Consolidative Local Ablative Therapy Improves the Survival of Patients With Synchronous Oligometastatic NSCLC Harboring EGFR Activating Mutation Treated With First-Line EGFR-TKIs

Abstract

Introduction: The aim of the current study was to investigate whether consolidative 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-tyrosine kinase inhibitor (TKI) therapy.

Methods: Patients with stage IV EGFR-mutant NSCLC and no more than five metastases within 2 months of diagnosis were identified. All patients were treated with first-line EGFR-TKIs. Consolidative LAT included radiotherapy, surgery, or both. Overall survival (OS) and progression-free survival (PFS) were estimated by Kaplan-Meier curves.

Results: From October 2010 to May 2016, 145 patients were enrolled, including 51 (35.2%) who received consolidative LAT to all oligometastatic sites (all-LAT group), 55 (37.9%) who received consolidative LAT to either primary tumor or oligometastatic sites (part-LAT group), and 39 (26.9%) who did not receive any consolidative LAT (non-LAT group). The median PFS in all-LAT, part-LAT, and non-LAT groups were 20.6, 15.6, and 13.9 months, respectively (p < 0.001). The median OS in all-LAT, part-LAT, and non-LAT groups were 40.9, 34.1, and 30.8 months, respectively (p < 0.001). The difference was statistically significant between the all-LAT group and part-LAT or non-LAT group but was not between the part-LAT and non-LAT group. The median OS was significantly improved with consolidative LAT for primary tumor (40.5 versus 31.5 months, p < 0.001), brain metastases (38.2 versus 29.2 months, p = 0.002), and 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%).

Conclusions: The current study showed that consolidative LAT to all metastatic sites was a feasible option for patients with EGFR-mutant oligometastatic NSCLC during first-line EGFR-TKI treatment, with significantly improved PFS and OS compared with consolidative LAT to partial sites or observation alone.

Keywords: Consolidation; EGFR–tyrosine kinase inhibitor; Local ablative therapy; NSCLC; Oligometastases.