OA07.05 Local Ablative Therapy Improves Survival in Patients with Synchronous Oligometastatic NSCLC Harboring EGFR Mutation Treated with EGFR-TKIs

Non-small-cell lung cancer (NSCLC) is the most common cause of cancer deaths worldwide. Patients with oligometastatic disease can represent an indolent phenotype that could benefit from local ablative therapy(LAT). Howerver, whether first-line continual EGFR-TKIplus LAT could have potential benefit in EGFR-mutant NSCLC patients with oligometastatic disease remains undetermined. Patients with stage IV EGFR-mutant NSCLC and no more than five metastases at diagnosis in 2 months were enrolled. All patients were treated with first-line EGFR-TKIs. Consolidation LAT included radiotherapy or surgery. Overall survival (OS) and progression-free survival (PFS) were estimated by Kaplan-Meier curves. From October 2010 to May 2016, 145 patients were enrolled, including 51 (35.2%) who received consolidation LAT to all oligometastatic sites (All-LAT group), 55 (37.9%) who received consolidation LAT to either primary tumor or oligometastatic sites (Part-LAT group), and 39 (26.9%) who did not receive any consolidation LAT (Non-LAT group). The median PFS in All-LAT, Part-LAT, and None-LAT group were 20.6 months, 15.6 months, and 13.9 months, respectively (P<0.001). The median OS in All-LAT, Part-LAT, and None-LAT group were 40.9 months, 34.1 months, and 30.8 months, respectively (P<0.001). The difference was significant between All-LAT group and Part-LAT or Non-LAT group but was not significant between Part-LAT and Non-LAT group. The median OS was significantly improved with consolidation LAT for primary tumor (40.5 versus 31.5 months, P<0.001), brain metastases (38.2 versus 29.2 months, P=0.002), adrenal metastases (37.1 versus 29.2 months, P =0.032). Adverse events (Grade≥3) due to radiotherapy included pneumonitis (7.7%) and esophagitis (16.9%). The current study demonstrated that consolidation LAT to all sites was a feasible option among patients with EGFR-mutant oligometastatic NSCLC during first-line EGFR-TKI treatment, with significantly improved PFS and OS compared with consolidation LAT to partial sites or observation alone.