Outcomes of rare histologic variants of esophageal cancer: A National Cancer Database analysis.

299 Background: Esophageal cancer is most often adenocarcinoma or squamous cell carcinoma, while rare histologies such as basaloid squamous carcinoma, sarcomatoid carcinoma, and neuroendocrine carcinoma (NEC) are poorly characterized. We aimed to evaluate incidence, treatment strategies, and survival outcomes of these unusual variants using a national cohort. Methods: We queried the National Cancer Database (2004–2019) for patients with esophageal cancer identified by ICD-O-3 morphology codes: basaloid squamous carcinoma (8083/3), sarcomatoid carcinoma (8033/3), and NEC (8013/3, 8246/3). Outcomes were compared with conventional squamous cell carcinoma (SCC) and adenocarcinoma (AC). Kaplan–Meier and multivariable Cox regression were used to estimate overall survival (OS). Results: Among 195,612 esophageal cancer cases, 682 (0.35%) were rare histologies: 231 basaloid SCC, 147 sarcomatoid carcinoma, and 304 NEC. Median age was 63 years, and 71% were male. Compared with SCC and AC, patients with rare histologies were more frequently diagnosed with advanced disease (56% vs 44%, p