A New Metastatic Lymph Node Classification-based Survival Predicting Model in Patients With Small Bowel Adenocarcinoma: A Derivation and Validation Study

We modified current N staging into a 4-level staging system based on the number of metastatic LNs: N0, no LN metastasis; N1, 1-2 metastatic LNs; N2, 3-8 metastatic LNs, and N3, >8 metastatic LNs and set the least examined LN number to 17. A nomogram based on this staging showed great clinical usability than TNM staging for predicting the survival of SBA patients.