Anal cancer is a rare type of cancer that affects the very end of the large bowel.

What causes anal cancer?

The exact cause of anal cancer is unknown, although a number of factors can increase the risk of developing the condition. These include:

  • infection with human papilloma virus (HPV) – a common and usually harmless group of viruses spread through sexual contact, which can affect the moist membranes lining your body
  • having anal sex with multiple sexual partners – possibly because this increases your risk of developing HPV
  • having a history of cervicalvaginal or vulval cancer
  • smoking
  • having a weakened immune system – for example, if affected by HIV

Increasing age increases the risk of anal cancer, with half of all cases diagnosed in people aged 65 or over. The condition is also slightly more common in women than men.

Symptoms of anal cancer

The symptoms of anal cancer are often similar to more common and less serious conditions affecting the anus, such as piles(haemorrhoids) and anal fissures (small tears or sores).

Symptoms of anal cancer can include:

  • rectal bleeding
  • itching and pain around the anus
  • small lumps around the anus
  • a discharge of mucus from the anus
  • loss of bowel control (bowel incontinence)

However, some people affected will be asymptomatic.

Diagnosing anal cancer

The medical practitioner will take a detailed history regarding the symptoms and also a thorough physical examination will be performed.

Abdominal examination as well as rectal examination will be done. A digital rectal examination is done by inserting a gloved finger into the anus so they can feel any abnormalities. Referral to a specialist may be necessary if recommended.

A number of different tests may be carried out to check for anal cancer and rule out other conditions.

Some of the tests you may have included:

  • sigmoidoscopy – where a thin, flexible tube with a small camera and light is inserted into the bottom to check for any abnormalities
  • proctoscopy – where the inside of the rectum is examined using a hollow tube-like instrument (proctoscope) with a light on the end
  • biopsy – where a small tissue sample is removed during a sigmoidoscopy or proctoscopy so it can be examined in a laboratory under a microscope

If these tests suggest the presence of anal cancer, the extent of spread will be assessed through scans. Once the tests are carried out, staging can then be done. This means giving it a score to describe how large it is and how far it has spread.


How anal cancer is treated

A multidisciplinary team will be present for better management. This is a team of different specialists who work together to provide the best treatment and care.

The main treatments used for anal cancer are:

  • chemoradiation – a combination of chemotherapy andradiotherapy
  • surgery – to remove a tumour or a larger section of bowel

In cases where the cancer has spread and can’t be cured, chemotherapy alone may be considered to help relieve symptoms. This is known as palliative care.

The main treatments are described in more detail below.


Chemoradiation is a treatment that combines chemotherapy (cancer-killing medication) and radiotherapy (where radiation is used to kill cancer cells). It’s currently the most effective treatment for anal cancer.

Chemotherapy for anal cancer is usually given in two cycles, each lasting four to five days, with a four-week gap between the cycles. In many cases, part of the chemotherapy is delivered through a small tube called a peripherally inserted central catheter (PICC) , which can stay in place until treatment has finished.

The tube means you don’t need to stay in hospital during each of the cycles of chemotherapy. However, you’ll be attached to a small plastic pump, which you take home with you..

Radiotherapy is usually given in short sessions, once a day from Monday to Friday, with breaks during weekends. This is usually carried out for five to six weeks. To prepare for radiotherapy, additional scans will be required.

Both chemotherapy and radiotherapy often cause significant side effects, including:

  • tiredness
  • sore skin around the anus
  • sore skin around the penis and scrotum in men or vulva in women
  • hair loss – limited hair loss from the head, but total loss from the pubic area
  • feeling sick
  • diarrhoea

These side effects are usually temporary, but there’s also a risk of longer-term problems, such as infertility. If you’re concerned about the potential side effects of treatment, you should discuss this with your care team before treatment begins.

Other possible long-term side effects can include:

  • bowel incontinence (or inability to hold feces from passing spontaneously)
  • long-term (chronic) diarrhoea
  • erectile dysfunction
  • vaginal pain during intercourse
  • dry and itchy skin around the groin and anus
  • bleeding from the anus, rectum, vagina or bladder


Surgery is a less common treatment option for anal cancer. It’s usually only considered if the tumour is small and can be easily removed, or if chemoradiation hasn’t worked.

A small and well-defined tumor may be removed though local excision which is done under general anesthesia.

If chemoradiation has been unsuccessful or the cancer recurs, a more complex operation called an abdominoperineal resection may be recommended. As with a local excision, this operation is carried out under general anaesthesia.

An abdominoperineal resection involves removing the anus, rectum, part of the colon, some surrounding muscle tissue, and sometimes some of the surrounding lymph nodes (small glands that form part of the immune system) to reduce the risk of the cancer returning.

During the operation, a permanent colostomy will also be formed to allow passage of stools. This is where a section of the large intestine is diverted through an opening made in the abdomen called a stoma. The stoma is attached to a special pouch that will collect stools after the operation.

Before and after the operation, a specialist nurse will be available who can offer support and advice to help adapt to life with a colostomy.  Adjusting to life with a colostomy can be challenging, but most people become accustomed to it over time.


At the end of the course of treatment, regular follow-up appointments are needed to monitor recovery and check for any signs of the cancer returning.

To start with, these appointments will be every few weeks or months, but they’ll gradually become less frequent over time.

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