Clinical Significance of the Duplicated Muscularis Mucosae in Barrett Esophagus-related Superficial Adenocarcinoma

Objective: The purpose of this study was to evaluate the relationship between the depth of invasion within the mucosal compartment, with particular attention to the duplicated muscularis mucosae, and survival after esophagectomy performed as treatment for Barrett esophagus-related superficial adenocarcinoma. Methods: A total of 185 patients with pT1 esophageal adenocarcinoma treated by esophagectomy without induction therapy were identified. Depth of invasion was subdivided into invasion into the lamina propria (LP), into the inner muscularis mucosae, between the inner and outer muscularis mucosae, and into the outer muscularis mucosae (OMM), with comparison with tumors invading the inner one third of the submucosa (SM-1). Patient and tumor characteristics were compared among the 5 groups using the chi(2) test or the Kruskal-Wallis test. Survival was estimated using the Kaplan-Meier method and compared using the log-rank test. The prognostic effect of depth of invasion on survival was assessed with Cox proportional hazards analysis. Results: Depth of invasion was LP (n = 68), inner muscularis mucosae (n = 38), BMM (n = 11), OMM (n = 33), and SM-1 (n = 35). There was no significant difference in sex or age among groups. One of 150 patients with intramucosal adenocarcinoma (0.7%; LP, pN2) and 3 of 35 patients with SM-1 (8.6%; all pN1) had nodal disease. There were no significant differences in survival among the groups. Conclusions: Depth of invasion relative to the duplicated muscularis mucosae for tumors restricted to the mucosal compartment does not affect survival in Barrett esophagus-related superficial adenocarcinoma. Patients with SM-1 tumor had survival similar to those patients with tumor invasion into the OMM.