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Anus

The anus (or anal canal) is the tube that connects your rectum to the outside of your body. The anus controls the release of stool (poop) from your body. Cancer of the anus is also called anal cancer.

This information should not be used to diagnose yourself or in place of a doctor’s care.

Updated January 2021

Click here for a printable version of anal cancer information

Diagnosis & Staging

What are the signs and symptoms of anal cancer?

If you have early-stage anal cancer, you may not have any symptoms. 

Here are some symptoms of anal cancer:

  • Bleeding from your anus. This may be the first sign of cancer.

  • Having an itchy anus that does not go away.

  • Mucus coming out of your anus.

  • A change in your bowel movements ("going poop").
     
  • A sore on or near your anus.

  • Swollen lymph nodes in your groin or anal area.

If you have any signs or symptoms that you are worried about, please talk to your family doctor or nurse practitioner.

How is anal cancer diagnosed?

For more information on tests used to diagnose cancer, see our Recommended Websites - Screening and Diagnosis section. 

These are tests that may be used to diagnose anal cancer:

  • Physical examination: your doctor will examine you.  They will use their fingers to check your anus and rectum. This is called a digital rectal examination (DRE).
     
  • Anoscopy or sigmoidoscopy: A tube with a light is put into your anus to look inside the anal canal.

  • Biopsy of anal tissue: a small bit of tissue is removed and examined by a pathologist to see if it is cancer.
     
  • Gynecological exam: People with a vagina should have a gynecological exam with a pap smear to check for cervical cancer (cancer of the cervix).  Anal cancer and cervical cancer are both related to HPV (human papillomavirus).

  • If your lymph nodes are swollen, you may need other tests.

If any of these tests find anal cancer, you may need more tests to see if the cancer has spread.  You may need imaging tests like a CT scan, MRI or PET scan of the pelvis and abdomen area.

What are the types of anal cancer?

  • Squamous cell carcinoma: the most common type of anal cancer. 90% (90 out of 100) of anal cancers are squamous cell carcinomas. They start in the cells that line the anus.

  • Rare types of anal cancer include adenocarcinomas, basal cell carcinomas and melanomas. 

What are the stages of anal cancer?

Staging describes the cancer. Staging is based on how much cancer is in the body, where it was first diagnosed, if the cancer has spread and where it has spread to.

A lower number in each category usually means a better prognosis (how well your treatment will work and how long you will live). The stage of the cancer is used to plan your treatment. 

For more information on staging, see our About Cancer page.

Anal cancer staging:

  • Stage 0: Carcinoma in situ. This is early cancer and has not spread to any other areas.
     
  • Stage 1: Tumour is 2 cm or less.

  • Stage 2: Tumour is between 2 cm and 5 cm.

  • Stage 3: Tumour is more than 5 cm.

  • Stage 4: Tumour is any size and has spread to nearby organ(s) such as the vagina, urethra, or bladder

Treatment

What is the treatment for anal cancer?

Cancer treatment may be different for each person. It depends on your particular cancer. Your treatment may be different than what is listed here.

Surgery

  • A surgeon will take out the cancer if the tumour is small and there is no cancer in the sphincter (muscles that surround the opening of the anus and control the release of stool). 

Radiation Therapy and Systemic Therapy

  • If the tumour is small but there is cancer in the sphincter, you may get radiation therapy alone or with systemic therapy.

  • For large tumours, you will get systemic therapy and radiation therapy together. This gives a good chance of curing the cancer. However, side effects from this treatment are worse.
  • For the largest tumours, tumours that are not responding to other treatments, or cancers that come back after treatment, you may need your entire rectum removed. This means you will not be able to have a bowel movement (go poop). You will have a permanent colostomy (stool is collected in a pouch that is attached outside your body to your stomach area).

  • BC Cancer Radiation Therapy 
  • BC Cancer Systemic Therapy

What is the follow-up after treatment?

  • Follow-up testing is based on your type of cancer.

  • Guidelines for follow-up after treatment are on our website. These are guidelines written for your doctor, nurse practitioner or specialist. You can look at them to see what appointments and tests you might need after treatment.

  • After treatment, you will return to the care of your family doctor or specialist for regular follow-up. If you do not have a family doctor, please talk to your BC Cancer health care team.

  • Life after Cancer has information on issues that cancer survivors may face. 



More Information

What cause anal cancer and who gets it?

We do not know the cause of anal cancer.

Listed below are some of the known risk factors for this cancer. Not all of the risk factors below may cause this cancer, but they may help the cancer start growing.

  • Being over the age of 50.
  • Having an HPV (human papillomavirus) infection.
  • History of cervical, vulvar or vaginal cancer.
  • Anal sex.
  • Having many sexual partners.
  • Infection with HIV (human immunodeficiency virus).
  • Having Bowen's disease. This is a skin condition that causes rough, scaly patches of skin around the anus. If it is not treated, it can become cancer.
  • Smoking.

Anal cancer is not common.  There are about 600 cases each year in Canada. We do not have specific statistics on anal cancer. Anal cancer is included in "All Other Cancers" on our Statistics page

The number of women getting anal cancer each year is rising [See note below about Statistics].

Can I help prevent anal cancer?

  • Get regular sexual health screening. Sexual health screening is important for people who are sexually active.

  • Get vaccinated against HPV. It is best to get the HPV vaccine before becoming sexually active. However, people who are already sexually active may still benefit from the vaccine. There is more information on the Immunize BC website.

  • Practice safer sex by using a new condom every time you have vaginal, anal or oral sex. 

  • Stop smoking. Do not smoke and try not to be around tobacco and cigarette smoke. Even if you have been using tobacco for many years, quitting now will lower your risk of getting cancer. Support is available to help you quit smoking. Visit the BC Cancer Prevention page on Tobacco.

Is there screening for anal cancer?

  • Your anal canal should be checked once per year by a doctor or nurse practitioner. 
     
  • If you are at higher risk for anal cancer, you may need a test of cells scraped from your anus.

Where can I find more information?


NOTE:  Available statistics do not have information about the inclusion of transgender and gender diverse participants. It is unknown how these statistics apply to transgender and gender diverse people.  Patients are advised to speak with their primary care provider or specialists about their individual considerations and recommendations.

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