Assessment of Tumour Budding in Colorectal Carcinoma and its Correlation with Pathological Staging among Patients undergoing Resection at a Tertiary Care Hospital in Kerala, India

Abstract

Introduction: Colorectal Carcinoma (CRC) is one of the most commonly diagnosed carcinomas and a significant cause of cancer-related deaths worldwide. The prognosis and treatment decisions rely on the Tumour, Node, Metastasis (TNM) Staging system. However, some tumours are classified as low-risk based on TNM stage exhibit adverse outcomes. Therefore, the search for additional prognostic factors is necessary. Tumour budding is an established independent prognostic factor, with high-grade tumour budding consistently linked to lymph node metastasis, local recurrence, and distant metastasis. Aim: To assess and grade tumour budding in CRC cases and examine its correlation with pathological staging. Materials and Methods: A cross-sectional study was conducted on 95 patients between December 2019 and December 2021 at Sree Gokulam Medical College and Research Foundation, Venjaramood, Trivandrum, India. Resected specimens from CRC patients were processed, and Haematoxylin and Eosin (H&E) slides were examined for tumour budding assessment. Ten individual fields were scanned under a 10x objective to locate the hotspot area with the maximum number of tumour buds. Tumour buds were then counted under a 40x objective in the selected hotspot area. Tumour budding was categorised as low (0-1 bud), intermediate (2-4 buds), or high (5 or more buds). Immunohistochemistry (IHC) analysis with Pancytokeratin was carried out when assessment with H&E slides alone was difficult. The correlation between tumour budding and pathological staging was evaluated, along with its association with various histopathological parameters. Results: The study included 95 patients, with a mean age of 68.22 years, comprising 58.95% males and 41.05% females. Low-grade tumour budding was observed in 42 (44.21%) cases, intermediate-grade budding in 34 (35.79%) cases, and highgrade tumour budding in 19 (20%) cases. There was a significant correlation between tumour budding and pathological staging (r-value=0.39) as well as the number of metastatic lymph nodes (r-value=0.34). The presence of lymph node metastasis and lymphovascular Invasion (LVI) showed a statistically significant association (p-value<0.01). Conclusion: Tumour budding grading is a valuable histopathological finding, as it increases with higher T stage and presence of nodal metastasis, aiding in the prediction of nodal metastasis and recurrence. It is positively correlated with pathological staging and the number of metastatic lymph nodes. Including tumour budding grade in the histopathology report can assist clinicians in assessing prognosis and making treatment decisions.