Prognostic value of tumor budding in gallbladder cancer: application of the International Tumor Budding Consensus Conference scoring system

Tumor budding (TB), a histopathological manifestation of epithelial–mesenchymal transition, is an important step in cancer invasion and metastasis development. TB has been considered a strong prognostic indicator in colorectal cancer. The International Tumor Budding Consensus Conference (ITBCC) scoring system is the standardized method used for patient outcome prediction in several human tumors. We investigated the clinicopathological implications and applicability of TB measured using the ITBCC scoring system in gallbladder cancer (GBC). The TB grades assigned to the 78 GBC patients were as follows: Bd1 (low TB), 41 (52.6%) patients; Bd2 (intermediate TB), 22 (28.2%) patients; and Bd3 (high TB), 15 (19.2%) patients. A higher TB grade correlated with a poorer histological differentiation (P < 0.000), higher pT category (P < 0.000), the involvement of surgical resection margin (P = 0.005), presence of nodal metastasis (P < 0.000), lymphatic and venous invasion (P < 0.000), and perineural invasion (P = 0.004). Univariate Cox regression analysis revealed that a poor histological grade, high pT category, lymphatic invasion, perineural invasion, and intermediate to high TB grades were associated with worse 5-year overall survival and disease-free survival. TB was not significantly associated with death or recurrence risk in multivariate Cox analysis. The interobserver agreement of TB grading was substantial. This study is the first to apply the ITBCC scoring system and suggest the prognostic value of TB in GBC.