Contribution of bladder cancer pathology assessment in planning clinical trials.

Bladder cancer is a heterogeneous disease that demonstrates a wide spectrum of histologic features. The modern classification of bladder cancer is largely based on pathologic analysis, which assesses tumor grade, stage, type, size, and other features that are essential for understanding the biological behavior of bladder cancer. Bladder cancers with similar histologic features are likely to show comparable responses to a new therapeutic agent in clinical trial. Furthermore, pathologic analysis also evaluates the quality of tissue samples in clinical trial to ensure the integrity of various molecular tests. In spite of the emerging role of genomic and molecular studies, pathology remains the cornerstone in the diagnosis, prognosis, and treatment of bladder cancer. Herein, the pathologic considerations for bladder cancer clinical trial planning are reviewed.