Upfront Stereotactic Radiosurgery In The Treatment Of Brain Metastasis From Small Cell Lung Cancer

Patients with small cell lung cancer (SCLC) are at high risk of developing brain metastasis (BM). Despite high adoption of stereotactic radiosurgery (SRS) for BM of most histologies, SCLC patients with BM are typically treated with upfront whole brain radiotherapy (WBRT) based on the assumption of subclinical intracranial disease. We report the outcomes of patients with SCLC BM who were treated with upfront SRS. The records of patients at a single institution treated with SRS for SCLC BM without a history of brain radiation were reviewed. All patients had frequent brain MRI surveillance. Neurologic death was based on the EORTC definition of intracranial failure as a component of cause of death. Overall survival (OS), intracranial progression-free survival (PFS), freedom from neurologic death, and freedom from salvage radiotherapy were determined. Twenty patients treated in 2012-2018 fit the inclusion criteria. Median follow-up was 11.5 months, with 5 patients alive at last follow-up. Eighteen patients had extensive-stage SCLC at diagnosis and two developed BM after initial diagnosis of limited-stage SCLC. Fourteen patients received systemic therapy before SRS and six received SRS before any systemic therapy. Median number of BM at time of SRS was 2 (IQR 1 – 3.5) and median BM volume was 2.97cc (IQR 0.73 – 7.54). No progression was observed in 70 of 73 lesions treated (Local control 95.9%). Median OS from SRS was 6.7 months for all patients and 8.4 months for patients receiving any systemic therapy after SRS. Eleven patients had MRI evidence of CNS disease progression, with median intracranial PFS of 6.0 months and median freedom from salvage radiotherapy of 7.7 months. All four patients receiving salvage WBRT died within two months of salvage therapy. Four patients received salvage SRS, with two alive > 8 months after salvage and two deceased > 9 months after salvage. Four of 15 (27%) deceased patients died from neurologic causes. Freedom from neurologic death was 86.5% at 6 months and 69.2% at 12 months. 80% of patients with SCLC BM who received upfront SRS avoided WBRT, due to adequate intracranial control or competing risk from non-neurologic death. Although SRS in the upfront treatment of BM from SCLC needs further study, it may be an option in highly selected patients. Future study will compare this cohort with patients receiving WBRT matched by BM number/volume and performance status.Abstract 2182; Table 1Cohort CharacteristicsMean Age (years)68 (IQR 60-76)KPS80-10015<805Stage at DiagnosisLimited Stage2Extensive Stage18Body RadiationNone11Definitive2Palliative7Brain Metastasis at DiagnosisYes8No12Median Number of treated BM2 (IQR 1-3.5)Systemic Therapy before SRSNone6Chemotherapy11Chemoimmunotherapy3Systemic Therapy after SRSNone3Chemotherapy7Chemoimmunotherapy8Immunotherapy alone2Salvage WBRTYes4No16Salvage SRSYes4No16 Open table in a new tab