What is anal cancer?

Anal cancer is a cancer that starts in the anus — the area at the end of your digestive system.

It can grow in the:

• anal canal — the short tube just inside your anus
• lower rectum — the end part of the large intestine
• skin around your anus

Types of anal cancer

The most common type is squamous cell carcinoma. This starts in the cells that line the inside of the anal canal.

Other, less common types include:

• adenocarcinoma — a cancer that begins in gland cells
• neuroendocrine tumour — a cancer that begins in hormone-related cells
• lymphoma — a cancer of the immune system cells
• melanoma — a cancer that starts in pigment-producing cells
• verrucous carcinoma — a rare, slow-growing cancer

What are the symptoms of anal cancer?

Anal cancer can lead to symptoms that are similar to other common anal conditions, such as haemorrhoids or anal fissures.

Symptoms may include:

• a lump around the anus or inside the anal canal
• blood in the toilet or on toilet paper when you wipe after a poo
• anal pain, which may be constant or worse when you go to the toilet
• a feeling of fullness or a lump in the anal area
• a feeling like you need to poo even when your bowel is empty
• leaking fluid or mucus from your anus

These symptoms can start slowly.

Haemorrhoids are not a symptom of anal cancer.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes anal cancer?

Anal cancer is usually caused by human papillomavirus (HPV). This common virus spreads through sex.

Your chance increases if you're exposed to HPV more often or if your immune system can't clear the infection.

You may also have a higher chance if you:

• have anal sex or many sexual partners
• are a man who has sex with men
• live with HIV or a weakened immune system
• have or had anal or genital warts
• have had other HPV-related cancers such as cervical or vulvar cancer
• smoke

When should I see my doctor?

See your doctor if you notice any new changes around your anus. This is especially important if you are over 40 years of age.

Any lump or bleeding should always be checked by a doctor.

Because anal cancer can cause symptoms that look similar to other anal conditions, also see your doctor if:

• your symptoms don't get better
• your symptoms change
• you are worried about your symptoms

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is anal cancer diagnosed?

Anal cancer is diagnosed by checking your anus and the lower rectum. Your doctor will also ask about your symptoms and medical history.

Physical examination

Your doctor will look at the skin around your anus. They will also feel the lymph nodes in your groin.

They may do a digital rectal exam. This involves gently placing a gloved, lubricated finger into your anus to feel for any lumps or unusual areas.

Proctoscopy or sigmoidoscopy

If something unusual is found, your doctor may use a small device to look inside your anus and rectum, such as:

• proctoscopy (anoscopy) — a short tube used to see the anal canal
• rigid or flexible sigmoidoscopy — longer tubes that show the lower rectum

Biopsy

Your doctor may take a biopsy (a small sample of tissue). The sample is sent to a laboratory to check if there are cancer cells.

A biopsy is needed to confirm the diagnosis.

How is anal cancer treated?

Treatment for anal cancer depends on the type, size and stage of the cancer. It also depends on if it has spread to nearby lymph nodes.

Early anal cancer

If the cancer is small and on the skin around the anus, you may choose surgery called a local excision. This removes the cancer in one piece.

It is only offered when the cancer is small and can be fully removed.

Chemoradiotherapy

Most people have chemoradiotherapy, which combines:

• radiotherapy — uses targeted radiation to destroy cancer cells
• chemotherapy — uses medicines that help the radiation work better

It can take up to 6 months before the treatment has its full effect. During this time, your doctor will check how well the cancer is responding.

Surgery

Surgery (called abdominoperineal resection) is only recommended when:

• the cancer does not respond to chemoradiotherapy
• the cancer comes back after treatment

This surgery removes the anus and rectum and creates a permanent colostomy, where poo leaves the body through an opening in the tummy.

Read more about how to prepare for surgery.

Advanced cancer

If the cancer has spread and you have already tried other treatments, you may choose immunotherapy.

These medicines help your immune system attack cancer cells and may shrink the cancer or keep it stable for a period of time.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

Living with anal cancer

Living with anal cancer may affect your body, feelings and daily life. You can take steps to stay healthy and comfortable:

• Healthy lifestyle — try to be active, eat well and quit smoking.
• Emotional wellbeing — talk to a mental health professional or social worker. Support groups may also be useful.
• Relationships and sexual health — changes to your body, dryness or erection problems can affect sex and intimacy. Talk with your care team about aids or counselling.
• Managing side effects  — your care team can suggest ways to manage side effects.

Read more about anal care and living with a stoma.

What are the complications of anal cancer?

Anal cancer can cause problems when it grows or spreads. It can block the anal canal and make it hard to poo. It can also spread to nearby tissues, lymph nodes or other parts of the body.

Treatment can lead to side effects, such as:

• bowel problems — such as diarrhoea, rectal bleeding or trouble controlling your bowels
• tiredness
• skin changes around your anus or genitals
• temporary hair loss in the treatment area
• nausea and vomiting
• liver or urinary system changes
• changes to sexual or reproductive health — such as early menopause, fertility problems, vaginal dryness or erection problems

Can anal cancer be prevented?

You can lower your chance of anal cancer by protecting yourself from HPV and by checking for problems early.

You can help protect yourself from HPV by:

• practising safe sex
• limiting your number of sexual partners
• getting the HPV vaccine
• not smoking
• having regular screening tests, such as cervical screening and screening for anal cancer
• looking after your immune system if you are living with HIV

Screening for anal cancer

If you have a higher chance of anal cancer, your doctor may recommend regular screening. Screening can find early cell changes caused by HPV and you can have treatment before they turn into cancer.

Anal cancer screening may include:

• a digital rectal exam
• a swab test for high-risk HPV
• a cytology test, which checks the collected cells for any abnormalities
• high-resolution anoscopy — a small scope and light used to check the anal canal

Routine colonoscopy is not used to screen for anal cancer. It examines the bowel, not the anal canal.

If you're living with HIV, you should have regular screening for anal cancer. Screening usually starts at 35 or 45 years of age (depending on your sex and sexual practices), and it is repeated every 3 years if results are normal. You should also have a yearly doctor's exam to look for any changes.

Resources and support

• Cancer Council offers information about types of anal cancer and a guide for people affected by anal cancer.
• Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine has anal cancer screening guidelines.
• Continence Health Australia has information on improving bowel function after surgery.

Information for Aboriginal and/or Torres Strait Islander peoples

Our Mob and Cancer offers cancer information and support for Aboriginal and/or Torres Strait Islander peoples.

Languages other than English

Cancer Council has booklets, factsheets and videos in many community languages.

Information for LGBTIQ+ communities

Health Equity Matters has information about HIV and AIDS for HIV and LGBTIQ+ communities.

You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.