The bladder is a muscular organ in the lower abdomen that stores urine until it can be removed (excreted) from the body.
Bladder cancer is a disease in which certain cells in the bladder become abnormal and multiply uncontrollably to form a tumor.
The most common type of bladder cancer, called non-muscle invasive bladder cancer (NMIBC), involves cells lining the inside of the bladder. NMIBC generally does not spread to other tissues (metastasize), but it often does recur after it has been treated.
The other type, called muscle-invasive bladder cancer (MIBC), involves cells of the muscle wall of the bladder. MIBC generally does metastasize and is often life-threatening.