Abstract 1227P
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.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.