Anal Cancer

Diagnosis

Risk factors for anal cancer include:

• Age 50 or older
• Infection with the human papillomavirus (HPV)
• Frequent anal redness, swelling and soreness
• Anal fistulas (abnormal openings)
• Cigarette smoking

Mayo Clinic has one of the largest, most comprehensive cancer diagnosis and treatment programs in the world.

Mayo Clinic specialists use these tests and procedures to diagnose anal cancer:

• Colonoscopy or sigmoidoscopy — Colonoscopies and sigmoidoscopies are used to visually examine the anus and rectum for such abnormalities as polyps, cancer, ulcerations, pouches (diverticula) and narrowed areas (strictures). During the exam a colonoscope — a long, flexible tube about the thickness of a finger — is inserted into the rectum. A tiny video camera at its tip allows the doctor to view the inside of the colon.
• Biopsy — Biopsies may be necessary to confirm if there is cancer and determine the type. A biopsy is the removal and examination of a sample of tissue for study.

Physicians classify cancers of the anus into stages, according to the spread of the disease. Treatment may differ, depending on whether the cancer is limited to the anus or has spread. Staging can be done with these methods:

• Computed tomography (CT) scan — Computed tomography is an X-ray technique that produces more detailed images of internal organs than conventional X-rays. This procedure uses an X-ray tube that rotates around body and a large computer to create cross-sectional images (like slices) of the inside of the body. When images are combined, the doctor can clearly see tumors and accurately measure them. CT scans can pinpoint a tumor or infection deep in the body and are extremely effective in forming an accurate diagnosis. CT scans of the abdomen and pelvis may be performed to be certain the cancer has not spread to lymph nodes beyond the pelvic region or to the liver.
• Chest X-ray — A chest X-ray may be performed to determine that the cancer has not spread to the lungs.
• Endoanal ultrasound — A small, finger-sized ultrasound device is placed in the anus. Ultrasound (also called diagnostic medical sonography, sonography, and echocardiography) is an imaging method that uses high-frequency sound waves to produce precise images of structures within the body. Endoanal ultrasound can help if the lesion extends into the distal rectum.