Depth of Muscularis Propria Invasion Does Not Prognosticate Survival in T2 Esophageal Adenocarcinoma

Aim: Although tumor depth of invasion is strongly associated with risk of lymph node metastasis and long-term survival in patients with esophageal adenocarcinoma, the significance of differential T2 invasion (inner circular layer versus outer longitudinal layer) is unknown. The current study was undertaken to explore the hypothesis that greater T2-specific depth of invasion is associated with inferior long-term outcomes in patients with esophageal adenocarcinoma treated with esophagectomy. Patients and Methods: Demographic, treatment, and outcome data were collected for patients with resected pT2N0-3M0 esophageal adenocarcinoma treated between 2005 and 2015 pooled from four U.S. academic medical centers. Two blinded pathologists evaluated depth of muscularis propria tumor invasion. Univariate and Cox proportional hazard regression analyses were performed to identify prognostic factors for overall (OS) and disease-free (DFS) survival, and Kaplan-Meier analysis to compare survival differences specific to prognostic factors. Results: A total of 84 patients were identified for analysis (53 with circular invasion; 31 with longitudinal invasion), with a median age of 66 years. Sixty percent of patients (50/84) received induction therapy prior to esophagectomy. The median OS and DFS was 58 months (95% confidence interval(CI)=42 months-not reached) and 27 months (95% CI=13.7-66 months) respectively. Depth of muscularis propria invasion did not correlate with OS or DFS on univariate (p=0.42; and p=0.34, respectively) or multivariate (p=0.15 and p=0.21, respectively) analysis after adjustment for age, nodal status, perineural invasion, and tumor grade. These findings did not vary by induction therapy status. Conclusion: Depth of muscularis propria invasion does not appear to correlate with survival in patients with esophageal adenocarcinoma.