General Information About Anal Cancer

• 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.
• Most anal cancers are related to human papillomavirus (HPV) infection.
• 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 diagnose anal cancer.

Risk factors for anal cancer

• Being infected with human papillomavirus (HPV).
• Having a condition or disease that causes a weakened immune system, such as human immunodeficiency virus (HIV) or an organ transplant.
• Having a personal history of vulvar, vaginal, or cervical cancers.
• Having many sexual partners.
• Having receptive anal intercourse (anal sex).
• Smoking cigarettes.

Signs of anal cancer

• Bleeding from the anus or rectum.
• A lump near the anus.
• Pain or pressure in the area around the anus.
• Itching or discharge from the anus.
• A change in bowel habits.

Tests for Anal Cancer

• Physical exam and health history
• Digital rectal examination (DRE): An exam of the anus and rectum. The doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual.
• Anoscopy: An exam of the anus and lower rectum using a short, lighted tube called an anoscope.
• Proctoscopy: A procedure to look inside the rectum and anus to check for abnormal areas, using a proctoscope. A proctoscope is a thin, tube-like instrument with a light and a lens for viewing the inside of the rectum and anus.
• 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 pictures.
• Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body. The pictures are made by a computer linked to an x-ray machine.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body.
• PET scan (positron emission tomography scan): A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.

Anal Cancer Stages

Stage 0:

• Abnormal cells are found in the mucosa (innermost layer) of the anus. Stage 0 is also called high-grade squamous intraepithelial lesion (HSIL).

Stage I:

• Cancer has formed and the tumor is 2 centimeters or smaller.

Stage II:

• In stage IIA, the tumor is larger than 2 centimeters but not larger than 5 centimeters.
• In stage IIB, the tumor is larger than 5 centimeters.

Stage III:

• In stage IIIA, the tumor is 5 centimeters or smaller and has spread to lymph nodes near the anus or groin.
• In stage IIIB, the tumor is any size and has spread to nearby organs, such as the vagina, urethra, or bladder but not to lymph nodes
• In stage IIIC, the tumor is any size and may have spread to nearby organs and lymph nodes near the anus or groin.

Stage IV:

• In stage IV, the tumor is any size. Cancer may have spread to other parts of the body, such as the liver or lungs.