Primary adenosquamous carcinoma of the esophagus

AIM: To investigate the clinical characteristics, diagnosis, treatment, and prognosis of primary adenosquamous carcinoma (ASC) of the esophagus.METHODS: A total of 4015 patients with esophageal carcinoma underwent surgical resection between January 1995 and June 2012 at the Cancer Hospital of Shantou University Medical College. In 37 cases, the histological diagnosis was primary ASC. Clinical data were retrospectively analyzed from these 37 patients, who underwent transthoracic esophagectomy with lymphadenectomy. The χ² or Fisher’s exact test was used to compare the clinicopathological features between patients with ASC and those with squamous cell carcinoma (SCC). The Kaplan-Meier and Log-Rank methods were used to estimate and compare survival rates. A Cox proportional hazard regression model was used to identify independent prognostic factors.RESULTS: Primary esophageal ASC accounted for 0.92% of all primary esophageal carcinoma cases (37/4015). The clinical manifestations were identical to those of other types of esophageal cancer. All of the 24 patients who underwent preoperative endoscopic biopsy were misdiagnosed with SCC. The median survival time (MST) was 21.0 mo (95%CI: 12.6-29.4), and the 1-, 3-, and 5-year overall survival rates were 67.5%, 29.4%, and 22.9%, respectively. In multivariate analysis, only adjuvant radiotherapy (HR = 0.317, 95%CI: 0.114-0.885, P = 0.028) was found to be an independent prognostic factor. The MST for ASC patients was significantly lower than that for SCC patients [21.0 mo (95%CI: 12.6-29.4) vs 46.0 mo (95%CI: 40.8-51.2), P = 0.001]. In subgroup analyses, the MST for ASC patients was similar to that for poorly differentiated SCC patients.CONCLUSION: Primary esophageal ASC is a rare disease that is prone to be misdiagnosed by endoscopic biopsy. The prognosis is poorer than esophageal SCC but similar to that for poorly differentiated SCC patients.