Clinicopathologic Features of Submucosal Esophageal Squamous Cell Carcinoma

Background The prognoses of submucosal esophageal squamous cell carcinoma patients vary. Patients with favorable prognoses may receive less invasive or nonsurgical interventions, whereas patients with poor prognoses or advanced esophageal cancer may require aggressive treatments. We sought to identify prognostic factors for patients with submucosal esophageal squamous cell carcinoma, focusing on lymph node metastasis and recurrence. Methods We included 137 submucosal esophageal squamous cell carcinoma patients who had undergone transthoracic esophagectomy with systematic extended lymph node dissection. Submucosal tumors were classified as SM1, SM2, and SM3 according to the depth of invasion. Prognostic factors were determined by univariable and multivariable analyses. Results Lymph node metastasis was observed in 18.8%, 30.5%, and 50.0% of SM1, SM2, and SM3 cases, respectively. The overall 5-year recurrence rate was 21.9%; the rates for SM1, SM2, and SM3 tumors were 9.4%, 18.6%, and 34.8%, respectively. The SM1 tumors all recurred locoregionally; distant metastasis occurred in SM2 and SM3 cases. The 5-year overall survival rates were 83%, 77%, and 59% for SM1, SM2, and SM3 cases, respectively. On univariable analysis, lymph node metastasis, depth of submucosal invasion (SM3 versus SM1/2), and tumor location (upper thoracic versus mid/lower thoracic) were poor prognostic factors for overall survival. Multivariable Cox regression analyses identified depth of submucosal invasion (hazard ratio 2.51, 95% confidence interval: 1.37 to 4.61) and tumor location (hazard ratio 2.43, 95% confidence interval: 1.18 to 4.63) as preoperative prognostic factors. Conclusions Tumor location (upper thoracic) and infiltration (SM3) are the worse prognostic factors of submucosal esophageal squamous cell carcinoma, but lymph node metastasis is not a predictor of poorer prognosis.