2614 Background: This study seeks to elucidate the therapeutic benefits of integrating stereotactic radiotherapy (SRT) with immunotherapy for treating brain oligo-metastases (BMs) in patients with non-small cell lung cancer (NSCLC). Methods: In this retrospective real-world study, patients with driver-gene-negative NSCLC and 1-3 BMs were enrolled to evaluate the therapeutic benefits of combining SRT with immune checkpoint inhibitors (ICIs) and chemotherapy. The primary endpoint was overall survival (OS). Secondary endpoints included intracranial progression-free survival (iPFS), progression-free survival (PFS), and the response of intracranial lesions. Results: Based on chemotherapy (CT), 65 patients underwent SRT+ICIs therapy, 47 patients underwent SRT, and 44 patients underwent ICIs. For patients with with > 500 mm 3 BMs, SRT + ICIs + CT significantly improved the OS (22.1 vs. 13.5 vs. 18.5 months, p = 0.012), iPFS (17.5 vs. 7.8 vs. 11.8 months, p < 0.001), PFS (11.3 vs. 7.6 vs. 5.3 months, p = 0.019), and iORR (56.3% vs. 20.3% vs 28.9%, p = 0.001) compared to SRT+CT or ICIs + CT therapy. In the sub-group of patients of symptomatic BMs, SRT + ICIs + CT significantly improved the OS (24.7 vs. 14.7 vs. 17.5 months, p = 0.012), iPFS (13.7 vs. 9.8 vs. 11.8 months, p = 0.046), and iORR (34.5% vs. 13.8% vs 23.7%, p = 0.027) compared to SRT + CT or ICIs + CT therapy as well. Concurrent SRT with ICIs (time interval < 2 weeks) significantly improved the OS (28.2 vs. 15.4 months, p = 0.01), iPFS (25.8 vs. 12.1 months, p = 0.014), and iORR (63.2% vs. 37.0%, p = 0.017) when compared to sequential SRT with ICIs. Combined therapy did not increase the incidence of any grade of central nervous system and immune-related adverse events. Conclusions: Based on chemotherapy, the combination of concurrent SRT and ICIs improve the prognosis of driver-gene-negative NSCLC with BMs without increasing the occurrence of adverse events. Furthermore, it demonstrates increased effectiveness for treating larger and symptomatic intracranial lesions, specifically those > 500 mm 3 in volume. Data on patient outcomes. All Patients Sub-Group in Lesions > 500 mm 3 Sub-Group in Symptomatic Brain Metastases SRT+ICIs+CT Sub-Group Median, months SRT+ICIs+CT (n=65) SRT+CT (n=47) ICIs+CT (n=44) p-Value SRT+ICIs+CT (n=44) SRT+CT (n=28) ICIs+CT (n=17) p-Value SRT+ICIs+CT (n=38) SRT+CT (n=38) ICIs+CT (n=21) p-Value Concurrent (n=31) Sequential (n=34) p-Value OS 23.0 14.2 18.7 0.033 22.1 13.5 18.5 0.012 24.7 14.7 17.5 0.012 28.5 15.4 0.01 iPFS 15.3 8.5 13.0 0.002 17.5 7.8 11.8 < 0.001 13.7 9.8 11.8 0.046 25.8 12.1 0.014 PFS 9.8 6.7 8.0 0.072 11.3 7.6 5.3 0.019 8.9 6.7 5.7 0.13 12.2 9.0 0.009 iORR 48.8% 24.5% 49.0% 0.01 56.3% 20.3% 28.9% 0.001 34.5% 13.8% 23.7% 0.027 63.2% 37.0% 0.017 iDCR 83.3% 75.5% 76.5% 0.46 85.4% 62.1% 72.2% 0.063 22.2% 17.2% 12.7% 0.61 92.1% 76.1% 0.05 SRT, stereotactic radiotherapy; ICIs, immune checkpoint inhibitors; CT, chemotherapy; OS, overall survival; iPFS, intracranial progression free survival; PFS, progression free survival; iORR, intracranial overall response rate; iDCR, intracranial disease control rate.
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