Anal Cancer: Risk Factors

What is a risk factor?

A risk factor is anything that may increase your chance of having a disease. Risk factors for a certain type of cancer might include smoking, diet, family history, or many other things. The exact cause of someone’s cancer may not be known. But risk factors can make it more likely for a person to have cancer.

Things you should know about risk factors for cancer:

• Risk factors can increase a person's risk, but they do not necessarily cause the disease.

• Some people with 1 or more risk factors never develop cancer. Other people can develop cancer and have no risk factors.

• Some risk factors are very well known. But there is ongoing research about risk factors for many types of cancer.

Some risk factors, such as family history, may not be in your control. But others may be things you can change. Knowing the risk factors can help you make choices that might lower your risk. For example, if an unhealthy diet is a risk factor, you may choose to eat healthy foods. If excess weight is a risk factor, your healthcare provider may check your weight or help you lose weight.

The best way you can protect yourself from anal cancer is to be aware of what makes you more likely to get it. Knowing more about the risk factors for anal cancer can help you make healthy choices to help you avoid it.

Who is at risk for anal cancer?

Human papillomavirus (HPV) infection

HPV infection causes almost all squamous cell anal cancers. It’s the strongest risk factor. HPV is spread through skin-to-skin contact during anal, oral, or vaginal sex. Not having anal sex is the best way to prevent anal HPV infection. Condoms can keep you from getting or giving HPV to your sexual partner, but they do not totally protect against the virus. That’s because this virus can be spread by skin contact from areas that are not covered by the condom. People may not even know they have the virus. You can have HPV for years without it causing symptoms.

A vaccine can greatly lower the risk for HPV infection. It’s important to know that the vaccine can only be used to prevent HPV. It does not help treat an existing infection. The vaccine may reduce your risk for anal cancer. But it only works if you get it before you are infected with HPV. You should get the vaccine before you become sexually active.

These factors may put you at higher risk for HPV infection. So they are also linked to higher risk for anal cancer:

• Multiple sex partners. If you have had many sex partners, you’re at higher risk of getting HPV and HIV. Both of these infections are linked to anal cancer. You also have a higher risk if your partner has had many sex partners.

• Anal sex. Having anal sex increases your risk for anal cancer. Because of this, men who have sex with men are at high risk.

• Weak immune system. You may have a weakened immune system from taking medicines after an organ transplant, or if you have HIV.

• Anal warts. Anal warts are caused by HPV. They are a sign that you have or had an HPV infection.

• A history of cervical, vaginal, or vulvar cancer. These cancers are also linked to HPV infection.

Smoking

Smokers are more likely to get anal cancer than nonsmokers. Quitting may reduce the risk for anal cancer and many other types of cancer.

Age

Most cases of anal cancer are found in people ages 50 to 80 years.

Repeated inflammation in the anal region

People who have chronic inflammation in the anus may have a higher risk for anal cancer. This inflammation can happen from fistulas, fissures, or perirectal abscesses.

What are your risk factors?

Talk with your healthcare provider about your risk factors for anal cancer and what you can do about them.