Does bladder cancer spread quickly?

Bladder cancers are graded as either low-grade or high-grade. The grade is assigned by a pathologist who evaluates the cancer cells under a microscope and determines the grade by looking at the cells. High-grade bladder cancer cells are considered more aggressive and have the ability to spread and metastasize to other areas of the body. Low-grade bladder cancers typically reside on the surface of the bladder and almost never spread or metastasize.

Bladder cancer is staged based upon the depth of invasion into the bladder wall. Most bladder cancers are considered non-muscle invasive, while approximately 25% of bladder cancers are muscle invasive.

While most bladder tumors are cancerous, there are benign bladder tumors. Some of these benign tumors have a similar appearance to malignant tumors and the role of biopsy remains very important. Some examples of benign bladder tumors include a bladder papilloma and a nephrogenic adenoma.