Types of anal cancer
The type of anal cancer depends on the sort of cell the cancer starts in. Most anal cancers start in a type of cell called 
. Rarer types of anal cancer include and .
Squamous cell cancer
The anal canal and anal margin are lined with squamous cells. These protect the area and stop it from drying out.
Cancer that starts in squamous cells is called squamous cell cancer (SCC). This is the most common type of anal cancer making up more than 80 out of 100 (more than 80%) of all anal cancers. Squamous cell cancers are also called epidermoid cancers.
There are different types of squamous cell cancer. But doctors treat all types of squamous cell anal cancer in the same way.
Your treatment also depends on where the cancer is in your anus. Cancers that start in the anal canal might have different treatments to cancers that start in the anal margin.
Rarer types of anal cancer
There are other types of anal cancer that are very rare. The treatment of these cancers differs from the treatment for squamous cell anal cancer.
Adenocarcinoma
This starts in the cells that produce mucus in the anal canal. Doctors usually treat it in the same way as rectal cancer. This is normally a mixture of chemotherapy and radiotherapy (chemoradiotherapy) followed by surgery.
Treatment you have before surgery is called neoadjuvant treatment. The aim is to try and shrink the cancer to make it easier for your surgeon to remove it.
Basal cell carcinoma
This is a type of skin cancer. It starts in skin cells called basal cells. These are found in the deepest part of the outer layer of the skin (the epidermis). You might hear basal cell carcinoma called BCC. Anal BCC starts in the anal margin.
Treatment is normally surgery to remove the cancer and an area of healthy skin around it. Doctors call this a wide local excision (WLE).
Melanoma
Melanoma is a type of cancer that starts in cells called melanocytes. Melanocytes are found in the skin. They are also found in the layer of tissue lining some parts of your body, including the anus. Doctors call this lining the mucous membrane. Melanoma that starts in the mucous membrane is called mucosal melanoma. Anal melanoma is a type of mucosal melanoma.
Surgery is the main treatment for anal melanoma. If the melanoma hasn’t spread then you normally have a WLE.
Sometimes you might need a large operation to remove your anus, rectum and the last part of the large bowel (colon). This is called an abdominoperineal resection (APR). Your surgeon may recommend an APR if there is a chance the muscles in your anus won't work properly after a WLE.
If the cancer has spread, your doctor may recommend treatment with .
Other types of rare anal cancer
There are other rare types of anal cancer. These include:
- gastrointestinal stromal tumours (GIST) – a type of soft tissue
sarcoma neuroendocrine tumours lymphomas
