Prognostic Factors and Survival in Gastrointestinal Extrapulmonary Small Cell Carcinoma: A Retrospective Cohort Study

Gastrointestinal extrapulmonary small cell carcinoma (GI EPSCCa) is a rare, aggressive neuroendocrine tumor. Factors affecting survival, including the prognostic significance of primary tumor site, remain under investigation.

Data from the surveillance, epidemiology, and end results (SEER) program were extracted to identify patients diagnosed with GI EPSCCa between 2000 and 2018. Cox proportional hazard models were used to assess prognostic factors based on primary tumor site.

A total of 1687 patients were included in the survival analysis. The distribution of the primary tumor location was as follows: 31.5% colorectum (CRC), 22.1% esophageal, 20.6% pancreatic, 13.3% hepatobiliary (HB), 10.6% stomach, and 1.8% small intestine (SI). Esophagogastric and SI EPSCCa were more common among Black individuals, whereas CRC, HB, and pancreatic EPSCCa were more common among White patients (p = 0.012). There were no racial differences in OS for GI EPSCCa. HB EPSCCa was associated with inferior OS compared with esophageal tumors (adjusted hazard ratio [aHR] 1.21, 95% confidence interval [CI] 1.00-1.46; p = 0.048), and SI EPSCCa was associated with prolonged survival compared with esophageal EPSCCa (aHR 0.76, 95% CI 0.48-1.20; p = 0.237) but did not reach statistical significance. Surgical intervention and a treatment period after 2006 were associated with superior OS.

The prognosis for GI ESPCCa varies based on site. Chemotherapy, radiation, and surgical resection are associated with improved outcomes; however, the prognosis for patients with EPSCCa remains dismal. Prospective studies are needed to guide therapy for this aggressive tumor.