Extrapulmonary Small Cell Carcinoma: A Single-Institution Review of Brain Metastases, Treatment Paradigms, and...

Purpose Small cell carcinoma of the lung (SCLC) often presents with brain metastases, with most patients developing them within a few years of diagnosis. Prophylactic cranial irradiation (PCI) is commonly recommended. Extrapulmonary small cell carcinoma (EPSCC) is rare, and its metastatic pattern is not well understood. This study reviews brain metastases in EPSCC patients at a single institution, focusing on management and overall survival (OS). Materials We identified EPSCC patients and analyzed their characteristics, treatment, and outcomes. Brain metastases were assessed through diagnostic imaging. Extracranial progression-free survival (ePFS) was defined as the time from diagnosis to progression outside the brain, while OS was defined as the time from diagnosis to death from any cause. Kaplan-Meier methods and log-rank tests were used for time-to-event analyses, and the cumulative incidence of brain metastasis was estimated with the competing risk of death. Statistical significance was set at p < 0.05. Results Of the 68 EPSCC patients with a median follow-up of 7.1 months, 66% were male with a median age of 68 years old. Common primary sites included genitourinary (32%) and gastrointestinal/hepatobiliary (22%). Brain metastases occurred in 12 patients (18%): five at diagnosis and seven during follow-up. The treatment of brain metastases varied, with four patients receiving whole-brain radiotherapy (WBRT), two receiving stereotactic radiosurgery (SRS), and one receiving both WBRT and SRS. The median OS was 10.0 months, with no significant survival difference between patients with (10.8 months) and without (9.4 months) brain metastases (p = 0.89). Conclusion EPSCC has a lower incidence of brain metastases than SCLC, and brain metastases do not significantly impact OS. Further research on brain imaging, PCI, and management strategies is warranted.