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Types of anal cancer

The type of anal cancer you have depends on the type of cell the cancer started in. Most anal cancers start in the squamous cells. Find out about squamous cell cancers and other types. 

Squamous cell cancer

Squamous cell cancers are the most common type of anal cancer. Squamous cells carcinomas make up around 9 out of 10 (90%) of all anal cancers. They are also called epidermoid cancers.

This type of anal cancer starts in squamous cells which make up the lining of the anal canal and anal margin. 

There are 3 types of squamous cell cancer. Many anal cancers have a mix of all 3 cell types. Doctors treat all these squamous cell types of anal cancer in the same way.

But whether the cancer starts in the anal canal or anal margin can affect the type of treatment you have. 

Diagram showing the anatomy of the anus

Non epidermoid cancer

Non epidermoid cancers make up the rest of anal cancers. The treatment for non epidermoid cancer is different from the treatment for squamous cell anal cancer. 

There are different types of non epidermoid cancers, which are listed below. 

Adenocarcinoma 

This develops from the glandular cells that produce mucus in the anal canal. It is rare, and doctors treat it in the same way as rectal cancer.

Basal cell carcinoma

This is a type of skin cancer. It starts in the skin area around the anus.

Melanoma 

This is another type of skin cancer, it is very rare. It starts in skin cells called melanocytes. Doctors treat this type of anal cancer in the same way as melanomas.

Other types of non epidermoid cancer include:

  • small cell cancers
  • undifferentiated cancers
  • lymphoma's
Last reviewed: 
15 Apr 2019
  • Anal cancer:ESMO-ESSO-ESTRO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    R Glynne-Jones and others
    Annals of Oncology, 2015. Volume 25, Pages iii10-iii20

  • The differential diagnosis and interdisciplinary treatment of anal carcinoma
    D Raptis and others
    Dtsch Arztebl Int, 2015. Volume 3, Pages 243-249 

  • Textbook of uncommon cancer (5th ed)
    Raghavan and others
    Wiley and Sons, 2017

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