125I brachytherapy as consolidative local therapy for patients with synchonous oligometastatic non-small cell lung cancer without progression after first-line chemotherapy plus PD-1 inhibitors treatment：A retrospective observational study

Abstract

Purpose The aim was to investigate the safety and efficacy of 125I brachytherapy as consolidative local therapy for patients with synchonous oligometastatic non-small cell lung cancer (sOM-NSCLC) without progression after first-line chemotherapy plus PD-1 inhibitors treatment consolidative percutaneous. Materials and Methods We retrospective analyzed 38 patients (31 male [81.6%], 7 women [18.4%], median age 66 years,range:[47-77 years] ) with sOM-NSCLC without epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) genetic aberrations, who were treated with first-line chemotherapy plus PD-1inhibitors 4-6 cycles followed by consolidative CT-guided 125I brachytherapy and maintenance therapy with PD-1 inhibitors in our hospital between June 2020 to June 2022 . Treatment efficacy and adverse events were evaluated. Results At the cutoff date of December 2022, the median follow-up time was 16.5 months (range: 7-28 months). 26 patients had progressive disease (PD) and 6 patients had died, the median progression free survival (mPFS) was 17.0 months (95% CI, 12.0-22.0 months). 1 patient had complete response (CR), 26 patients had partial response (PR), 10 patients had stable disease (SD), 1 patient had progressive disease (PD). The best objective response rate (ORR) was 71.1%. Patients with PD-L1 positive cancers and 1-3 metastatic lesions had longer PFS than patients with PD-L1 negative and 4-5 metastatic lesions (18.0 months vs 12 months, p=0.038) and (17.0 months vs 9 months, p=0.010 ). The lymph node stage was an independent prognostic factor for PFS (19 months vs 9 months, p=0.002). Conclusion 125I brachytherapy is a safe, feasible and valuable consolidative treatment for consideration in patients with sOM-NSCLC after first line chemotherapy plus PD-1 inhibitors treatment.