Objective To explore the effectiveness of systemic therapy combined with local therapy for advanced patients with oligometastasis non-small cell lung cancer (NSCLC), and to analyze the factors associated with the prognosis of the patients.

Methods Retrospective analysis of 149 patients with advanced NSCLC oligometastasis admitted to Tian You Hospital of Wuhan University of Science and Technology from February 2018 to December 2021. Oligometastasis was defined as ≤3 metastatic organs and ≤5 metastatic lesions. Divide the enrolled patients into a study group (group A) and a control group (group B) based on whether to combine local treatment with stable primary lesions after systematic treatment.Patients in group A received systemic therapy in combination with local treatment, which included stereotactic radiotherapy(SBRT) and intensity-modulated conformal radiotherapy (IMRT). Forty-seven patients received SBRT at a prescribed dose of 48-52 Gy for 4-5 fractions.Forty-two patients received a dose of 60-65 Gy for 25-30 fractions.Sixty patients in group B received systemic therapy.Systemic therapy included chemotherapy, targeted therapy, immune checkpoint inhibitors (ICIs), and anti-angiogenesis.The primary endpoint of the study was progression-free survival (PFS) and the secondary endpoint was overall survival (OS). Survival analysis and survival curve plots were performed using the Kaplan-Meier method for PFS and OS in both groups, the Log-rank test to compare the difference in survival between groups, the Kaplan-Meier method and Cox regression for univariate and multifactorial analysis of PFS and OS.

Results The median follow-up time was 20.0 (12.0, 32.0) months in 149 patients. PFS was 14.7 (12.3, 16.7) months and 6.5 (4.0, 6.7) months in group A and B patients, respectively (HR=7.69, 95%CI 5.00-11.11). The OS of patients in group A and group B was 28.4 (18.0, 36.5) months and 16.1 (11.3, 24.7) months, respectively (HR=1.78, 95%CI 1.19-2.63). In subgroup analysis, patients in the SBRT and IMRT groups had a PFS of 16.7 (14.0, 18.3) months and 13.7 (12.0, 14.5) months (HR=2.43, 95%CI 1.54-3.84) and OS of 28.0 (19.3, 36.8) and 25.4 (10.3, 43.1) months (HR=2.04, 95%CI 1.22-3.33), respectively. Multifactorial analysis of intracranial metastases was a risk factor for PFS. Oligometastatic subgroup, brain metastatic subgroup, tissue type, ICIs, driver genes, anti-angiogenesis and local treatment modality were influential factors affecting OS.

Conclusions In patients with stable oligometastases in advanced NSCLC, local radiotherapy combined with systemic therapy significantly improves PFS and OS compared with systemic therapy alone, and SBRT is significantly better than IMRT.Intracranial metastasis is a poor prognostic factor.