Presentation, treatment, and prognosis of colorectal adenosquamous carcinoma: A contemporary analysis of the surveillance, epidemiology, and end results database

Introduction: Colorectal adenosquamous carcinoma (ASC) represents <0.1% of colorectal cancers. Due to its rarity, there is paucity of data regarding its prognosis and treatment compared to other colorectal cancers. The aim of the study was to evaluate presentation, treatment and prognosis of colorectal ASC in comparison to adenocarcinoma (AC) and squamous cell carcinoma (SCC). Methods: Adult patients diagnosed with colorectal AC, SCC, and ASC between 2000 and 2017 were identified using Surveillance, Epidemiology, and End Results database. Results: Among the 446,132 patients diagnosed with colorectal cancer, 0.06% had ASC and were more likely to present with higher T stage and distant metastases compared to AC and SCC (p < 0.001). Major surgery was the primary treatment for colonic ASC, while for rectal ASC, chemotherapy and/or radiation were mainly utilized. Localized and distant colonic ASC had an unadjusted 5-year cause-specific survival that was worse than AC, while rectal ASC had the worst survival across all stages. Conclusion: Colorectal ASC usually present with advanced stage and have overall worse prognosis. Standardization of treatment strategies may improve survival in colorectal ASC.