The exact cause of penile cancer is not known but there are several risk factors.
Having any of these risk factors doesn’t mean that you will definitely develop cancer.
Human papilloma virus (HPV)
HPV is a common infection that spreads through close skin-to-skin contact, usually during sexual activity including oral sex.
Around 8 out of 10 people (80%) in the UK get infected with the HPV virus at some time during their lifetime. For most people the virus causes no harm and goes away without treatment. But men with human papilloma virus have an increased risk of developing cancer of the penis.
Around 6 out of 10 (60%) penile cancer cases are caused by HPV infection. Some types of HPV cause genital warts.
There are over 100 types of HPV and each one has a number. The main types of HPV found in men with penile cancer are HPV 16 and 18. There may be other types too.
In a Danish study, men who had never used condoms compared to men who had used condoms had more than double the risk of penile cancer. This may be because condoms reduce the risk of HPV infection.
Circumcision may reduce the risk of HPV infection of the penis.
Penile cancer is more common in men aged 50 or over. It is rare in men under the age of 40.
Having a weakened immune system
The immune system fights infection and diseases like cancer in the body. You may be at higher risk of penile cancer if you have a weakened immune system, and other cancers.
HIV infection or AIDS may lower the immune system. Some drugs after an organ transplant may also weaken the immune system.
Circumcision is a small operation to remove part, or all, of the foreskin. Uncircumcised men may sometimes find it difficult to draw back their foreskin. This is called phimosis. Men with phimosis have a higher risk of penile cancer than other men.
The reason for this is not clear. It may relate to other known risk factors caused by phimosis, including a build-up of secretions under the foreskin. Smegma is a cheese-like substance made up of dead skin cells that can build up under a tight foreskin. This can cause irritation and inflammation of the penis if it is not cleaned on a regular basis.
Male babies may have a circumcision at birth for social or religious reasons. The age of circumcision can affect the risk of penile cancer:
- men who are circumcised as babies appear to be less likely to get penile cancer.
- men who are circumcised in their teens seem to have some protection from penile cancer.
- circumcision in adulthood seems to make no difference to a man’s risk of penile cancer.
Remember that not being circumcised is only one risk factor for this type of cancer. HPV infection is more important.
Psoriasis (pronounced sore-eye-ah-sis) is a chronic skin condition. You can't catch it from another person. It is sometimes treated with a combination of a drug called psoralen and light therapy (phototherapy). This treatment is called PUVA and can also be a cancer treatment. Men who have had PUVA appear to have an increased risk of penile cancer.
Other possible causes
Stories about potential causes are often in the media and it isn’t always clear which ideas are supported by evidence. There might be things you have heard of that we haven’t included here. This is because either there is no evidence about them or it is less clear.