Adenosquamous Carcinoma of the Esophagus: An NCDB-Based Investigation on Comparative Features and Overall Survival in a Rare Tumor

Objectives: Esophageal adenosquamous carcinoma (ASC) is a rare tumor with characteristics of adenocarcinoma (AC) and squamous cell carcinoma (SCC), the two most common esophageal cancers. Its behavior is aggressive but poorly understood. Using the National Cancer Database (NCDB), the clinical features and overall survival of ASC were compared with AC and SCC. Methods: The NCDB was queried for patients with esophageal ASC, AC, and SCC. Univariate association of histology with patient characteristics and overall survival were analyzed and socioeconomic characteristics were balanced. Results: Clinical M stage was 0 in a significantly lower proportion of ASC (69.0%) than in AC (70.9%) or SCC (75.6%) (p < 0.001). Median survival was lower in patients with ASC (9.6 months) than with AC (13.5) or SCC (9.7) and 2-year OS was lower in patients with ASC (23.8%) than with AC (34.6%) or SCC (26.5%) (p < 0.001). The OS hazard ratio for ASC was 1.14 when compared to AC (95% CI = 1.016-1.267, p = 0.025) and 1.10 when compared to SCC, but the latter was not significant (95% CI = 0.980-1.222, p = 0.111). Conclusion: ASC is a rare tumor among esophageal carcinomas with a greater burden of metastatic disease than AC or SCC and worse OS than AC.