2490 - Primary Lesion-Directed Stereotactic Body Radiotherapy for Advanced Non-Small Cell Lung Cancer Treated with First-Line Systemic Therapy
Presenter(s)
D. Tao1, Z. Yuan1, L. Yang2, D. Yang3, Y. Jiang2, W. Zhou2, Y. Wang4, and Y. Wu3; 1Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, China, China, 2Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, China, 3Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, China, 4Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, China, Chongqing, China
Purpose/Objective(s): The primary lesion is the common site of recurrence and progression in patients with advanced non-small cell lung cancer (NSCLC) receiving systemic therapy. However, the role of primary lesion-directed therapy (PDT) in advanced NSCLC remains unclear. This study aimed to evaluate the efficacy and safety of the primary lesion-directed stereotactic body radiotherapy (SBRT) for advanced NSCLC treated with first-line systemic therapy.
Materials/Methods: We retrospectively identified patients with advanced NSCLC who were suitable to receive SBRT for the primary lung lesion after first-line systemic therapy between 2019 and 2024. All eligible patients received first-line systemic therapy and were treated with SBRT for their primary lung lesions before disease progression. SBRT was delivered to the primary lesion, with doses ranging from 48 to 60 Gy in 4-5 fractions (for peripheral lesions), or 60 to 70 Gy in 8-10 fractions (for central lesions). The progression-free survival (PFS) was defined as the time interval from the start of first-line systemic therapy to disease progression or death from any cause. Overall survival (OS) was defined as the time interval from the start of first-line systemic therapy to death. Clinical outcomes, including local control, PFS, OS, and treatment-related toxicity, were assessed.
Results: A total of 198 patients with advanced NSCLC treated with SBRT for lung tumors were screened, and 50 patients were eligible for enrollment in this study. The median age of this cohort of patients was 65 years (range, 35–84 years), 33 (66%) patients were male, and 27 (54%) were smokers. Twenty (40%) patients received chemotherapy and immunotherapy, and 30 patients (60%) received target therapy. The median follow-up time was 35.9 months. The 2- and 3-year local control rate was 88.2% and 83.8%, respectively. The median PFS was 34.3 months (95% confidence interval [CI], 23.2–45.4 months). The 2- and 3-year PFS rates were 69.7% and 49.4%, respectively. The median OS was not reached, while the 2- and 3-year OS rates were 88.0% and 85.2%, respectively. The treatment was well-tolerated, with grade 1-2 toxicities (e.g., pneumonitis, esophagitis) reported in 15 (30%) of patients. Severe adverse events (grade 3 or higher) were not observed in all patients.
Conclusion: Primary lesion-directed SBRT obviously improved PFS and OS with acceptable toxicity compared to historical controls and is a novel and promising therapeutic strategy for patients with advanced NSCLC who had stable disease after first-line systemic therapy.