What is the leading cause of bladder cancer?

Cigarette smoking is the leading cause of bladder cancer. Chemicals in cigarette smoke damage the cells that line the bladder, making them more likely to become cancerous. Cigarette smoke also contains arsenic, a known carcinogen. People who smoke are four times more likely to get bladder cancer than people who don't smoke. The risk of bladder cancer increases with the number of cigarettes smoked per day and the number of years a person has smoked. Quitting smoking can reduce the risk of bladder cancer, even for people who have smoked for many years.