ECLNI-MCCan Extracapsular Lymph Node Involvement be a Tool to Fine-tune UICC TNM 7th Edition for Esophageal Carcinoma?

The classification of carcinoma of the esophagus has undergone a major modification between the UICC sixth (TNM-6) and TNM-7 edition. Regional lymph nodes (N) are now subdivided by the number of involved lymph nodes (pN0, 0; pN1, 1-2; pN2, 3-6; pN3 > 6), and distant metastasis (M) has been simplified to M1 rather than subdivided by location [1]. Nevertheless, TNM-7 doesn't take into consideration the morphologic characteristics of the metastatic lymph node itself. Since our first publications showing a negative relationship between presence of extracapsular lymph node involvement (EC-LNI) and survival [2], little has been published about the prognostic impact of this specific characteristic . In our latest publication "Can extracapsular lymph node involvement be a tool to fine-tune pN1 for adenocarcinoma in UICC TNM 7th Edition?" [3], the investigators found a significant survival benefit for adenocarcinoma without extracapsular lymph node involvement in pN1 (= 1-2 positive lymph nodes) as compared to N2-N3 disease, treated by primary surgery. Moreover, pN1 patients with extracapsular lymph node involvement (EC-LNI) showed a survival that was comparable to patients with more than 2 positive lymph nodes (i.e. stage IIIB). These findings may have important consequences for future TNM adaptations. The aim of this study is to validate our results on a larger, multicentric cohort, and if possible make recommendations and possible fine-tuning for a future TNM adaptation, including the characteristics of the metastatic lymph node itself, being intra- or extracapsular. Furthermore the investigators want to examine if these effects are valid in pre-treated patients, i.e. surgery after neoadjuvant chemo(radiation) therapy. Although these patients are not incorporated in the current TNM classification, future adaptations to the TNM classification system will also examine the effects of neoadjuvant therapy (cfr. Rice/Blackstone WECC -Worldwide Esophageal Cancer Collaboration).