The Role of Tumour Budding as a Prognostic Factor in Primary Invasive Ductal Carcinoma of Breast.

Background: Tumor budding is considered as an essential step in invasion and as a poor prognostic factor in carcinoma.It is used as the main prognostic factor in colon cancer but it is now gaining popularity in other tumor types. Objectives of the study was to determine tumor budding and categorize it into low grade and high grade in primary invasive breast cancer patients and to determine the association of tumor budding with clinicopathological characteristics. An attempt was also made to compare cytokeratin expression in intra- tumoral and budding sites. Method: It was an observational-analytical study including 50 cases of surgically resected modified radical mastectomy specimens diagnosed as invasive breast carcinoma in the tertiary care hospital from October 2018 to March 2020. Tumor buds were counted in H&E and IHC stained sections in 10 high power fields. IHC marker used was pan cytokeratin. Cases were classified into low tumor budding and high tumor budding. Correlation of tumor budding was done with all the established clinicopathological characteristics. Cytokeratin expression was compared in tumor proper and budding sites. Results: Among the 50 casesof invasive breast carcinoma, 24 cases showed high tumor budding (>4/10HPF) and 26 cases showed low tumor budding (?4/10HPF). High tumor budding was seen with larger size of the tumor, higher primary tumor staging, higher lymph node staging, presence of lymphovascular invasion, lymph node involvement and presence of necrosis with a significant correlation. Also cytokeratin expression was similar in tumor proper and budding sites in 92% of the cases. Interpretation & Conclusion: Tumor budding showed significant correlation with tumor size, primary tumor staging, lymph node staging, lymph node involvement, lymphovascular invasion and tumor necrosis. Thus it can be considered as a significant prognostic factor in the invasive breast carcinoma and can be incorporated in the reporting protocol for breast cancer.