December 2007

This information should not be used to self-diagnose, or be used in place of a qualified physician’s care.

Anus Cancer

• Anal cancers are treated by members of the BC Cancer Agency’s Gastrointestinal (GI) Tumour Group
• The anus or anal canal is the tube that connects the rectum to the outside of the body
• Anal cancer is not common. There are about 600 cases in Canada each year
• Incidence is rising for women
• Cancer of the anus can be cured in most cases

What causes it and who gets it?

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 be contributing factors.

• The cause of anal cancer is unknown
• The following contributing factors are recognised:
  • HPV (human papillomavirus) infections
  • Anal sex
  • Having many sexual partners
  • HIV (human immunodeficiency virus)
  • Bowen’s disease is a skin condition (a rough, scaly patch) that can occur in the skin around the anus. It can become cancer if left untreated
  • Smoking
• BC Statistics (2005)
  • 77 new cases diagnosed – 49 female, 28 male
  • 12 deaths – 9 female, 3 male
  • See graphs, or scroll to the bottom of the page.

Can I help to prevent it?

• Avoid anal sexual intercourse
• Use a condom, which can protect against HIV, but will not fully protect against HPV (human papilloma virus)
• Don’t smoke

Screening for this cancer

• No general screening program is effective for anal cancer
• If symptoms occur, physical examination by a doctor is effective for detecting anal cancer
• People at higher risk for anal surface cancers (intraepithelial neoplasia) may benefit from a test of cells scraped from the anus. These people include homosexual men, women who’ve had cervical or vulvar cancer, HIV-positive men and women and transplant recipients

Signs and Symptoms

• In the earlier stages, there may be no symptoms. The following symptoms must be assessed by your doctor:
• Bleeding from the anus often occurs and may be the first sign
• Persistent anal itching
• Discharge of mucus from the anus
• A change in bowel movements
• A sore that is on or near the anus
• Swollen lymph nodes in the groin or anal region

Diagnosis
Below is a list of some or all of the tests used to diagnose this type of cancer. We have more information on other diagnostic tests for cancer. 

• Physical examination
• Digital rectal examination (DRE)
• Anoscopy or proctoscopy, which is the insertion of a tube into the anus with a light to allow viewing of the interior of the anal canal
• Biopsy of anal tissue – a small bit of the suspicious tissue is removed and examined by a pathologist
• If swollen lymph nodes are present, it may be possible to test for the presence of cancer cells
• If cancer is found, further tests are done to determine the spread of the disease. These include a CT scan of the abdomen and pelvis, an ultrasound to examine the liver and an MRI to assess the pelvis

Types & Stages

Staging describes the extent of a cancer. The TNM classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.

• T describes the site and size of the main tumour (primary);
• N describes involvement of lymph nodes;
• M relates to whether the cancer has spread (presence or absence of distant metastases).

• Almost all anal cancers are squamous cell carcinomas, which start in the cells that line the anus
• The rest are cloacogenic (basaloid transitional)
• Adenocarcinomas are the rarest and develop in anal ducts and glands
• Very rarely, basal cell carcinomas and melanomas develop in the anus

Treatment

Cancer therapies can be highly individualized – your treatment may differ from what is described below.

• If the tumour is small and near the anus, surgery is used to remove it completely. The function of the anus and bowel should be retained
• If the tumour is larger or further into the anus, radiotherapy is used alone. It is expected to cure the cancer and retain the function of the bowel, but it does cause some side effects
• For larger anal cancers, a combination of chemotherapy and radiation therapy offers a good chance of curing the cancer. Side effects from this treatment are more severe. The treatment tries to maintain the patient’s ability to have normal bowel movements
• For the largest anal cancers, or those which do not respond to treatment, or if the cancer comes back after treatment, it may be necessary to remove the entire rectum and the patient will have a permanent colostomy

Follow-up after Treatment

• Guidelines for follow-up after treatment has ended have been developed by the BC Cancer Agency and are listed on our website
• You will be returned to the care of your family physician or a specialist, or a combination, and followup will happen regularly
• Followup testing is based on your type of cancer and your individual circumstances

Coping with Cancer

• BC Cancer Agency staff can help with quality of life issues for those living with or affected by cancer. This includes the physical, emotional, psychological and practical aspects of care. Each cancer experience is different, but in one way or another, many cancer patients share the same needs
• The effects of cancer and its treatment can present unique challenges: from practical concerns like money and housing, to emotional concerns like anxiety and grief. If you need support with the practical and emotional impacts of cancer, or in managing symptoms and side effects you can use the information in Coping with Cancer to connect to these resources

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Recommended websites

The following websites have been chosen and evaluated by the BC Cancer Agency.

1. NCI http://www.cancer.gov/
2. CCS http://www.cancer.ca/
3. ASCO http://cancer.net
4. BC Cancer Agency Recommended Websites – more cancer websites for anal cancer

Can I help with research at the BC Cancer Agency?

BC Cancer Agency patients are very helpful when it comes to the fight against cancer. Here are a few ways that you can help.

• Clinical Trials – Ask your oncologist if you qualify for a clinical trial.
  • What are the pros and cons of joining a clinical trial?
• Tumour Tissue Bank – support our research by donating some of your cancer tissue.
• BC Cancer Foundation – support our research with a donation of money.

Anal Cancer in British Columbia - graphs