Assessment of Tumor Budding in Colorectal Carcinoma by Cytokeratin Staining

Background: Tumor budding has been receiving increasing recognition in many studies, as an important independent prognostic factor in colorectal carcinoma (CRC). In histopathological reporting of CRC, it is defined as the presence of single tumor cell or small clusters of up to 4 cells in the advancing edge of the tumor stroma.Objectives: We aim to determine the frequency of tumor budding by cytokeratin staining, in relation to the depth of invasion, lymph node involvement, perineural invasion and tumor grade in colorectal carcinoma.MaterialS and Methods: This descriptive cross sectional study was carried out from November 2022 till April 2023. During these six months, 62 hemi-colectomy specimens of colorectal carcinoma, received in histopathology lab were included in this study. The samples belonged to the patients who were biopsy proven cases of colorectal carcinoma and those who were not given any pre-operative therapy. The age range was from 20 to 80 years including both genders. After processing the tumor sections were examined under microscope, on both conventional stains and the Pan-Cytokeratin (AE1/AE3) stain. The results were interpreted by consultant histopathologists for tumor budding score. Tumor buds less than 10 per high power field was considered as low score. 10 and more buds per high power field were considered as high score.Results: When tumor grade and depth of invasion was compared to tumor budding score, the comparison was not statistically significant with p value of 0.06 and 0.937 respectively, whereas its relationship with lymph node involvement and perineural invasion was found to be statistically highly significant with p value of < 0.001.Conclusion: This study concluded that tumor budding has a statistically significant relationship with lymph node metastasis and perineural invasion, but not with tumor grade and depth of invasion (T stage).Keywords: Colorectal carcinoma, Drade, Lymph node, Pan-cytokeratin, Perineural invasion, Stage.