Types of anal cancer

There are different types of anal cancer. Knowing the type you have allows your doctor to plan your individual treatment.

Squamous cell carcinoma

Nearly all anal canal cancers (9 out of 10) develop in the squamous cells that line the anal canal and the anal margin. They are also known as keratinising squamous cell cancer.

Basaloid carcinoma

These are cancers that develop in the squamous cells in the transitional zone. They are also known as non-keratinising squamous cell cancer.

Adenocarcinoma

Some anal canal cancers develop in the glandular cells that produce mucus. They are rare – less than 5 in 100 (5%) anal cancers are this type. Anal adenocarcinomas behave very like rectal cancers and are treated in the same way. We have more information about treating rectal cancer.

Basal cell carcinoma

This is a type of skin cancer that develops in the area around the anus. It is usually treated in the same way as other basal cell skin cancers. We have more information about treating skin cancer.

Melanoma

This is a type of skin cancer that develops from cells called melanocytes. These are cells that give our skin its colour. Anal melanoma is rare – less than 1 in 100 (1%) anal cancers are this type. They are usually treated in the same way as other skin melanomas. We have more information about anal melanoma.

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The anus

The anus is the opening at the end of the large bowel. Stools pass through the anus when leaving the body.