That is why smoking is considered a risk factor for penile cancer. Other risk factors are the infection with HPV, a poor hygiene,smegma , phimosis, HIV infection, age and the treatment od psoriasis with UV light.There are no documented proofs whether or not circumcision affects in a positive or negative way penis cancer incidence.

Penis cancer is a rare form of cancer and it appearsmostly to people living in Africa where penis cancer incidence can get to 10% of the total number of cancer cases and it also leads to death in more than 74% of the cases. In America and Europe penis cancer incidence is a lot reduced and there may be one case for 100,000 people. Its percentage is only 0.2% of all cancer cases and the number of deaths caused by this type of cancer is under 0.1% of all cases in this geographic region.
As usual when it comes to cancer, the exact cause of this disease is not yet known and even if specialists have researched it for ages they still do not know why it appears in a certain organ and in a certain person. Even if you do whatever you can to avoid all risk factors there are no guarantees that you will not have cancer in the future. Any way - this rare type of cancer is treated just like any other type, by surgery, chemotherapy, radiation therapy. In most of the cases this is the primary location of the cancer and very rarely it is the location of metastatic cancer spread to the penis from another organ.

But although it is very rare and very obvious when it appears because of the symptoms showing on the outside of the people's bodies, the overall death rate id somewhere around 50%, which is pretty high. My guess is that the main problem is the fact that people come to the doctor in very late stages of the cancer and the disease is already so spread that it can't be cured. That happens almost in all cases when the cancer occurs in those parts of the body that make people ashamed to go to a hospital. More details about it on www.wikipedia.org and www.cancer.gov.