Real-World Survival of First-Line Immune Checkpoint Inhibitor Treatment Versus Chemotherapy in Older Patients With Non–Small-Cell Lung Cancer and Synchronous Brain Metastases

ABSTRACT

PURPOSE

This study assessed real-world survival among older patients with non–small-cell lung cancer (NSCLC) and brain metastases (BMs) at diagnosis (synchronous BM [SBM]) receiving first-line immune checkpoint inhibitors (ICIs) compared with chemotherapy only.

METHODS

Patients with NSCLC and SBM age 65 years or older at diagnosis from 2010 to 2019 SEER-Medicare database and received US Food and Drug Administration–approved ICIs (pembrolizumab/nivolumab/ipilimumab/atezolizumab/durvalumab/cemiplimab) and/or chemotherapy (platinum-based doublets/taxane/pemetrexed/gemcitabine) as first-line systemic treatment were included, excluding those with no cranial radiation or ever being treated with targeted therapies. Overall survival time was from the start of systemic treatment (ICI/chemotherapy) to death, censored at disenrollment from Medicare part A/B, enrollment in part C, or end of the study period (December 31, 2019). Kaplan-Meier (KM) survival curves were compared between treatment groups using the log-rank test. Multivariable Cox proportional hazards (CPH) model was used to estimate hazard ratio (HR) between groups, adjusting for patients’ sociodemographic and clinical characteristics.

RESULTS
The study included 1,481 patients (1,303 chemotherapy and 178 ICI). The median (range) age was 71 (65-91) years. First-line ICI patients were more likely to be older, live in urban areas, and less likely to be non-White than the chemotherapy group. KM estimates showed that survival curves initially overlapped but diverged approximately 6 months after initiating first-line systemic treatment (median survival [95% CI]: ICI, 190 [131 to 303] days versus chemotherapy, 189 [177 to 201] days), with ICI showing a better survival than the chemotherapy group (log-rank test P < .0001). First-line ICI was associated with a lower risk of death compared with chemotherapy in adjusted CPH model (HR [95% CI], 0.67 [0.55 to 0.80]; P < .0001).

CONCLUSION
Among older patients with NSCLC and SBM, first-line ICI use was associated with improved survival occurring 6 months after treatment initiation compared with chemotherapy only.

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