anal cancer: do you know the signs?

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while there is no way to prevent anal cancer, you can reduce your risk by getting vaccinated against hpv, practicing safe sex and quitting smoking.

by dave yasvinski

published feb 13, 2023

last updated feb 19, 2025

3 minute read

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3 minute read

join the conversation

hpv is a top risk factor when it comes to anal cancer

two-thirds of people who are diagnosed with anal cancer will live at least five years. getty

anal cancer is a form of disease that occurs when the cells in the anus (or anal canal) become cancerous and stop behaving normally. the anus is a short tube located at the end of the large intestine (after the rectum) and the part of the digestive system where stool exits the body. although this form of cancer is rare, once the cells in the anus or anal area turn cancerous, they can form tumours that invade and destroy surrounding tissue.

according to the canadian cancer society, infection by the human papillomavirus (hpv) is the most important risk factor for anal cancer as it is present in the vast majority of cases. the sexually transmitted disease is believed to be the most common cause of anal cancer. other risk factors for the disease include a history of cancer, use of drugs that impair the immune system, older age, smoking, having multiple sex partners and engaging in receptive anal sex.

although anal cancer does not often spread to other areas of the body, when it does — most commonly to the liver and lungs — it can be particularly difficult to treat. a combination of chemotherapy and radiation therapy has proven effective against the disease, often removing the need for surgical intervention.

symptoms of anal cancer

anal cancer starts out small and can be difficult to detect until tumours begin to grow into surrounding tissue. the most common (and usually first) symptom of the disease is small amounts of bleeding from the anus. other symptoms, when they appear, can include:

anal itching
pain or discomfort in the anal area
a mucus discharge from the anus
change in bowel habits or a narrowing of the stool
swollen lymph nodes in the groin or anal area

diagnosing anal cancer

doctors will usually ask about symptoms and family history when investigating a potential case of anal cancer. they will also likely perform a physical inspection, including a digital rectal exam. this procedure, which men often receive as part of a prostate exam, involves the doctor inserting a gloved, lubricated finger inside the rectum in search of growths or other abnormalities. other tests, according to the mayo clinic, can include:

a visual inspection using an anoscope. a short tool with a light is inserted into the anal canal and rectum in search of abnormalities
imaging tests. a transrectal ultrasound of the anal canal can give doctors a better look at the area of concern. a pet-ct scan, mri or chest x-ray can determine if the cancer has spread to other areas of the body
biopsy. a small sample of anal tissue may be removed for closer examination under a microscope

chemotherapy drugs, which are injected or taken orally, seek out and kill any rapidly growing cells. getty

treating anal cancer

addressing this disease depends on a number of factors, including the size and location of the tumour and a patient’s overall health. doctors generally use a combination of chemotherapy and radiation therapy to treat this disease as the two forms of treatment enhance one another and improve the overall chances of eradication.

chemotherapy drugs, which are injected or taken orally, seek out and kill any rapidly growing cells. this means they may inadvertently attack healthy cells that also grow rapidly, including those found in the gastrointestinal tract and hair follicles. this can lead to nausea and hair loss over the course of treatment.

radiation therapy kills cancer cells with high-powered beams, such as x-rays. unfortunately, this may also kill healthy cells in the area and result in sores and irritated skin around the anus. surgery may also be used to remove early stage anal cancers or those that do not respond to chemotherapy or radiation treatment.

preventing anal cancer

while there is no way to prevent anal cancer, you may be able to reduce your risk of the disease by getting vaccinated against hpv, practicing safe sex and quitting smoking.

prevalence of anal cancer

in canada, the five-year net survival (or probability of surviving in the absence of other causes of death) for anal cancer is 66 per cent. this means that, on average, two-thirds of people who are diagnosed with the disease will live at least five years.

support and resources for anal cancer

the canadian cancer society offers more information about anal cancer, and any other form of cancer that affects you or someone you know. the ccs also has a cancer information hotline and a community service locator to help you find support in your area.

dave yasvinski is a toronto-based writer.

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