What Is High Grade Urothelial Carcinoma?

Urothelial carcinoma—also called transitional cell carcinoma—is a form of cancer that begins in the cells that line the bladder. When cells of this cancer show certain structural changes, they are classified as high-grade.

The Facts

• According to the American Cancer Society, urothelial carcinoma accounts for more than 97 percent of all bladder cancers.

High-Grade Urothelial Carcinoma

• Cancer specialists (oncologists) split urothelial carcinomas into two categories. Low-grade carcinomas have cells that look similar to normal cells, while high-grade carcinomas have cells that show serious abnormalities, according to the ACS.

Growth Rate and Danger

• Typically, high-grade urothelial carcinomas grow relatively quickly and present a greater cancer danger than low-grade carcinomas.

Additional Factors

• In addition to classifying carcinomas as high- or low-grade, oncologists predict the seriousness of each case by determining whether it has spread to (invaded) other layers of bladder tissue. As a rule, invasive cancers pose more health problems and treatment difficulties. Both high- and low-grade carcinomas can be invasive.

Invasive Urothelial Carcinomas

• Invasive urothelial carcinomas may spread from the bladder lining to the bladder muscle as well as to associated lymph nodes and nearby organs, according to the National Cancer Institute.