Prognostic And Predictive Value Of Tumour Budding In Stage Ii Colorectal Carcinoma

3605 Background: High-grade tumor budding (HGTB) is reported to be an independent adverse prognostic factor in colorectal cancer (CRC). Its presence is not routinely assessed by pathologists due to uncertainties about its clinical value, risk group thresholds, and the reproducibility of its assessment. Moreover, the benefit of chemotherapy in stage II CRC with HGTB remains to be demonstrated. This study aimed to (1) confirm the prognostic significance of HGTB in stage II CRC (2) determine the optimum threshold for HGTB reporting and (3) determine the responsiveness of stage II CRC with HGTB to chemotherapy. Methods: Whole slide images from CRC resections of 979 QUASAR trial patients (majority stage II) were evaluated for tumor budding as per the method of Ueno (2002). A tumor bud was defined as a single cell or a cluster of u003c 5 cells on a hematoxylin and eosin stained section. The highest tumor bud count per 1.23 mm2field was recorded. The optimal cutoff for HGTB was determined by maximal likelihood metho...