Causes of Penile Cancer
The exact cause of penile cancer is not known but there are several risk factors.
Human papilloma virus (HPV)
HPV is a common infection and is passed from one person to another by sexual contact. Around 8 out of 10 people (80%) in the UK will be 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. A number of research studies have tried to establish the link between penile cancer and HPV. These studies show that the number of men with penile cancer who have evidence of HPV infection is around 5 out of 10 (47%). HPV also increases the risk of cervical, anal, vulva and vaginal cancers.
HPV is commonly called the ‘wart virus’ because some types 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, although other types may also be related too. HPV 16 and 18 do not usually cause genital warts but there is evidence that men with a history of genital warts have an increased risk of penile cancer.
It is rare for men below the age of 40 to get penile cancer. Most cases are in men aged over 60.
Men who smoke may be more likely to develop cancer of the penis. There are chemicals that cause cancer (benzyrene) in cigarettes. Researchers believe that these may damage the DNA of cells in the penis and increase the risk of developing cancer.
Cells in the lining of the penis, called Langerhans cells, help fight disease. These cells do not work so well in smokers and can’t fight off viruses as well as they do in non smokers. So if you smoke and have a high risk type of HPV Infection you may be more at risk of penile cancer.
Having a weakened immune system
If you have a weakened immune system, you have an increased risk of penile cancer (and other cancers). Your immune system may be weakened if you have HIV or AIDS, or because you need to take drugs to damp down your immune system after having an organ transplant.
Circumcision is a small operation to remove part, or all, of the foreskin. Male babies may be circumcised at birth for hygiene or religious reasons. The age you are circumcised appears to affect the risk of penile cancer.
- Men who are circumcised as babies appear to be less likely to develop 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
However, it is important to remember that circumcision is only one risk factor for this type of cancer. Other risk factors such as smoking and HPV infection are more important.
Build up of secretions under the foreskin
Uncircumcised men should regularly pull back their foreskin to clean under it. If they don’t do this, secretions and dead skin cells can build up. This thick, often bad smelling substance (known as smegma) can cause irritation and inflammation of the penis. Men who have difficulty drawing back their foreskin (a condition called phimosis) may get a build up of smegma. Men with phimosis have a risk of penile cancer that is 5 to 11 times higher than other men. But because penile cancer is rare their risk is still small.
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 known as PUVA and can also be a cancer treatment. Men who have had PUVA appear to have an increased risk of penile cancer.