2090 - A Single Arm Phase II Study Assessing Efficacy of Stereotactic Radiosurgery (SRS) for Brain Metastasis (BM) from Small Cell Lung Cancer (SCLC)

Purpose/Objective(s): Brain metastases (BM) are common in SCLC, with more than 50% developing BM during their disease course. Traditionally, patients with SCLC BM have been treated with whole brain radiation therapy (WBRT) and patients with extensive stage SCLC without BM received prophylactic cranial irradiation (PCI). However, WBRT has significant negative effects on neurocognition and quality of life, and recent studies failed to demonstrate a benefit of PCI in the era of modern surveillance magnetic resonance imaging (MRI). SRS is an established treatment for BM with comparable survival to WBRT, and SCLC patients followed with surveillance MRI who develop new BM can be salvaged with subsequent SRS. For SCLC patients with BM, a recent phase II single-arm clinical trial demonstrated promising outcomes with SRS, and the ongoing NRG-CC009 phase III randomized controlled trial will compare outcomes between WBRT and SRS. These studies are limited by the inclusion of up to 10 BM, and neither study included biomarker analysis. The proposed study will evaluate SRS for SCLC patients with up to 20 BM, the current standard-of-care for non-SCLC histologies, and integrate blood and cerebrospinal fluid (CSF) biomarkers, particularly circulating tumor DNA (ctDNA) profiling, to identify biomarkers of CNS failure to guide SRS as a management strategy in SCLC patients with BM.

Materials/Methods: This is a single arm phase II trial evaluating SRS as an effective treatment in patients with SCLC brain metastases. Eligible patients are adults (=18 years) with up to 20 SCLC brain metastases on contrast-enhanced brain MRI with good performance status (ECOG 0-2, KPS 60-100). Key exclusion criteria include evidence of leptomeningeal disease (LMD) on MRI or cytology, prior brain-directed radiotherapy, and uncontrolled systemic disease without reasonable systemic therapy options.