What you need to know about human papillomavirus (HPV) and anal cancer

Human papillomavirus (HPV) is a virus that is most easily passed during sexual contact. The body clears most HPV on its own. But certain types of the virus can cause a condition called anal dysplasia, which can then develop into anal cancer. Other types of HPV can cause other types of cancer. Some other types can cause warts of the genitals or anus (anogenital warts).

HPV cannot be cured by medication, but vaccines can prevent a person from getting some types of HPV, including the types that most often cause anal cancer. Consistent and correct condom use can reduce but not eliminate the risk of getting or passing on HPV during anal, vaginal or oral sex, and when sharing sex toys.

Early screening and treatment for anal dysplasia can help prevent anal cancer from developing. If anal cancer is caught and treated early, this can prevent the cancer from getting worse or spreading.

The words we use here – CATIE is committed to using language that is relevant to everyone. People use different terms to describe their bodies. This text uses medical terms, such as vagina and penis, to describe genitals. Other people may use other terms, such as private parts or dick or front hole. CATIE acknowledges and respects that people use words that they are most comfortable with.

What are human papillomavirus (HPV), anal dysplasia and anal cancer?

HPV is a virus that is most easily passed on during sex. There are many different types of HPV, and they can infect different parts of the body. Many people with HPV have no symptoms, so they don’t know they have it – but they can still pass HPV on to someone else.

Some types of HPV can cause cancers, including cancer of the anus and anal canal (anal cancer).

Anal cancer starts as a condition called anal dysplasia. Anal dysplasia happens when abnormal cells form areas of abnormal tissue called lesions.

Anal dysplasia usually doesn’t show symptoms, particularly in the early stages. Similarly, anal cancer often shows no clear symptoms until it is advanced and harder to treat. Symptoms of anal cancer can include:

• bleeding from the anus or blood in the stool (poo, shit)
• lumps around the anus or groin
• abnormal discharge
• changes in bowel habits (such as narrow stool, constipation or diarrhea)

Some of these symptoms are not specific to anal cancer, so they may be mistaken for other conditions.

Am I at risk of getting HPV, anal dysplasia or anal cancer?

Almost all cases of anal dysplasia and anal cancer are caused by HPV, so having HPV is the most important risk factor for these conditions.

Anyone who is sexually active, including people who experience sexual violence, can get HPV.

HPV is most easily passed on during condomless insertive sex. This includes anal sex and vaginal sex.

HPV can also be passed on through:

• oral sex (mouth on penis; mouth on vagina)
• oral-anal contact (rimming)
• sharing sex toys
• during a hand job or fingering
• through skin-to-skin contact of the genitals (even if no body fluids are present)

Engaging in condomless receptive anal sex (penis in anus) increases the risk of later developing anal cancer because it can result in an HPV infection of the anus or anal canal. 

For people who have one or more of the types of HPV that can cause anal cancer, factors like cigarette smoking and unhealthy diet can increase the chances of anal cancer developing.

Some groups of people carry a higher burden of anal cancer (it is more common). These include gay, bisexual and other men who have sex with men (gbMSM) as well as people who have had other HPV-related cancers, like cervical cancer.

HPV and HIV

People living with HIV have a higher risk of acquiring an HPV infection and of developing anal dysplasia. They also have higher rates of anal cancer. These rates are particularly high among gbMSM who are living with HIV. GbMSM living with HIV who also have a history of hepatitis B infection may be at still higher risk of developing anal cancer.

Effective HIV treatment greatly lowers the chances of developing HIV-related illnesses, including some cancers.

What can I do?

Reduce your chances of getting HPV infections

Get vaccinated against HPV to prevent future infections. HPV vaccines are widely available and highly effective.Talk to your healthcare provider about your options.

Use a condom during anal intercourse and vaginal intercourse.

Use a condom or oral dam during oral sex.

When sharing a sex toy, use a new condom and wash the toy between every use.

Get tested

If you experience any symptoms of anal cancer, speak with a healthcare provider right away. 

If you have risk factors for anal dysplasia or anal cancer, speak with your healthcare provider, even if you do not have any symptoms. They may suggest routine screening.

A healthcare provider can examine the anal canal using a gloved finger (digital exam) to check for cancerous bumps (tumours).

To check for anal dysplasia, a healthcare provider may examine the anal canal using a magnifying device with a light on it (anoscope). A small tissue sample (biopsy) may be taken, to determine if there are signs of dysplasia or cancer.

An anal Pap test may also be performed by inserting a swab into the anus and collecting cells to examine for changes that could lead to cancer.

Get treated

HPV cannot be cured from the body with medication.

Several treatments are used for anal dysplasia to remove or destroy lesions before they lead to cancer. Treatments include freezing (cryotherapy), laser treatment and surgery. Some of these treatments can be quite effective if the dysplasia is treated early. 

Treatments for anal cancer aim to remove cancerous tissue, slow the cancer’s growth and/or prevent it from spreading to other parts of the body. Treatment may involve surgery, radiation therapy, chemotherapy or combinations of these and other treatments. Treatments are most effective if the cancer is diagnosed and treated early.

Credits

This information sheet was developed in partnership with the Sex Information and Education Council of Canada (SIECCAN).

Resources

HPV, cervical dysplasia and cervical cancer – CATIE fact sheet
HPV, anal dysplasia and anal cancer – CATIE fact sheet