BACKGROUND: Mucosal (T1a) and submucosal (T1b) squamous cell carcinoma of the esophagus (ESCC) have often been analyzed together and are staged as the same category in the UICC/TNM staging system. The difference in surgical outcomes between T1a and T1b ESCC therefore remains unclear. The purpose of this study was to examine the differences in surgical outcomes between T1a and T1b ESCC, and to investigate the prognostic factors in T1 ESCC. METHODS: A prospectively maintained database identified 145 previously untreated patients with pT1 ESCC who underwent radical transthoracic (n = 134) or transhiatal esophagectomy (n = 11). Median follow-up was 108 months. RESULTS: Of the 145 patients, 35 (24 %) had pT1a cancer and 110 (76 %) had pT1b cancer. Lymph node metastasis was present in 45 patients (31 %): 3 patients with pT1a cancer and 42 patients with pT1b cancer (P = 0.0003). The 5-year survival rate for the whole group was 77 %. The 5-year survival rate of the T1a patients was 94 % compared with 72 % for the T1b patients (P = 0.0282). In multivariate analysis, only the depth of tumor invasion (pT1a vs. pT1b) was an independent prognostic factor (hazard ratio 2.358; 95 % confidence interval 1.009–5.513; P = 0.0477). CONCLUSIONS: After esophagectomy, the prognosis of patients with pT1b ESCC is significantly worse than that of patients with pT1a ESCC. Infiltration into the submucosa is the only independent prognostic factor affecting survival. These findings suggested that T1a and T1b ESCC could be staged separately in the next version of UICC/TNM staging system.
BACKGROUND: Mucosal (T1a) and submucosal (T1b) squamous cell carcinoma of the esophagus (ESCC) have often been analyzed together and are staged as the same category in the UICC/TNM staging system. The difference in surgical outcomes between T1a and T1b ESCC therefore remains unclear. The purpose of this study was to examine the differences in surgical outcomes between T1a and T1b ESCC, and to investigate the prognostic factors in T1 ESCC. METHODS: A prospectively maintained database identified 145 previously untreated patients with pT1 ESCC who underwent radical transthoracic (n = 134) or transhiatal esophagectomy (n = 11). Median follow-up was 108 months. RESULTS: Of the 145 patients, 35 (24 %) had pT1a cancer and 110 (76 %) had pT1b cancer. Lymph node metastasis was present in 45 patients (31 %): 3 patients with pT1a cancer and 42 patients with pT1b cancer (P = 0.0003). The 5-year survival rate for the whole group was 77 %. The 5-year survival rate of the T1a patients was 94 % compared with 72 % for the T1b patients (P = 0.0282). In multivariate analysis, only the depth of tumor invasion (pT1a vs. pT1b) was an independent prognostic factor (hazard ratio 2.358; 95 % confidence interval 1.009–5.513; P = 0.0477). CONCLUSIONS: After esophagectomy, the prognosis of patients with pT1b ESCC is significantly worse than that of patients with pT1a ESCC. Infiltration into the submucosa is the only independent prognostic factor affecting survival. These findings suggested that T1a and T1b ESCC could be staged separately in the next version of UICC/TNM staging system.