Anal Cancer

Anal cancer refers to cancer which develops in cells within the tissue of your anus and have the ability to multiply and spread.

Last modified: February 16, 2022

Quick facts about anal cancerQuick facts

  • Anal cancer is considered a rare cancer and accounts for less 500 new cancer cases diagnosed in Australia each year
  • Cases of anal cancer have increased over the past decade
  • 80% of anal cancer cases are caused by the human papillomavirus (HPV)

Types of anal cancerTypes of anal cancer

While most anal cancers are squamous cell cancers (SCC), they can also be classified as basal cell carcinoma (BCC), melanoma or adenocarcinoma of the anus.

Signs and symptoms of anal cancerSigns and symptoms

As signs and symptoms for anal cancer can be similar to other common conditions, it’s important to see your GP or healthcare professional if you experience any of the symptoms below. Discussing anything concerning with your doctor as soon as possible can help give you peace of mind and offer the best chance of successful treatment if you receive an anal cancer diagnosis.

Symptoms of anal cancer include:

  • Frequent urge to defecate

  • Difficulty controlling bowel movements

  • Blood or mucus in stool

  • Pain, discomfort or itching around the anus

Stages of anal cancerStages

The TNM system is used to stage anal cancer and helps doctors understand what your cancer looks like. The TNM stands for:

  • Tumour (T) – describes the size of the tumour and the extent the cancer has spread. The tumour can be graded from T1 (describing a tumour 5cm or less) to T2 (greater than 5cm).
  • Nodes (N) – describes whether the tumour has spread to nearby lymph nodes. Nodes can be graded from N0, where there has been no spread, through to N1, where the cancer has spread the lymph nodes.
  • Metastasis (M) – describes whether the cancer has spread to other areas of the body. Metastasis can be graded from M0, where there has been no spread through to M1, where the cancer has spread to other organs of the body and produced additional tumours.

The TNM information, along with other tests, helps determine the stage of your anal cancer using the guidelines below:

Stage I

The tumour is less than 2 cm in size

Stage IIA

The tumour is between 2 to 5 cm in size

Stage IIB

The tumour is larger than 5 cm in size and has not spread to any surrounding organs or lymph nodes

Stage IIIA

The tumour is no larger than 5 cm in size and has spread to surrounding lymph nodes

Stage IIIB

The tumour is any size and has spread to surrounding organs including the bladder, urethra or vagina, but not to the surrounding lymph nodes

Stage IIIC

The tumour is larger than 5 cm and has spread to surrounding lymph nodes but not to other body parts. Alternatively, the tumour is any size and has spread to surrounding organs and lymph nodes

Stage IV

The cancer has spread to distant organs of the body including the liver

Treatment for anal cancer

There are many different types of treatment for anal cancer. Your treatment will depend on you and your cancer.

Frequently asked questions about anal cancerFAQs

Is anal cancer hereditary?

Anal cancer is not considered to be genetic (passed on from a parent to a child).

What causes anal cancer?

Most cases of anal cancer are caused as a result of contracting human papillomavirus (HPV), a sexually transmitted disease. Factors which are known to increase the risk for development of anal cancers include your age, medical history, smoking habit and sexual activity.

What are the risk factors for anal cancer?

Risk factors that have been associated with developing anal cancer include:

  • Age – Anal cancer is more common in people aged over 50 years old
  • Medical history – Anal cancer tends to be more common in people who have other diseases or disorders, including HPV, HIV/AIDS, anal warts or autoimmune diseases such as lupus or Graves’ disease. In women, history of abnormal cervical screening tests or previous cases of cancer in the cervix, vulva or vagina increase your risk of developing anal cancer
  • Smoking – You may have an increased risk of developing anal cancer if you use tobacco
  • Sexual activity – Having a higher number of sexual partners increases your risk of developing sexually transmitted diseases, including HIV and HPV, which can lead to an increased chance of developing anal cancer. There is also a correlation between an increased risk of anal cancer and regular receptive anal sex
How common is anal cancer?

Anal cancer is considered a rare type of cancer. In Australia, less than 500 people are usually diagnosed with anal cancer each year.

How do you know if it’s anal cancer or haemorrhoids?

Haemorrhoids, or piles are soft lumps of enlarged blood vessels around and inside the anus. They usually result from a sudden increase in pressure – such as during pregnancy, constipation or heavy weightlifting.

Symptoms of haemorrhoids can include:

  • Painful bowel motions
  • Bright red blood on toilet tissue, or in the stool
  • Extreme itching around the anal area
  • A lump or swelling around the anus

Because the symptoms of haemorrhoids and anal cancer can be similar, it is extremely important that you see your GP or healthcare professional if you are experiencing any symptoms of haemorrhoids or anal cancer so that a diagnosis can be made.

How is anal cancer diagnosed?

Tests to diagnose anal cancer include:

  • Blood tests to check for red blood cell counts, as well as liver and kidney function
  • Examination and biopsy of the anal canal
  • MRI scan
  • Endorectal ultrasound
  • CT scan
  • FDG-PET scan
Where can I find out more about anal cancer screening?

There is no national screening program for anal cancer in Australia.

Are there clinical trials available for anal cancer that I can participate in?

Icon offers clinical trials across a wide range of cancer types and treatments. If you would like more information on participating in a clinical trial, please speak with your doctor who will be able to find a trial that might be right for you and your cancer.

See current clinical trials delivered by Icon Cancer Centre.


For a full list of references, click here.
  1. Mayo Foundation for Medical Education and Research. (2021, August 12). Anal cancer. Mayo Clinic. Retrieved January 13, 2022, from
  2. American Cancer Society. (2020, September 9). Risk factors for anal cancer. American Cancer Society. Retrieved January 13, 2022, from
  3. Cancer Council NSW. (2021, June 28). Anal cancer. Cancer Council NSW. Retrieved January 13, 2022, from
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