Anal Cancer—Patient Version
The anus is part of the body’s digestive system and is the last part of the large intestine. Stool (solid waste) leaves the body through the anus.
The most common type of anal cancer is squamous cell carcinoma. Squamous cell carcinoma begins in flat cells lining the anal canal.
The number of cases of anal cancer diagnosed each year has been increasing over the last 10 years. Infection with human papillomavirus (HPV) is a major risk factor for anal cancer. Being vaccinated against HPV lowers the risk of anal cancer.