Background: Lymph node status is an important prognostic parameter in esophageal carcinoma and an independent predictor of survival. Distribution of metastatic lymph nodes may vary with tumor location, tumor histology, tumor invasion depth and neoadjuvant therapy. Surgical strategy depends on the distribution pattern of nodal metastases but consensus on the extent of lymphadenectomy differs worldwide. Especially for adenocarcinoma the distribution of lymph node metastases has not yet been described in large series. Aim of the present study is to evaluate the distribution of lymph node metastases in esophageal carcinoma specimens following transthoracic esophagectomy with at least a 2-field lymphadenectomy.

Methods: The TIGER-study is a multinational observational cohort study. All patients with a resectable esophageal or gastro-esophageal junction carcinoma in whom a transthoracic esophagectomy with a 2- or 3-field lymphadenectomy is performed in participating centers will be included. All lymph node stations will be excised and separately sent for pathological examination. Cluster analysis will be performed to identify patterns of metastases in relation to tumor location, tumor histology, tumor invasion depth and neoadjuvant therapy.

Conclusion: TIGER will provide a roadmap of the location of lymph node metastases in relation to tumor histology, tumor location, invasion depth, number of lymph nodes and lymph node metastases, pre-operative diagnostics, neo-adjuvant therapy and survival. Patient-tailored treatment can be developed on the basis of these results, such as the the optimal radiation field and extent of lymphadenectomy based on the primary tumor characteristics.