Bladder cancer is a type of cancer that begins in the cells lining the bladder, which is a hollow organ located in the pelvis that stores urine produced by the kidneys. Bladder cancer is one of the most common cancers of the urinary tract and can occur at any age, although it is more common in older adults. Bladder cancer is a type of cancer that begins in the cells of the bladder, which is the organ responsible for storing urine. It is one of the most common cancers of the urinary tract.