MMAP-13 TREATMENT MODALITIES AND SURVIVAL OUTCOMES IN NEUROENDOCRINE LUNG CANCER PATIENTS WITH BRAIN METASTASES: A REAL-WORLD ANALYSIS OF THE NATIONAL CANCER DATABASE

Abstract Brain metastases (BM) are a frequent and severe complication in neuroendocrine lung cancer (LCNEC), but data on treatment patterns and survival outcomes are limited. We analyzed the National Cancer Database (2010–2021) enrolling LCNEC patients with BM. Descriptive statistics, Kaplan-Meier survival analysis, and multivariable Cox regression were performed. Of 285,358 lung cancer patients, 41,514 (14.5%) had LCNEC with BM. BM incidence increased from 131 per 1,000 in 2010 to 162 per 1,000 in 2021. Median age was 66 years (IQR: 59.0-72.0); 50.5% were male and 54.1% had Medicare. Common primary tumor sites were upper lobe (45.2%), lower lobe (20.2%), and bronchus (9.2%). Small cell histology accounted for 86.2% of cases. Treatment distributions were systemic therapy with whole-brain radiotherapy (Sys+WBRT, 34.8%), systemic therapy only (29.7%), systemic therapy with stereotactic radiosurgery (Sys+SRS, 6.7%), and no treatment (17.7%). Median overall survival (OS) was longest with Sys+SRS (10.3 months), followed by Sys+WBRT (8.7 months) and systemic therapy alone (7.8 months). SRS only (2.9 months), WBRT only (2.0 months), and no therapy (1.3 months) were associated with inferior outcomes. Compared to Sys+SRS, multivariable Cox regression showed higher mortality with Sys+WBRT (HR 1.22, 95% CI 1.16–1.27, p<0.001), Sys only (HR 1.32, 95% CI 1.27–1.38, p<0.001), SRS only (HR 2.18, 95% CI 1.99–2.38, p<0.001), WBRT only (HR 3.14, 95% CI 2.98–3.30, p<0.001), and no treatment (HR 4.00, 95% CI 3.81–4.19, p<0.001). Worse OS was also independently associated with age ≥60 (HR 1.41, p<0.001), Medicaid (HR 1.04, p=0.024), uninsured status (HR 1.21, p<0.001), low education (HR 1.09, p<0.001), and comorbidity score ≥2 (HR 1.22, p<0.001). Multimodal treatment, especially Sys+SRS, offered the most favorable survival in LCNEC patients with BM. Age ≥60 years, Medicaid, uninsured status, lower education, and comorbidity score ≥2 was associated with inferior survival.