Tumor budding as a new histological parameter in the metastasis of colorectal cancer

Introduction:The presence of tumor budding, i.e.,single cancer cells or a nest of poorly differentiated cells at the front of tumor invasion appears to be a new histopathological indicator of increased aggressiveness of colorectal carcinoma. Purpose: The aim of this work was a retrospective evaluation of the invasion front (tumorbudding, vascular invasion,and lymphocytic infiltration) in postoperative biopsies of patients with colorectal carcinoma and analysis of the 5-year survival. Materialsand methods:The study was based on the material received after surgical treatment of 164 patients with colon cancer. Tissue was obtained directly following tumor resection, fixed in 10% formaldehyde and embedded in paraffin blocks using a routine method by melting with paraffin at a temperature of 56º C. These samples were then routinely stained with haematoxylin and eosin and underwent a histopathological evaluation, with particular attention being paid to the invasion front of the tumor. The immunohistochemical expression of cytokeratin 20 was also evaluated using anti-human CK20 monoclonal antibody (clone Ks.20.8, Dako, Poland). Results: Tumor budding was found in 124 out of 164 patients. Statistical analysis showed a correlation between the presence of tumor budding TB and depth of invasion (pT), lymph node metastasis, distant metastasis, lymphocytic infiltration,and vascular invasion. The cumulative five-year survival correlated with the lack of tumor budding and vascular invasion, as well as a decrease in lymphocyticinfiltration.