The anus is the end point of the large intestine, below the rectum, through where the stool (solid waste) leaves the body. The anus is formed partly by the outer layers of skin on the body and partly from the intestine. Two ring-shaped muscles, called sphincter muscles, open and close the anal opening to let the stool outside the body. The anal canal, the anus between the rectum and the anal opening, is about 1 ½ inches long.
The outer skin around the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer. Being infected with human papillomavirus (HPV) may influence the risk for anal cancer.
Among the risk factors there are: -Having over 50 years of age. -Being infected with human papillomavirus (HPV). -Having many sexual partners. -Having receptive anal intercourse (anal sex). - frequent anal redness, swelling and discomfort. -Having anal fistulas (abnormal openings). -Smoking cigarettes.
Among the signs that may indicate anal cancer there is bleeding from the anus or rectum or a lump near the anus. These and other symptoms could be due to anal cancer. Other conditions may cause the same symptoms. Call your doctor if you see any of the following problems: -Bleeding from the anus or rectum. -Pain or pressure in the area around the anus. -Itching or discharge from the anus. -A lump near the anus. -Changes in the habits of bowel function.
To detect (find) and diagnose anal cancer, tests are used to examine the rectum and anus. You can use the following tests and procedures: -Physical exam and history: An exam of the body to check general health status, including signs of illness such as lumps or anything else that does not seem normal. Also a history of the patient's health habits and their past illnesses and treatments.
-Digital rectal exam (DRE): examination of the anus and rectum. The doctor or nurse inserts a gloved lubricated finger in the lower rectum to feel for lumps or anything else that seems unusual.
-Anoscopy: examination of the anus and lower rectum using a short, lighted tube called anoscope.
-Proctoscopy: review of the rectum using a short, lighted tube called proctoscope.
-Anal or endorectal ultrasound: A procedure which introduces an ultrasound transducer (probe) in the anus or rectum and bounces high-energy sound waves (ultrasound) off internal organs and tissues to make echoes. The echoes form a picture of body tissues called a sonogram.
-Biopsy: The removal of cells or tissue for a pathologist to observe under a microscope to check for signs of cancer. If you notice an abnormal area during the anoscopy, you can perform a biopsy at that time.