic parameters such as maximum normalized uptake value (SUVmax), average normalized uptake value (SUVmean), total pathological glycolysis (TLG), and metabolic tumor volume (MTV). Additionally, secondary lymphoid organ metabolic parameters like the spleno-liver SUVmax ratio (SLR) and bone marrow-liver SUVmax ratio (BLR) were assessed. Furthermore, lymphocyte subsets and inflammatory biomarkers in peripheral blood were analyzed. The correlation between PET/CT metabolic parameters, lymphocyte subsets, inflammatory biomarkers and pathological response was analyzed. Results: pCR was achieved in 8 of the 22 patients. SUVmax in both pCR (p<0.001) and non-pCR patients (p<0.001) decreased before surgery. Among patients with pCR, the absolute value of decreased SUVmax (p = 0.024) and the rate of decreased SUVmax (ΔSUVmax%) (p = 0.042) before surgery was higher than those in non-pCR patients. In pCR group, SLR has a decreasing trend before surgery (p = 0.083). In circulating biomarker analysis, the percentage of NK cells changes (ΔNK%) of patients with pCR before surgery was higher than that of patients with non-pCR (p = 0.029). Neutrophil-to-lymphocyte ratio (NLR) in pCR group decreased significantly (p = 0.021) before surgery and there also had declining trend in the non-pCR group (p = 0.062). Before surgery, systemic immune-inflammation index (SII) was significantly decreased in both pCR (p = 0.028) and non-pCR (p<0.001) groups. There also had significant decrease in derived neutrophil-to-lymphocyte ratio (dNLR) before surgery in both pCR (p = 0.01) and non-pCR (p = 0.031) groups. Conclusions: The SUVmax of the primary site at baseline, ΔSUVmax% and ΔNK% have good value in pCR for patients with stage IIIA-IIIB NSCLC receiving neoadjuvant camrelizumab combined with chemotherapy. More analysis of biomarkers is ongoing.