Types of Anal Cancer
There are different type of cancers that can develop in different parts of the anus.
Types of anal cancer include:
- Squamous Cell Carcinomas
The most common type of anal cancer (about 75% of cases) is squamous cell carcinoma, which starts in the cells lining the anal margin and the anal canal.
The anal margin is the edge of the anus that can be partly seen as darker skin on the outside of the body and the anal canal is the part of the anus that is inside the body.
The earliest form of squamous cell carcinoma is known as carcinoma in situ.
- Adenocarcinomas
An estimated 15% of anal cancers are called adenocarcinomas.
These affect glands in the anal area and one type of adenocarcinoma that can occur in the anal area, known as Paget’s disease, can also affect the vulva, breasts, and other areas of the body. Anal adenocarcinomas are usually treated in the same way as rectal cancer.
- Skin cancers
A small number of anal cancers are either basal cell carcinomas, or malignant melanomas – two different types of skin cancer.
- Other types of anal cancer
Other, very rare types of anal cancer are lymphomas, and gastrointestinal stromal tumours (GIST).