Stereotactic body radiotherapy to the lung primary lesion improves the survival of patients with non-oligometastatic NSCLC harboring EGFR activating mutation with first-line EGFR-TKIs: A real-world study.

Abstract

e21131 Background: This study aimed to explore the clinical value of SBRT for lung primary lesions of EGFR-mutant NSCLC patients with non-oligometastatic disease during first-line EGFR-TKI treatment. Methods: Patients with stage IV EGFR-mutant NSCLC and more than five metastases at diagnosis were identified. All patients were treated with first-line EGFR-TKIs and SBRT for their primary lesions. The primary end points were the progression-free survival-1 (PFS1, time of first TKI dose relative to disease progression based on RECIST), and PFS2 (time of first TKI dose relative to disease progression after SBRT). The secondary endpoints were overall survival (OS) and safety. Results: 79 patients were enrolled, including 45 patients who received SBRT for their primary tumor at the maximal response of EGFR-TKI (the preemptive RT group) and 34 patients who received SBRT for their primary tumor after the occurrence of oligo-progression (the delayed RT group). The preemptive RT group had a significantly better median PFS1 than the delayed RT group (22.3 months vs. 12.9 months, P = 0.0031). The median PFS2 in the preemptive RT and delayed RT groups were 22.3 and 28.9 months, respectively (P = 0.17). The median OS did not differ significantly between the preemptive RT group and the delayed RT group (46.6 versus 51.3 months, P = 0.54). No severe toxicities (≥ grade 3) were recorded. Conclusions: This real-world study showed that preemptive RT to lung primary tumors is a feasible option for patients with EGFR-mutant non-oligometastatic NSCLC who had stable disease during first-line EGFR-TKI treatment, with significantly improved PFS and OS.