Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus.
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 and let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is about 1-1½ inches long.
Being infected with the human papillomavirus (HPV) increases the risk of developing anal cancer.
Risk factors include the following:
Signs of anal cancer include bleeding from the anus or rectum or a lump near the anus.
Tests that examine the rectum and anus are used to detect (find) and diagnose anal cancer.
The following tests and procedures may be used:
- Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Digital rectal examination (DRE): An exam of the anus and rectum. The doctor or nurse inserts alubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual.Enlarge
- Anoscopy: An exam of the anus and lower rectum using a short, lighted tube called an anoscope.
- Proctoscopy : An exam of the rectum using a short, lighted tube called a proctoscope.
- Endo-anal or endorectal ultrasound : A procedure in which an ultrasound transducer (probe) is inserted into the anus or rectum and used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called asonogram.
- Biopsy : The removal of cells or tissues so they can be viewed under a microscope by apathologist to check for signs of cancer. If an abnormal area is seen during the anoscopy, a biopsy may be done at that time.
Certain factors affect the prognosis (chance of recovery) and treatment options.
- The size of the tumor.
- Where the tumor is in the anus.
- Whether the cancer has spread to the lymph nodes.
The treatment options depend on the following: