High-grade urothelial carcinoma is a type of bladder cancer that has a high risk of becoming aggressive and progressing, as stated by the John Hopkins University Department of Pathology. It is more likely to recur in the bladder, invade the muscle wall or spread to other parts of the body than low-grade bladder cancers, according to the National Cancer Institute. In the United States, most bladder cancer deaths are from high-grade tumors.
As of 2015, bladder cancer is the third most common cancer in men and the 11th- most-common cancer in women, according to the National Cancer Institute. More than 75 percent of new cases and 65 percent bladder cancer deaths each year are men.
Urothelial carcinoma is the most common type of bladder cancer and occurs in 90 percent of the cases, as noted by the John Hopkins University Department of Pathology. It is further divided into two subtypes: superficial cancers and muscle tumors. About 70 percent of patients are first diagnosed with a superficial tumor and most of these are noninvasive papillary urothelial carcinoma. About 4 to 8 percent will go on to invade other areas, with those that are identified as high-grade most likely to progress to the muscle wall. The high grade urothelial carcinomas are treated more aggressively than the low-grade tumors.