What is anal cancer?
Anal cancer is a cancer that affects the tissues of the anus. Most anal cancers are squamous cell carcinomas (SCC). Squamous cells are a type of cell that line the surface of the anal canal.
Some anal cancers are adenocarcinomas of the anus, a cancer of the cells that make the mucus that helps the stools (faeces) move smoothly out of the anus. In rarer cases, some SCCs affect the skin outside the anus (perianal skin cancers).
In 2016, 460 Australians were diagnosed with anal cancer. It is a rare cancer, more commonly diagnosed in people aged 50 to 60 years. Incidence of anal cancer has more than doubled in the last 20 years.
In 2018, 84 people died from anal cancer in Australia.
Anal cancer symptoms
The symptoms can include:
lumps around the anus or in the groin
ulcers around the anus
pain, discomfort, or itching around the anus
blood or mucus in stools (faeces) from the anus
difficulty controlling your bowel movements
a feeling of fullness, pain, or discomfort in the rectum.
These symptoms may be caused by other conditions such as haemorrhoids or tears in the anal canal. However, if symptoms persist, see your doctor for a check-up.
Causes of anal cancer
Some factors that can increase your risk of anal cancer include:
human papilloma virus (HPV) and other diseases including chlamydia, genital warts and AIDS/HIV
women who have already had cervical, vulval or vaginal cancer or a history of abnormal cells in the cervix, vulva or vagina
being a man who has sex with other men
people with weakened immune systems
Diagnosis of anal cancer
Tests to diagnose anal cancer may include:
You may have a blood test to see if your red blood cells are low (anaemia). You may also have blood tests to check your liver and kidney function.
The doctor will conduct a digital anorectal examination (DARE) by inserting a gloved finger into your anus to check for any swelling or lumps.
Your doctor will insert a small, rigid instrument called a proctoscope into your anus to see the lining of the anal canal and to take a tissue sample (biopsy) that will be sent to a laboratory for testing.
If anal cancer is detected, you may have scans to see if the cancer has spread to other parts of your body. These may include:
A magnetic resonance imaging (MRI) scan uses a powerful magnet and radio waves to create 3D pictures of areas inside the body. Sometimes dye will be injected into a vein to make the pictures clearer.
An ultrasound probe is inserted through the anus into your rectum. This can be uncomfortable but is usually not painful. The probe sends out soundwaves that echo when they meet something dense, like a tumour, and images are projected onto a computer screen.
A computerised tomography (CT) scan uses x-rays and a computer to create a detailed picture of an area inside the body. Before the scan, dye may be injected into a vein to make the pictures clearer.
This positron emission tomography (PET) scan involves a low-level injection of a radioactive drug, fluorodeoxyglucose (FDG). The FDG shows up areas of abnormal tissue.
Treatment for anal cancer
Anal cancer is rare so it is usually recommended that you be treated in a specialised centre by a multidisciplinary team.
Staging indicates the size of the cancer and how far it has spread and helps your doctors plan the best treatment.
Most people with anal cancer receive a combination of chemotherapy and radiation therapy (radiotherapy) treatments at the same time, called chemoradiation. Surgery may also be used. This will depend on the type and stage of anal cancer you have.
Radiation therapy (radiotherapy)
Radiotherapy, the use of x-rays to kill or injure cancer cells, is given either externally, where a machine directs radiation at the cancer and surrounding tissue; or from inside the body (brachytherapy), where radioactive material is put in thin tubes and placed near the cancer internally.
Radiotherapy to this area of the body may cause temporary or permanent infertility in both men and women. Therefore, if you are concerned about how treatment will affect your fertility, it is important to raise your concerns with your treatment team before treatment commences.
Chemotherapy can be used alone or combined with radiation therapy to treat anal cancer. Chemotherapy is usually given as a drug that is injected into a vein (intravenously).
For chemoradiation treatment, radiation therapy starts the same day as the first cycle of chemotherapy commences. Radiation therapy is delivered every week day for about five to six weeks. Side effects have been greatly reduced since the introduction a focused radiotherapy called intensity modulated RT (IMRT).
Surgery may be used to treat anal cancer if it is in the early stages, or hasn't completely gone after chemoradiation, or it comes back after treatment (recurs). The type of surgery will depend on the size and type of the cancer. An early stage tumour that doesn't affect the muscles around the anus may be operable as a local resection, where the affected area is removed.
A larger operation, called an abdomino-perineal resection, may be required if the cancer is present after initial treatment. This procedure involves the removal of the anus, rectum and part of the colon, and possibly lymph nodes near the anus and groin. If you have this procedure, you will have a permanent stoma (colostomy). Before and after your surgery, a stoma nurse will assist you in what is involved in living with a colostomy.
In some cases of anal cancer, your medical team may talk to you about palliative care. Palliative care aims to improve your quality of life by alleviating symptoms of cancer.
As well as slowing the spread of anal cancer, palliative treatment can relieve pain and help manage other symptoms. Treatment may include radiotherapy, chemotherapy or other drug therapies.
Treatment TeamDepending on your treatment, your treatment team may consist of a number of different health professionals, such as:
- GP (General Practitioner)- looks after your general health and works with your specialists to coordinate treatment.
- Radiation oncologist- prescribes and coordinates radiation therapy treatment.
- Medical oncologist- prescribes and coordinates the course of chemotherapy.
- Gynaecologist- specialises in treating diseases of the female reproductive system.
- Cancer nurses- assist with treatment and provide information and support throughout your treatment.
- Stoma nurses- provide information about surgery and can provide you with support to adjust to life with a temporary or permanent stoma.
- Sexual therapist- qualified counsellor who has been trained to help patients manage sexual concerns.
- Other allied health professionals- such as social workers, pharmacists and counsellors.
Screening for anal cancer
There is currently no national screening program for anal cancer available.
Preventing anal cancer
There are no proven measures to prevent anal cancer.
However, it is possible to reduce some of the risks, in particular HPV infection by using one of the HPV vaccines that are now available.
Prognosis for anal cancer
It is not possible for a doctor to predict the exact course of a disease, as it will depend on each person's individual circumstances. However, your doctor may give you a prognosis, the likely outcome of the disease, based on the type of anal cancer you have, the test results, the rate of tumour growth, as well as your age, fitness and medical history.
The most common types of anal cancer have a very good long-term prognosis, especially if the cancer is found early.
Understanding Anal Cancer, Cancer Council Australia © 2020. Last medical review of source booklet: July 2020.
Australian Institute of Health and Welfare. ACIM (Australian Cancer Incidence and Mortality) Books. Canberra: AIHW.
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