3599 - Patterns of Failure in Synchronous Metastatic Non-Small Cell Lung Cancer without Driver Alterations According to Metastatic Burden
Presenter(s)
W. J. Rhee, S. Park, J. Chang, H. I. Yoon, J. Cho, and K. H. Kim; Department of Radiation Oncology, Yonsei Cancer Center, Heavy Ion Therapy Research Institute, Yonsei University College of Medicine, Seoul, Korea, Republic of (South)
Purpose/Objective(s): Patterns of failure (POF) after first-line immune checkpoint inhibitor (ICI)-based therapy in patients with synchronous metastatic non-small cell lung cancer (NSCLC) without oncogenic driver alterations may guide selection of candidates for local consolidative therapy (LCT).
Materials/Methods: We retrospectively evaluated patients diagnosed with synchronous metastatic NSCLC between January 2017 and December 2023. Patients with oncogenic driver alterations, or who did not receive ICIs as first-line therapy, or who lacked follow-up imaging were excluded. Patients were stratified into four groups according to the number of metastatic lesions: 1, 2, 3–5, and >5 lesions. POF were classified as original site recurrence (OSR) or new site recurrence with or without OSR (NSR). Competing risk analyses were performed.
Results: Altogether, 221 patients were analyzed, with a median follow-up of 28.1 months. Initial failure patterns did not differ significantly across lesion-number groups (p = .417). The 2-year cumulative incidence of OSR was not significantly different between the groups (p = .828). A trend toward a lower NSR was observed in patients with a single metastatic lesion (p = .063). Analysis of subsequent failures revealed a higher rate of NSR in the 1-lesion group compared with that in the other groups (p = .043). No independent predictors of OSR were identified in multivariate analysis.
Conclusion: In synchronous metastatic driver-negative NSCLC treated with first-line ICI-based therapy, both OSR and NSR were common and largely independent of the metastatic burden, suggesting that the lesion number alone may be insufficient for selecting candidates for LCT.