Anal cancer: symptoms and causes

Find out about anal cancer, including common symptoms and treatments.

What is anal cancer?

Anal cancer is a rare type of cancer that affects the anus.
The anus is where your bowel connects to the outside of your body (the bottom).
Anal cancer can start in any part of the anus.
It's usually caused by an infection called human papillomavirus (HPV).
Getting the HPV vaccine can help prevent anal cancer.
How serious anal cancer is depends on where it starts, how big it is, if it spreads and your general health.

Symptoms of anal cancer

Main symptoms of anal cancer

Symptoms of anal cancer can include:

bleeding from your bottom
itching and pain around your anus
small lumps around and inside your bottom
a discharge of mucus from your bottom
having problems controlling when you poo (bowel incontinence)
needing to poo often with looser, runnier poos

Anal cancer may have no symptoms at all, or they might be hard to spot.

Anal cancer symptoms are often similar to piles (haemorrhoids) and anal fissures, which are common and less serious conditions.

See a GP if:

you have symptoms of anal cancer
you notice a change around your anus that is not normal for you

Important

These symptoms are very common and can be caused by many different conditions.

Having them does not definitely mean you have anal cancer. But it's important to get them checked by a GP.

This is because if they're caused by cancer, finding it early means treatment is more likely to be successful.

What happens at the GP appointment

The GP will ask you some questions about your health and your symptoms.

They may feel your tummy and insert a gloved finger into your bottom to feel for lumps or anything wrong.

Referral to a specialist

You may get an urgent referral for more tests or to see a specialist in hospital if the GP thinks you have symptoms that could be cancer. This does not definitely mean you have cancer.

Causes of anal cancer

Main cause of anal cancer

Most anal cancers are caused by an infection called human papillomavirus (HPV).

You can get HPV from:

any skin-to-skin contact of the genital area
vaginal, anal or oral sex
sharing sex toys

Who is more likely to get anal cancer

Anal cancer is rare. Most people affected by HPV will not develop cancer.

You may be more likely to get anal cancer if you:

have anal sex
are over the age of 75
smoke
have had cervical, vaginal or vulval cancer
have a weakened immune system, such as from HIV or an organ transplant

How to reduce your risk of getting anal cancer

You cannot always prevent anal cancer. HPV vaccination is one of the best ways to protect against anal cancer.

All children aged 12 to 13 are offered the HPV vaccine. It helps protect against cancers caused by HPV, as well as genital warts.

The HPV vaccine is also recommended for other groups at higher risk of getting HPV, including:

men aged 45 years old and under who have sex with men
trans men and trans women aged 45 years old and under if their risk of getting HPV is the same as men who have sex with men
sex workers
people with HIV

There are also healthy changes you can make to lower your chances of getting anal cancer.

Do

use a condom when having sex to lower your chances of getting HPV
keep sex toys clean and do not share them
try to quit smoking

Get your symptoms checked

It's important to get any symptoms of anal cancer checked by a GP.

Anyone can get anal cancer, even if you do not think you have a higher chance of getting it.

Tests and next steps for anal cancer

Main tests for anal cancer

You might have some tests and scans to check for anal cancer if a GP refers you to a specialist.

The tests you have will depend on your symptoms.

The tests may include:

putting a thin tube with a camera and light into your bottom to check for any changes
taking a small sample from your anus (biopsy) so it can be looked at in a laboratory under a microscope
blood tests

Getting your results

You should get the results of your tests within a few weeks.

Try not to worry if your results are taking longer than you expected. You can call the hospital or GP if you're worried. They should be able to update you.

A specialist will explain what the results mean and what will happen next. You may want to bring someone with you for support.

If you're told you have anal cancer

Being told you have anal cancer can feel overwhelming. You may be feeling anxious about what will happen next.

It can help to bring someone with you to any appointments you have.

A group of specialists will look after you throughout your diagnosis, during and after treatment.

Your team will include a clinical nurse specialist who will be your main point of contact during and after treatment.

You can ask them any questions you have.

Macmillan Cancer Support has a free helpline that's open every day from 8am to 8pm.

They're there to listen if you have anything you want to talk about.

Next steps

If you've been told you have anal cancer, you may need some scans.

These, along with the tests you've already had, will help the specialists find out the size of the cancer and how far it has spread (called the stage).

The specialists will use the results of these tests and work with you to decide on the best treatment plan for you.

Treatment for anal cancer

Main treatments for anal cancer

Anal cancer is often treatable when found early.

The treatment you have for anal cancer will depend on:

the size of the cancer
where it is
if it has spread
your general health

The main treatment for anal cancer is a combination of radiotherapy and chemotherapy, called chemoradiation (or chemoradiotherapy).

Other treatments include chemotherapy or radiotherapy on their own, and surgery.

The specialist care team looking after you will:

explain the treatments, benefits and side effects
work with you to create a treatment plan that is best for you
help you manage any side effects, including any changes to your diet

You'll have regular check-ups during and after any treatments. You may also have tests and scans.

If you have any symptoms or side effects that you are worried about, talk to your specialists. You do not need to wait for your next check-up.

Chemotherapy and radiotherapy

To treat anal cancer, chemotherapy and radiotherapy are often used together. This is called chemoradiation or chemoradiotherapy.

Radiotherapy uses high-energy radiation to kill cancer cells.

Chemotherapy is medicine taken to kill cancer cells.

Chemoradiation is usually given if anal cancer has not spread. It means most people with anal cancer do not need to have surgery.

Surgery

Surgery is sometimes used to treat anal cancer.

You may have surgery if:

the cancer is small and has not spread
chemoradiation does not get rid of all the cancer, or it comes back
you are not able to have radiotherapy, for example if you've had radiotherapy in the pelvic area before

Surgery for anal cancer usually involves removing just the part of the anus that's affected.

If the cancer has spread or come back, you may need surgery to remove all of the anus, the rectum (which joins the anus to the bowel) and part of the bowel.

This means you'll need to have a pouch (stoma bag) fitted to the outside of your body to collect poo. This is called a colostomy.

If you need a colostomy, you'll be looked after by a specialist stoma nurse. They'll be able to offer you support.

Care after your treatment

The clinical nurse specialist, or another member of your specialist team, will be able to give you information on follow-up care after treatment.

It may also help to get support from family, friends or a support organisation, if you get anxious before or between appointments.