Local Ablative Therapy Improves Survival in Patients with Synchronous Oligometastatic NSCLC Harboring EGFR Activating Mutation Treated with First-Line EGFR-TKIs

Abstract

The aim of the current study was to investigate whether consolidation local ablative therapy (LAT) can improve the survival of patients with stage IV EGFR-mutant NSCLC who have oligometastatic disease treated with first-line EGFR-TKI therapy. 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 radiation therapy 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 radiation therapy 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.