Prognostic value of tumor budding in muscle-invasive urothelial carcinoma of the bladder

Bladder cancer is a common malignancy of the urogenital tract worldwide. Almost 20–30% of new cases are muscle-invasive, a complex pathology with significant clinical and biological variability. Despite treatment advances, predicting disease progression remains challenging due to the limitations of traditional prognostic factors. Identifying new markers, such as tumor budding (TB), could offer a promising breakthrough. The aim of this study was to evaluate TB in muscle-invasive urothelial carcinoma (UC) of the bladder and assess its clinicopathological and prognostic significance. We conducted a cross-sectional analytical study of 84 cases of muscle-invasive UC of the bladder. TB was assessed based on the 2016 International Tumor Budding Consensus Conference guidelines and correlated with clinicopathological features and patient survival. The study included 77 men and 7 women, with a mean age of 68.13 ± 9.41 years. Histologically, ulcerative proliferative and infiltrative features were most common (58%), and high-grade tumors accounted for 92.9% of cases. Tumors were mainly classified as pT4a (40.5%), with lymph node metastasis observed in 34.3%. The mean overall survival was 23.07 ± 1.9 months. TB was present in 41.7% of cases, with Bd1 in 9.5%, Bd2 in 16.7%, and Bd3 in 15.5% of UCs. Significant correlations were found between TB and the pattern of the invasive front (p = 0.002), presence of carcinoma in situ component (p = 0.024), vascular emboli (p = 0.020), lymphatic emboli (p = 0.044), perineural invasion (p = 0.012), and parietal wall infiltration (p = 0.006). These findings suggest that TB serves as an independent histoprognostic predictor of the aggressiveness of muscle-invasive UC, warranting its inclusion in pathology reports and treatment protocols. However, to further validate these findings, large-scale prospective studies with standardized methods for evaluating TB are required.