Anal Cancer - What is Anal Cancer?

Anal cancer is an uncommon malignancy that starts in the anus -- the opening at the end of the rectum.

The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the outer, skin layers of the body and partly from the intestine. Two ring-like muscles, called sphincter muscles, open and close the anal opening to let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is about 1½ inches long. Cancer cells developing in this region is refer to as anal cancer.

The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer.

Approximately half of all anal cancers are diagnosed before the malignancy has spread beyond the primary site, whereas 13% to 25% are diagnosed after the cancer has spread to the lymph nodes, and 10% are diagnosed after the cancer has spread to distant organs, that is metastasized.

When it is found early, anal cancer is highly treatable.

The overall five-year survival rate following diagnosis of anal cancer is 60% for men and 71% for women.

When the cancer is diagnosed in its earliest stage, five-year survival rate is 82%. Once the cancer has spread to surrounding lymph nodes, the five-year survival drops to 60%. If the cancer has spread to distant organs, about one in five patients lives for five years or more.

Being infected with the human papillomavirus (HPV) can affect the risk of developing anal cancer.

Who is at risk? >>