While the cause of anal cancer is not always known, there are risks that may increase the chance of developing anal cancer. People infected with the human papillomavirus (HPV) have a greater risk of developing anal cancer, and there is also an increased risk for those who:
- Have many sexual partners
- Are over the age of 50
- Have anal fistula
- Have receptive anal intercourse
- Smoke cigarettes
People with suppressed immune systems or who take medication that suppresses their immune system, are also at risk for developing anal cancer.