Bladder Cancer What is bladder cancer? Bladder cancer occurs when there are abnormal, cancerous cells growing in the bladder. The American Cancer Society (ACS) estimated 73,000 diagnosed cases of bladder cancer in 2013. Bladder cancer affects men about 3 times more often than women, and it occurs in whites twice as often as in African-Americans. The risk of bladder cancer increases with age—over 90 percent of people who are diagnosed with it are older than 55. The bladder is a triangle-shaped, hollow organ located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to 2 cups of urine for 2 to 5 hours.