Stereotactic radiosurgery for brain metastases from newly diagnosed small cell lung cancer: practice patterns and outcomes

Background: Up-front stereotactic radiosurgery (SRS) has been historically thought of as inadequate for brain metastases (BM) from newly diagnosed small cell lung cancer (SCLC). This study evaluates national practice patterns and clinical outcomes for BM from SCLC. Material and methods: The National Cancer Database was queried (2004-2013) for patients with newly diagnosed metastatic SCLC receiving intracranial radiotherapy. Patients were grouped into three categories: upfront SRS, whole-brain radiotherapy (WBRT) alone, or WBRT with boost (SRS or fractionated radiotherapy). Statistics included temporal trend assessment by annual percent change (APC), logistic regression, exploratory Kaplan-Meier overall survival (OS) analysis without and with propensity matching, and Cox proportional hazards modeling. Results: A total of 14,722 patients met selection criteria, of whom 487 (3.3%), 13,657 (92.8%), and 578 (3.9%) received upfront SRS, WBRT and WBRT with boost, respectively. Utilization of SRS showed a slight increasing trend from 2004 to 2013 (2.7-4.3%). In addition to socioeconomic factors, other variables associated with SRS use included diagnosis after 2010, treatment at academic centers, and residing in higher-educated regions. SRS was less often delivered to patients with node-positive disease (p < .05). On exploratory analysis, SRS cohort was observed to have a higher overall survival (OS) than WBRT-based groups (p < .001), namely in patients without extracranial metastases. Conclusions: Utilization of up-front SRS for SCLC BM has been increasing over time but is driven by socioeconomic disparities. Although there are likely numerous biases associated with the OS findings herein, further research is needed to validate this finding as well as the role of SRS on patients with brain metastases due to SCLC.