Significance of Tumour Budding with Cytokeratin 20 Immunostaining as a Histopathological Prognostic Marker in Colorectal Adenocarcinoma EC03-EC07
Dr. Asha Mahadevappa,
#1036, 5th Main, 10th Cross, 1st Stage, Vijayanagar, Mysuru-570017, Karnataka, India.
Introduction: Tumour Budding (TB) in Colorectal Carcinoma (CRC) has been studied comprehensively and brought TB into the clinical dominion as an additional prognostic parameter. The tumour aggressiveness with poorer survival of CRC patient is linked to presence of Peritumoural Budding (PTB) at the invasion front and Intratumoural Budding (ITB) in the tumour centre.
Aim: To study and compare the scoring system of TB by Haematoxylin and Eosin (H&E) staining with immunohistochemistry (IHC) CK20 in resected specimens of CRC and, its relation between TB grades with known prognostic histopathological parameters of CRC.
Materials and Methods: The descriptive cross-sectional study was conducted in JSS Medical College and Hospital, Mysuru, Karnataka, India. A total of 50 cases of CRC were studied prospectively over a period of two years. Both H&E and IHC CK20 stained slides were studied. A total of 10 high power field (10 HPF) in invasive front were evaluated for PTB10HPF and within the tumour for ITB10HPF. The high dense area which had the maximum TB was taken as Hot Spot (HS). Continuous and cut off values of PTB, ITB and OTB (overall tumour budding) scores were compared in both H&E and IHC stained sections and also evaluated the association with various clinicopathological prognostic features.
Results: An increase in the number of TB (PTB-46%, ITB-72%, OTB-28%), via IHC was noted. On continuous scores PTB, ITB and OTB counts showed significant association with tumour stage, lymph node metastasis and lymphovascular invasion (all p<0.05). When cut-offs were applied these statistical significance were lost. The Pearson’s correlation coefficient confirmed that OTB is better in evaluating TB than PTB and ITB.
Conclusion: TB is a potential and potent histopathological prognostic forecaster of lymph nodal metastasis and a higher stage of tumour and allocates as a marker for stratification of patients into high risk categories in CRC. The TB in routine histopathology report should be advocated as H&E staining aided by IHC show significant association with histopathological parameters.