Tumor Budding in Colorectal Carcinoma: Translating a Morphologic Score Into Clinically Meaningful Results.

CONTEXT - Tumor budding has received increasing recognition as an important independent prognostic factor in colorectal carcinoma. Prominent tumor budding in adenocarcinoma arising in a polyp has been shown to be a risk factor for lymph node involvement. The variability in methods used for evaluating tumor budding in different studies and lack of standardized guidelines have impeded routine inclusion of tumor budding in pathology reports. This changed last year with consensus guidelines based on the International Tumor Budding Consensus Conference (ITBCC). These guidelines have been included in the recent College of American Pathologists (CAPs) Colorectal Cancer Protocol. The consensus methodology will allow uniform reporting of this finding, but challenges in interpretation in the setting of intense inflammation, fibrosis, or gland fragmentation need to be addressed in future guidelines. OBJECTIVE - To provide a brief overview of the known clinical significance of tumor budding in colorectal carcinoma and discuss the practical aspects of its implementation on a routine basis. DATA SOURCES - English-language pathology literature. CONCLUSIONS - Tumor budding has been shown to be an independent prognostic marker in colorectal carcinomas and the routine reporting of tumor buds is now advocated by using the approach outlined by the ITBCC guidelines. Tumor budding is included in the CAP protocol as a recommended element. Presence of prominent tumor budding in an adenocarcinoma in a polyp may have implications for management, such as additional resection, while it serves as a prognostic factor in other settings.