Abstract 5166: Blood-based biomarker analysis for predicting efficacy of definitive concurrent chemoradiotherapy and durvalumab consolidation in patients with unresectable locally advanced non-small cell lung cancer

Abstract

Abstract Background: This study aimed to investigate the feasibility of using circulating tumor cells (CTCs) and peripheral blood cells (PBCs) as biomarkers for predicting the efficacy of concurrent chemoradiotherapy (CCRT) and durvalumab consolidation (DC) in patients with locally advanced non-small cell lung cancer (NSCLC). Methods: We recruited patients diagnosed with unresectable stage III NSCLC who received definitive CCRT between March 2020 and March 2021. DC was permitted in patients who did not progress after CCRT and tumor PD-L1 ≥1%. Blood samples were collected before (C0) and after CCRT (C1) to calculate PBC counts and analyze CTCs. CTCs, isolated using CD-PRIME࣪ system, exhibited EpCAM/CK+/CD45− phenotype in BioViewCCBS࣪. Results: A total of 50 patients were enrolled and 23 patients received DC. The median duration of follow-up was 16.3 months, and the median progression-free survival (PFS) was not significantly different between patients with and without DC (13.1 vs. 13.5 months; p=0.355). In overall, patients with higher platelets (PLThi, >252x103/uL) at C1 had worse median PFS than those with lower platelets (PLTlo, ≤252x103/uL) (5.9 vs. 15.1 months; p<0.001). In DC group, patients with residual CTC clusters after CCRT (C1) had worse median PFS than those without detectable CTC cluster (9.5 vs. not reached; p=0.034). In multivariate analysis, PLThi at C1 was an independent factor for PFS (hazard ratio [HR] 4.12, 95% confidence interval [CI] 1.77-9.61; p=0.001), and patients with DC who had PLThi and residual CTC clusters at C1 showed the worst PFS (2.6 months, HR 44.40; p=0.001), even worse than those without DC who had PLThi (5.9 months, HR 15.65; p=0.002). Conclusions: Comprehensive analysis of CTC and PBC counts before and after CCRT, especially CTC clusters and platelets at C1, demonstrated they might be biomarkers for predicting survival. This finding could aid in risk stratification of patients with unresectable stage III NSCLC who are eligible for DC after definitive CCRT. Citation Format: Cheol-Kyu Park, Hwa-Kyung Park, Hyung-Joo Oh, Hyun-Ju Cho, In-Jae Oh, Young-Chul Kim. Blood-based biomarker analysis for predicting efficacy of definitive concurrent chemoradiotherapy and durvalumab consolidation in patients with unresectable locally advanced non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5166.