MMOD-13 PREVALENCE, TREATMENT PATTERNS, AND SURVIVAL OUTCOMES OF PATIENTS WITH BRAIN METASTASES FROM SMALL CELL LUNG CANCER: A RETROSPECTIVE COHORT STUDY FROM 2013-2023 USING THE TRINETX ONCOLOGY DATABASE Open Access

Brain metastases (BM) portend increased morbidity and mortality in patients with small cell lung cancer (SCLC), yet nationwide reporting of BM is lacking. We aimed to characterize the prevalence, timing, treatment patterns, and survival outcomes of BM associated with SCLC over the past decade. Data from 4,014 patients with histologically confirmed SCLC were extracted from the TrinetX Oncology database. Clinical and demographic variables were compared between patients with and without BM using and Chi-squared and t-tests. Kaplan-Meier and Cox regression analyses were used to evaluate overall survival (OS), after propensity score matching cohorts for age at diagnosis of lung/bronchus cancer, sex, cancer stage at diagnosis, extracranial metastases, and cancer-directed therapy. Among 4,014 patients with SCLC, 34.98% had BM (9.89% synchronous, 21.18% metachronous, 3.91% precocious) At SCLC diagnosis, 0.75% had stage 0, 5.78% stage 1, 3.69% had stage 2, 20.35% had stage 3 cancer, and 48.75% had stage 4 cancer. Patients who developed BM were younger (p<0.001) at diagnosis of SCLC, more likely Black/African American (p= 0.0068), and presented with more advanced cancer stages (p<0.001) than patients who did not develop BM. The median BM-free survival from the time of SCLC diagnoses was 27.9 months. Patients with BM received significantly higher rates of cancer-directed therapies compared to those without BM. Synchronous BM were associated with lower OS than metachronous BM after the diagnosis of SCLC (HR[95%CI] = 1.56[1.32-1.83]), but there was no difference in OS after the BM diagnosis. OS did not differ significantly between patients with BM and patients with extracranial metastases only, following the diagnosis of BM or extracranial metastases, respectively. Our findings underscore the ongoing challenges in treating SCLC patients with BM and support routine intracranial screening as well as the development of interventions to prevent the development of BM in this population.