Advances in the diagnosis of urothelial neoplasia

Urothelial neoplasia is a unique cancer in that is consists of a spectrum of tumors with different biologic behaviors. The most common urothelial neoplasm is the low grade superficial papillary carcinoma or papilloma which may recur numerous times but does not result in significant morbidity or mortality. A variant of the superficial papillary carcinoma, which represents approximately 10% of the tumors, is the noninvasive papillary neoplasm which progresses to a less differentiated invasive transitional cell carcinoma (TCC). Considerable effort has been directed at identifying which of the superficial well differentiated papillary tumors will persist, recur, and progress to invasive cancer. Current approaches to identifying such tumors include cytogenetics, molecular biology, and flow cytometric DNA analysis. In the final group of bladder carcinomas, the high grade invasive neoplasms, evidence suggests that these life-threatening tumors arise de novo without identifiable precursors. Unfortunately, 75% to 90% of invasive TCCs are classified in this group, with the remaining minority progressing from preexisting recurrent superficial papillary carcinomas. Obviously the biologic behavior of these aggressive poorly differentiated tumors is life-threatening, and application of traditional diagnostic procedures and new technologies need to be directed at early diagnosis.