Lymph node metastatic patterns and its clinical significance for thoracic superficial esophageal squamous cell carcinoma

BACKGROUND AND OBJECTIVES: The optimal therapeutic method for patients with superficial esophageal squamous cell carcinoma (sESCC) remains to be established. METHODS: Clinical data of all the patients from 2002 to 2014 who underwent curative esophagectomy and three-field lymphadenectomy for thoracic sESCC were collected based on a prospectively-maintained database. The pattern of lymph node metastasis was analyzed based on the depth of tumor invasion, tumor location and surgical fields. RESULTS: The involved lymph node region was associated to the tumor location, however, upper mediastinal and perigastric region was the most vulnerable region. The incidence of lymph node metastasis increased with the depth of tumor invasion. No lymph node involvement was found in tumors invading proper mucosa (M2), while the pattern of positive lymph nodes in tumors invading the deepest 1/3 submucosa was similar to that in advanced ESCC. Lymphatic invasion, tumor location and upper mediastinal lymph node involvement were independent predictors for cervical lymph node metastasis. For patients without lymphatic invasion, the positive predictive value of upper mediastinal lymph node metastasis for positive cervical lymph node was low (0 ~ 25%), while the negative predictive value was extremely high, wherever the tumor located (93.8 ~ 100%). CONCLUSIONS: Tumors invading till proper mucosa was the best indication for endoscopic mucosa resection. Mediastinal-abdominal lymphadenectomy was essential for sESCC invading beyond proper mucosa. For those without lymphatic invasion, cervical lymphadenectomy might be avoided in case of negative upper mediastinal lymph node.