2362 - Role of Thoracic Radiotherapy in Extensive-Stage Small Cell Lung Cancer Patients with Bone Metastases: A Multicenter Retrospective Analysis
Presenter(s)
X. Fan1, B. Li1, C. Jiang2, J. Feng1, T. Dong3, 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 Otorhinolaryngology & Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China, 3Department of Obstetrics and Gynecology, Qilu Hospital of Shandong 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): The integration of chemotherapy and immunotherapy has revolutionized the first-line treatment paradigm for extensive-stage small-cell lung cancer (ES-SCLC), with emerging evidence suggesting that the addition of thoracic radiotherapy (TRT) further enhances survival outcomes. Notably, a majority of patients present with numerous bone metastases at initial diagnosis, and the role of TRT in ES-SCLC with bone metastases requires further exploration.
Materials/Methods: ES-SCLC patients receiving first-line chemoimmunotherapy were enrolled from four medical centers between January 2020 and January 2024. The baseline characteristics, treatment strategies, and survival data were systematically collected. Overall survival (OS) and progression-free survival (PFS) were analyzed using Kaplan–Meier method and compared with log-rank tests.
Results: 343 ES-SCLC patients receiving first-line chemotherapy and immunotherapy were included in this study, and 108 (31.5%) patients had baseline bone metastases. Of these patients, 49 received chemoimmunotherapy combined with TRT, while 23 received radiotherapy targeting bone metastases. Compared to patients without bone metastases, those with bone metastases were found to have significantly inferior PFS (mPFS: 7.4 vs. 9.0 months, p=0.005) and OS (mOS: 21.2 vs. 22.7 months, p=0.002). Among patients with baseline bone metastases, the addition of TRT has significantly prolong PFS (mPFS: 8.9 vs. 6.1 months, p<0.001) and OS (mOS: 21.8 vs. 20.3 months, p=0.033) compared to non-TRT subgroup. Although there was no PFS benefit from the radiotherapy targeting bone metastases (mPFS: 8.5 vs. 7.3 months, p=0.365), a trend toward prolonged OS was observed (mOS: 24.7 vs. 21.8 months, p=0.091). The combination of TRT and radiotherapy for bone metastases demonstrated extended PFS compared to TRT or radiotherapy for bone metastases alone or non-radiotherapy (P = 0.009).
Conclusion: TRT could synergistically enhance PFS and OS for ES-SCLC patients with baseline bone metastases receiving first-line chemoimmunotherapy. However, the additional benefit of incorporating radiotherapy for bone metastases into TRT necessitates further investigation to substantiate its impact on survival outcomes.