Depth of submucosal tumor infiltration and its relevance in lymphatic metastasis formation for T1b squamous cell and adenocarcinomas of the esophagus.

Background: Surgery for early esophageal carcinoma has been challenged by less invasive endoscopic approaches. Selecting patients in need for surgical intervention according to their risk of lymphatic spread is mandatory.

Objective: The aim of this study was to evaluate risk factors for lymphatic metastasis formation in T1b esophageal carcinomas.

Methods: Histopathological specimens following surgical resection for T1b esophageal carcinomas were reevaluated for overall submucosal layer thickness, depth of submucosal tumor infiltration, tumor length as well as lymphatic and vascular infiltration. Depth of tumor infiltration to overall submucosal thickness was divided in thirds (SM1, SM2, and SM3) and factors influencing lymphatic metastasis formation were assessed.

Results: A total of 67 patients with pT1b tumors were analyzed, including 36 adenocarcinomas (53.7 %) and 31 squamous cell carcinomas (46.3 %). Lymph node involvement was seen in 22.4 % (15/67) patients without significant differences between SM1 3/11 (27.3 %), SM2, 4/18 (22.2 %), and SM3 (8/38) (21.8 %) (p = 0.909) carcinomas. On binomial log-regression models, only lymphangioinvasion and tumor length >2 cm was significantly associated with lymph node involvement.

Conclusion: As depth of submucosal tumor infiltration did not correlate with the formation of lymph node metastases and in regard of the risk of lymphatic spread in these cases, surgical resection is warranted in pT1b carcinomas.