Abstract 14P
Background
Our previous studies indicated potential survival benefit of consolidative stereotactic radiotherapy (SRT) in metastatic driver mutation-negative non-small cell lung cancer (NSCLC) patients harboring oligo-residual disease (ORD) after effective immune checkpoint inhibitor (ICI) treatment. However, prospective data about consolidative SRT in this disease population after first-line chemoimmunotherapy remains scarce.
Methods
Metastatic driver mutation-negative NSCLC patients harboring ORD after effective first-line chemoimmunotherapy were enrolled in this single-arm, phase II trial (Trial registration number: NCT04767009). Extracranial and/or cranial SRT was performed covering all of the oligo-residual lesions, and the maintenance systemic therapy was not held during SRT. The primary endpoint was progression-free survival (PFS) and a sample size of 59 patients was calculated (median PFS, H0=10.0 months, HR=0.60, α=0.05 (onesided), β=0.10, dropout rate=10%). Secondary endpoints included overall survival (OS) and treatment-related adverse events (TRAEs). A prespecified propensity score-matched (PSM) comparison was conducted with a contemporary cohort of patients who developed ORD but received systematic therapy alone.
Results
From March 2021 to March 2023, 59 patients were enrolled and treated. The most common sites targeted by consolidative SRT included the lung (n=30), lymph nodes (n=26), bone (n=22), and brain (n=22). With a median follow-up of 14.8 months, the median PFS was 29.0 (90% CI 13.97-Not Reach) months, meeting the primary endpoint. The median OS was not reached and the 2-year OS rate was 88.9% (90% CI 77.9%-100%). TRAEs of any grade and grade ≥ 3 occurred in 58 (98.31%) and 13 (22.03%) patients, respectively. Incorporating consolidative SRT was associated with prolonged PFS (adjusted HR 0.286, P < 0.001) and OS (adjusted HR 0.229, P=0.023) after PSM analyses.
Conclusions
Consolidative SRT is associated with an encouraging PFS and generally acceptable toxicities in first-line chemoimmunotherapytreated metastatic NSCLC patients harboring ORD. Confirmatory studies are warranted.
Clinical trial identification
NCT04767009, Release date: 2021-02-19.
Legal entity responsible for the study
Z. Zhu.
Funding
Key Clinical Specialty Project of Shanghai and the Chinese Society of Clinical Oncology Foundation (No. Y-BMS2019-082).
Disclosure
All authors have declared no conflicts of interest.