2627 - Impact of Thoracic Radiotherapy on Survival Outcomes in Extensive-Stage Small Cell Lung Cancer with Brain Metastases: A Multicenter Retrospective Study
Presenter(s)
B. Li1, X. Fan1, T. Dong2, C. Jiang3, and L. Wang4; 1Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, 2Department of Obstetrics and Gynecology, Qilu Hospital of Shandong University, Jinan, Shandong, China, 3Department of Otorhinolaryngology & Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China, 4Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China, Jinan, Shandong, China
Purpose/Objective(s): Chemoimmunotherapy has been established as the first-line standard treatment for extensive-stage small-cell lung cancer (ES-SCLC), with the addition of thoracic radiotherapy (TRT) conferring further survival benefits. Notably, the brain was one of the major target organs of metastasis, with more than one-third of ES-SCLC patients present brain metastases (BMs) at diagnosis. This study aimed to investigate the potential impact of TRT and cranial radiotherapy (CRT) for ES-SCLC patients with BMs.
Materials/Methods: ES-SCLC patients receiving first-line chemoimmunotherapy were enrolled from four medical centers during January 2020 to January 2024. The baseline characteristics, treatment strategies and survival data were collected. Kaplan–Meier curves using log-rank tests were performed to compare the overall survival (OS), progression-free survival (PFS), and intracranial PFS (iPFS) between different groups.
Results: A total of 343 ES-SCLC patients were included in this study, and 111 (32.4%) patients were found to have baseline BMs. In regard to treatment strategies for patients with BMs, 56 patients received additional TRT, while 37 patients received CRT. Survival analysis revealed no significant difference in outcomes between patients with baseline BMs and non-BMs subgroups. Among patients with BMs, the addition of TRT for ES-SCLC patients receiving chemoimmunotherapy was associated with significantly improved PFS (mPFS: 10.3 vs. 6.1 months, p<0.001) and OS (mOS: 22.1 vs. 17.5 months, p=0.037) compared to non-TRT subgroup. In terms of CRT, although no PFS benefit was observed with additional CRT, it has been found to markedly prolong iPFS (iPFS: 31.5 vs. 17.8 months, p=0.012) and OS (mOS: 23.3 vs. 20.1 months, p=0.037) compared to non-CRT group. Besides, the addition of both TRT and CRT was found a significantly enhanced survival benefit over only TRT or CRT or non-radiotherapy (mPFS: 11.8 vs. 9.8 vs.7.2 vs. 5.7 months, p<0.001; mOS: 31.0 vs. 21.7 vs. 21.4 vs.15.1 months, p=0.037).
Conclusion: The addition of TRT synergistically enhanced PFS and OS for ES-SCLC patients with baseline BMs receiving first-line chemoimmunotherapy. The integration of CRT and TRT may further amplifies survival benefits, thereby advocating for multimodal therapeutic strategies for ES-SCLC patients with baseline BMs.