48 - Urinary tract, bladder, ureter and urethra

Summary

Introduction

Cancer of the bladder is common in males in many parts of the world, exhibiting moderate variation. Geographical differences may be partly dependent on whether so-called ‘benign papillomas’ of the bladder are included with the overtly malignant neoplasms. Tumors of the ureter are not common, but are sometimes associated with cancer of the bladder.

Histology, classification and diagnosis

In industrial states, most bladder cancers are transitional cell or urothelial carcinomas, squamous carcinomas being usually less than 10% of all tumors. Today, the term ‘benign’ papillomas is rarely used for bladder tumors, and these are now regarded as malignant. A predominance of squamous cell carcinomas is observed in areas where bladder cancer is related to schistosomiasis.

Descriptive epidemiology

Incidence (Fig. 48.1)

Rates are elevated in several industrialized countries, the highest being observed in Basel, Switzerland (27.8) and in Varese, northern Italy (27.3). In most registries in Europe and North America, rates are around 20. The lowest rates occur in India, with rates between 1.7 in Nagpur and 4.3 in Bombay, being slightly higher in Japan, between 6 and 10. Rates for U.S. blacks, around 10, are uniformly lower than in white Americans by some 50%, apparently due in part to under-reporting of early stage tumors (Schairer et al., 1988).