What Is Bladder Cancer? Cancer is the growth of abnormal cells in the body. Bladder cancer typically begins in the inner lining of the bladder, the organ that stores urine after it passes from the kidneys. Most bladder cancers are caught early, when treatments are highly successful and the disease has not spread beyond the bladder. But bladder cancer tends to come back, so regular check-ups are important. Warning Sign: Blood in Urine Blood in the urine can be a sign of bladder cancer, either visible to the eye or picked up by routine testing. The urine may look darker than usual, brownish, or (rarely) bright red. Most commonly, blood in the urine is not caused by cancer, but by other causes. These include exercise, trauma, infections, blood or kidney disorders, or drugs, such as blood thinners. Warning Sign: Bladder Changes Bladder symptoms are more likely to come from conditions other than cancer. But bladder cancer can sometimes cause changes to bladder habits, including: 1. Needing to go, with little or no results 2. Having to go more often than usual 3. Painful urination 4. Difficulty urinating Urinary tract infections or bladder stones can cause similar symptoms, but require different treatments. Types of Bladder Cancer The main types of bladder cancer are named for the type of cells that become cancerous. The most common is transitional cell carcinoma, which begins in the cells that line the inside of the bladder. Squamous cell carcinoma and adenocarcinoma are much less common. Stages of Bladder Cancer Stage 0: Cancer stays in the inner lining. Stage I: Cancer has spread to the bladder wall. Stage II: Cancer has reached the muscle of the bladder wall. Stage III: Cancer has spread to fatty tissue around the bladder. Stage IV: Cancer has spread to the pelvic or abdominal wall, lymph nodes, or distant sites such as bone, liver, or lungs.