Main Session
Sep
29
PQA 07 - Head and Neck Cancer, Lung Cancer/Thoracic Malignancies, and Nursing and Supportive Care
3526 - Survival Outcomes of Radiotherapy in Extensive-Stage Small-Cell Lung Cancer with Extracranial Oligoprogression after First-Line Therapy: A Multicenter Propensity Score-Matched Cohort Study
Presenter(s)
Jiatong Li, - Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong Province,
J. Li1,2, S. Lu1, X. Zhai1, J. Yu3, and H. Zhu1; 1Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Science, Jinan, China, 2Harbin Medical University, Harbin, Heilongjiang Province, China, 3Shandong Provincial Key Laboratory of Precision Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
Purpose/Objective(s):
Chemotherapy combined with immunotherapy remains the first-line standard treatment for extensive-stage small-cell lung cancer (ES-SCLC). However, almost all patients ultimately develop progression, and their prognosis varies significantly depending on the pattern of progression. The role and impact of radiotherapy in ES-SCLC are not well established. Therefore, this study aims to explore the efficacy of radiotherapy for patients with ES-SCLC who developed extracranial oligoprogression after first-line therapy.Materials/Methods:
Patients with ES-SCLC who received first-line chemotherapy or chemoimmunotherapy and subsequently developed extracranial oligoprogression were enrolled from three cancer centers (Shandong Cancer Hospital, Shanghai Chest Hospital, and Tianjin Cancer Hospital) between January 2020 and March 2025. All enrolled patients were categorized into the radiotherapy (RT) group and the non-RT group according to whether they received radiotherapy after first-line treatment progression. Propensity score matching (PSM) was used to balance baseline characteristics. Primary endpoints were second-line overall survival (OS2) and progression-free survival (PFS2), estimated by the Kaplan–Meier method and compared with the log-rank test (p < 0.05).Results:
By March 10, 2025, a total of 232 patients had developed extracranial oligoprogression following first-line treatment, with a median time to progression of 6.1 months (range: 1.0–37.8 months). Survival analysis results showed that PFS2 (before PSM: 7.3 vs. 3.6 months, p = 0.015; after PSM: 6.1 vs. 3.3 months, p = 0.007) and OS2 (before PSM: 13.4 vs. 8.9 months, p = 0.026; after PSM: 13.4 vs. 8.4 months, p = 0.029) were significantly prolonged in the RT group compared to the non-RT group. These benefits were more pronounced in certain subgroups, including the immunotherapy subgroup, the existing lesion progression subgroup, the intrathoracic progression subgroup, and the PFS1 > 6 months (delayed-progression) subgroup. Among matched patients (53 patients in the RT group; 53 patients in the non-RT group), the RT group demonstrated the most significant OS2 benefit in the intrathoracic progression subgroup (median OS2: 21.6 vs. 7.9 months; HR 0.63; p = 0.019), whereas the greatest improvement in PFS2 was observed in the delayed-progression subgroup (median PFS2: 9.6 vs. 4.4 months; HR 0.63; p = 0.009). Furthermore, regarding the second-line combined systemic treatment strategies in the RT group, patients who received continuous systemic therapy had significantly superior PFS2 (9.6 vs. 5.4 months, HR 0.48, 95% CI 0.26–0.89; p = 0.017) and OS2 (14.4 vs. 13.4 months, HR 0.47, 95% CI 0.24–0.94; p = 0.030) compared to those who received alternative systemic therapy.Conclusion:
This multicenter study confirmed that radiotherapy improved survival in ES-SCLC patients with extracranial oligo-progression. Among patients receiving RT, continuing first-line systemic therapy yielded greater clinical benefit.