Anal Cancer Facts
The American Cancer Society estimates that 6,230 people (3,980 women and 2,250 men) will be diagnosed with anal cancer in the United States in 2012. Anal cancer most often affects people between the ages of 50 and 80.
What Is Anal Cancer?
Anal cancer occurs when cells in the anus or the anal canal begin to grow abnormally. The anus is the opening to the outside of the body at the end of the large intestine below the rectum. The anal canal is the inch-and-a-half of tube inside the body that connects the rectum to the anus.
Several layers and types of cells make up the tissues in this area. So different types of cancer can develop here, depending on which layer of cells is affected.
Whatever the type of cancer, anal cancer cells do not respond to regular cell growth, division, and death signals like they are supposed to. They also don’t organize normally. Instead they grow into a tumor, which may break through surrounding layers of cells.
Most anal cancers are one of these two types.
- Squamous cell carcinoma—Cancer that starts in thin, flat cells (squamous cells) in the skin and linings of the body. It can start in the skin around the anus (perianal skin) and in the outer lining of the anal canal. This is the most common type of anal cancer.
- Adenocarcinoma—Cancer that starts in glands. Anal adenocarcinoma can start in cells that line the upper anal canal and in glands under the anal lining that make mucus.
Signs and Symptoms
Anal cancer may not cause any symptoms, or it may not cause symptoms until it’s advanced. Some symptoms of anal cancer are the same as symptoms of other problems, and they do not necessarily mean you have cancer. Be sure to talk to your doctor about any symptoms you are concerned about, especially the following:
- Bleeding, pain, or pressure in the anal area
- Itching, swelling, or a lump near the anus
- A change in bowel habits or diameter of the stool
- Discharge from the anus that’s not normal
- Swollen lymph nodes in the groin
If you have any of these, don’t delay. See your doctor to find out the reason. If you do have anal cancer, it’s more likely to be found early—when it’s easier to treat—if you see your doctor sooner rather than later about symptoms.
While there isn’t any known cause for anal cancer, several factors may contribute to its development, including infection with human papillomavirus (HPV).
To diagnose anal cancer, doctors have to remove a small sample of tissue from the anus and look at the cells under a microscope.
Staging is the process of determining how large your cancer is and whether it has spread to lymph nodes or other parts of the body. Doctors use stage to help guide treatment decisions.