Most types of urinary system cancers are much more common in men than in women. For example, in 2009, which is the most recent year for which statistics are available, it is estimated that about 74 percent of the people who were diagnosed with bladder cancer were men and about 61 percent of the people who were diagnosed with kidney cancer were men. Researchers have surmised that men are more likely than women to encounter certain risk factors for this type of cancer. For example, they are more likely to have jobs that put them in close contact with hazardous chemicals. They are also more likely to be smokers. The treatment for some types of urinary system cancers is slightly different in men because of the difference in anatomy between the sexes. For example, if the bladder must be surgically removed in the case of bladder cancer, the prostate will also need to be removed at the same time. If his prostate is removed, a man will no longer be able to produce semen. One potential side effect of this type of surgery in men is nerve damage that causes impotence, but this damage is not always permanent. Because of the difference in the anatomy of the urethra in men and women, the treatment of urethral cancer varies depending on the person's gender. In men, the prostate or the penis can be affected by urethral cancer.