2506 - Enhanced Survival in Stage IV NSCLC Patients: A Comparison of Sequential vs. Concurrent Radiotherapy Combined with Immunotherapy
Presenter(s)
Y. Wang1, J. Wang2,3, Y. Zhang4, J. Liu2,5, C. Tian2, S. Bao2,6, J. Ma2, F. Wang2, J. Zhang7, and D. Chen2,5; 1Shandong Provincial Key Laboratory of Precision Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical-Sciences, Jinan, Shandong, China, 2Shandong Provincial Key Laboratory of Precision Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, 3School of Clinical Medicine,Shandong Second Medical University, Weifang, China, 4Xijing Hospital, Fourth Military Medical University, Xian, China, 5Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, 6Shandong University Cancer Center, Shandong University, Jinan, China, 7Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
Purpose/Objective(s): Immunotherapy combined with radiotherapy (IRT) demonstrates significant synergistic effects and has been extensively implemented in the management of stage IV non-small cell lung cancer (NSCLC). However, the optimal sequencing of IRT remains controversial in the treatment paradigm for stage IV NSCLC. This study aimed to evaluate whether different treatment sequences of IRT lead to differential survival outcomes among patients diagnosed with stage IV NSCLC.
Materials/Methods: This study enrolled patients with stage IV NSCLC who underwent IRT. Based on the sequence of IRT administration, participants were stratified into three distinct groups: Immunotherapy(IO)-before-radiotherapy(RT), RT-before-IO, and concurrent immunotherapy and radiotherapy (cIRT). Notably, all patients remained free from disease progression during the treatment interval. The primary endpoint was progression-free survival (PFS), while overall survival (OS) served as the secondary endpoint. Survival outcomes were evaluated using Kaplan-Meier analysis, and Cox proportional hazards regression models were used to identify independent prognostic factors associated with PFS and OS.
Results: In this study, 303 patients with stage IV NSCLC were enrolled and stratified into three treatment groups based on the IRT sequence: 111 patients in the IO-before-RT group, 75 patients in the RT-before-IO group, and 117 patients in the cIRT group. Compared with the cIRT group, the IO-before-RT group demonstrated significantly superior in prolonging patients' PFS (P < 0.0001) and OS (P = 0.0002). The RT-before-IO group was also significantly better than the cIRT group in improving patients' PFS (P < 0.0001) and OS (P = 0.0123). However, no statistically significant differences in PFS (P = 0.9749) and OS (P = 0.3417) were observed between the IO-before-RT and RT-before-IO groups. Multivariate analysis validated the sequence of IRT administration as an independent prognostic factor. And multivariate analysis showed that high PD-L1 expression (=50%) was an independent favorable prognostic factor for PFS in advanced NSCLC patients undergoing combined IRT (HR = 0.422, P = 0.003).
Conclusion: Although the efficacy of IO-before-RT and RT-before-IO was comparable, IO-before-RT and RT-before-IO demonstrated more advantages in terms of PFS and OS compared with concurrent IRT in patients with stage IV NSCLC.