Abstract 14P
Background
The efficacy and safety of consolidative stereotactic body radiation therapy (SBRT) in patients with EGFR-mutant NSCLC who developed oligo-residual disease after first-line third-generation EGFR TKIs is unknown.
Methods
A single-arm, multicenter, phase II trial was conducted in patients with EGFR-mutant NSCLC who receiced SBRT for oligo-residual disease after first-line third-generation EGFR TKIs. The primary endpoint was progression-free survival (PFS), with secondary endpoints including overall survival (OS) and toxicity graded using CTCAE. A propensity score-matched comparison was also conducted with a contemporary cohort of patients who received EGFR TKIs alone.
Results
Sixty-four patients were enrolled in the trial. With a median follow-up of 18.2 (IQR, 13.6-26.4) months, the median PFS in all patients was 29.9 (95%CI, 21.0-38.8) months, with the lower boundary exceeding the predefined threshold. The median OS time had not been reached (95%CI, NA) and the 2-year OS rate was 88.8% (95%CI 70.3%-96.0%). In patients with cranial oligo-residual disease and receiving cranial SBRT, the median PFS was 27.0 (95%CI, 8.2-45.8) months. Adverse events (AE) were manageable, with pneumonitis and esophagitis being the most common toxicities. Four patients (6.3%) reported grade ≥3 AEs, each for pneumonitis, esophagitis, leukopenia and radiation necrosis. Propensity score-matched analysis showed significantly prolonged PFS in the SBRT+TKI group compared to the TKI alone group (HR 0.45, 95%CI 0.25-0.79; p =0.005).
Conclusions
Consolidative SBRT in patients with oligo-residual disease after first-line third-generation EGFR TKIs showed promising efficacy and acceptable toxicity profiles. This treatment approach may delay acquired resistance and improve survival outcomes. Further validation in larger prospective studies is warranted.
Clinical trial identification
NCT04764214.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.