Relationship between SP142 PD-L1 Expression and (18)F-FDG Uptake in Non-Small-Cell Lung Cancer

OBJECTIVES: Immune checkpoint blockers constitute the first-line treatment for advanced non-small-cell lung cancer (NSCLC) with ≥50% PD-L1 expression. In NSCLC, PD-L1 positivity is correlated with high (18)F-fluorodeoxyglucose ((18)F-FDG) uptake. However, these studies only included patients undergoing surgical resection, almost all in their early stages. Moreover, differences in (18)F-FDG uptake between NSCLC with high (≥50%) and low (49%) PD-L1 expression remain unknown. We aimed to investigate the association between metabolic parameter (18)F-FDG uptake and PD-L1 expression status in NSCLC patients. METHODS: From February 2017 to June 2018, 428 consecutive NSCLC patients who underwent (18)F-FDG positron emission tomography/computed tomography (PET/CT) and SP142 PD-L1 expression analysis were retrospectively assessed. The association between clinicopathological characteristics and PD-L1 expression was examined. RESULTS: The frequency of PD-L1-positive tumors was 38.1% (163/428), 28.5% (91/319), and 64.2% (61/95) for NSCLC, adenocarcinoma (ADC), and squamous cell carcinoma (SCC), respectively. Maximal standard uptake (SUVmax) was significantly higher in PD-L1-positive than in PD-L1-negative NSCLC (p < 0.0001), ADC (p < 0.0001), and SCC (p=0.006). SUVmax was significantly higher in NSCLC (p=0.001) and ADC (p=0.003) with high rather than low PD-L1 expression. The receiver operating characteristic curve yielded area under the curve values of 0.726 (95% CI, 0.679–0.774, p < 0.0001), 0.694 (95% CI, 0.634–0.755, p < 0.0001), and 0.625 (95% CI, 0.513–0.738, p=0.044) for NSCLC, ADC, and SCC, respectively. CONCLUSION: (18)F-FDG tumor uptake is strongly, positively correlated with PD-L1 expression in NSCLC and significantly differs between high and low PD-L1-expressing individuals.