ESTRO 2024 - Abstract Book

S1813

Clinical - Lung

ESTRO 2024

The purpose of this work was to explore the clinical characteristics and oncological outcomes of patients with intracranial-only (i.e. brain metastases), extracranial-only and mixed-pattern oligometastatic disease (OMD) from non-small cell lung cancer (NSCLC) that were treated with metastasis-directed stereotactic body radiotherapy. This study also aimed to investigate the correlation of clinical covariates with these oncological outcomes.

Material/Methods:

In this retrospective single-center cohort study, the data of 763 patients collected in two separate institutional databases from the Department of Radiation Oncology of the University Hospital of Zurich was screened. The OMD status was defined according to the ESTRO EORTC classification (1). The overall survival (OS) and progression-free survival (PFS) times were estimated using the Kaplan Meier method and compared with pairwise log-rank tests. Univariable and multivariable Cox regression models were used to determine the impact of various clinical characteristics on survival outcomes.

Results:

In total, 193 patients with a median age of 65.5 years were included: 58 patients in the intracranial cohort, 61 patients in the mixed-pattern cohort, and 74 patients in the extracranial cohort. Across all cohorts, the type of systemic therapy before or at OMD diagnosis was chemotherapy for 108 patients, targeted therapy for 19 patients, and immunotherapy for 9 patients. The other 57 patients did not receive systemic therapy. In the entire cohort, 20 patients had an EGFR mutation, 8 patients had an ALK mutation and 1 patient had a ROS mutation.

Figure 1: Kaplan-Meier estimate of OS by cohort.

Figure 2: Kaplan-Meier estimate of PFS by cohort.

The median OS and PFS were significantly lower in the mixed-pattern cohort (OS = 14.1 months [95% CI: 8.5 – 40.7]; PFS = 2.1 months [95% CI: 1.7 – 2.9]) than in the extracranial cohort (OS = 35.9 [95% CI: 26.9 – not reached]; PFS = 4.5 months [95% CI: 3.0 – 10.2]) and intracranial cohort (OS = 35.2 months [95% CI: 21.3 – not reached]; PFS = 5.0 months [95% CI: 3.6 – 7.8]).