Abstract 55P
Background
Our previous studies indicated potential survival benefit of upfront cranial stereotactic radiotherapy (ucSRT) in third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)-treated EGFR-mutant non-small cell lung cancer (NSCLC) with baseline limited brain metastases (BMs). However, the optimal timing and patient selection of ucSRT in this disease population remain controversial.
Methods
Consecutive EGFR-mutant NSCLC patients with baseline limited BMs receiving third-generation EGFR-TKIs alone (TKI alone) or in combination with ucSRT (TKI+ucSRT), were identified from a multicenter prospective database (NCT06613633). ucSRT performed within or after 4 weeks of the initiation of third-generation EGFR-TKIs were classified as concurrent or consolidative SRT, respectively. Overall survival (OS), progression-free survival (PFS), and intracranial PFS (iPFS) were extensively compared in propensity score matched (PSM) patient subgroups.
Results
Among the 400 patients included, 266 (66.5%), 82 (20.5%), and 52 (13.0%) were in the TKI alone, concurrent SRT and consolidative SRT group, respectively. Compared to those in the TKI alone group, concurrent and consolidative SRT were associated with improved iPFS and PFS, the latter of which was also associated with prolonged OS [31.1 vs not reached (NR) months, P=0.0026]. Moreover, patients in the TKI alone group were further divided into two subgroups, with (n=71) or without (n=189) intracranial complete response (iCR). Compared to those in the iCR subgroup, neither concurrent SRT nor consolidative SRT was associated with improved OS. Nevertheless, compared to those in the non-iCR subgroup, consolidative SRT, but not concurrent SRT, was associated with prolonged OS.
Conclusions
Upfront cranial SRT, especially consolidative SRT, was associated with improved prognosis in third-generation EGFR-TKItreated NSCLC patients with baseline limited BMs. Those without intracranial complete response from EGFR-TKI monotherapy seemed to derive the most survival benefit from cranial SRT. Future validations are warranted.
Legal entity responsible for the study
Z. Zhu.
Funding
Key Clinical Specialty Project of Shanghai; National Science Foundation of China (No. 82172825).
Disclosure
All authors have declared no conflicts of interest.