Anal Cancer

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Risk Factors


Anal cancer is cancer of the anus. This is the canal at the end of the large intestine, below the rectum. The anal sphincter is a muscular ring that controls and allows for bowel movements.

Treatment for anal cancer depends on how early it is detected, or if the cancer has spread.


Cancer occurs when cells in the body divide without control or order. Eventually these uncontrolled cells form a growth or tumor. The term cancer refers to malignant growths. These growths can invade nearby tissues and spread to other parts of the body.

There is evidence that human papillomavirus (HPV) infection is linked to many anal cancers. However, most people who have been infected with HPV do not get anal cancer.

Risk Factors

Factors that increase your risk of anal cancer include:

  • HPV infection
  • Receptive anal intercourse
  • Multiple sexual partners
  • HIV infection
  • Immunosuppressant drugs
  • Smoking
  • Cervical dysplasia or cervical cancer


Some anal cancers do not have symptoms. When symptoms do occur, they may include:

  • Anal bleeding with and without a bowel movement
  • Pain or pressure around the anus
  • Itching or discharge from the anus
  • A lump near the anus
  • Change in bowel habits
  • Thinning in the width of the stool


Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests can rule out or confirm a cancer diagnosis. Tests may include:

  • Digital rectal examination
  • Anoscopy—exam of the anus and lower rectum
  • Proctoscopy—exam of the rectum
  • Lab tests—focusing on the function of the bone marrow, kidneys, and liver
  • Biopsy

Imaging tests may be recommended to see inside your body structures. These may include:

  • Endoscopy—exam of the anal canal with a tube that has a camera on the end of it
  • Transrectal ultrasound
  • X-ray
  • CT scan
  • PET scan
  • Combined PET/CT scan
  • MRI


Talk with your doctor about the best treatment plan for you. Treatment options include the following:


In chemotherapy, drugs are used to kill cancer cells. Chemotherapy drugs travel through the bloodstream to kill cancer cells. Unfortunately, healthy cells and tissues are also damaged in the process. Chemotherapy is often combined with radiation therapy.

Radiation Therapy

Radiation therapy is often delivered at the same time as chemotherapy. Most anal cancers are treated with the combination of radiation therapy and chemotherapy. This treatment can avoid the need for surgery.

In some cases, radiation therapy alone may be used if chemotherapy is thought to result in too many side effects. In the treatment of anal cancer, radiation is delivered externally on a daily basis over 5-6 weeks.

Since radiation therapy damages healthy tissue as well as cancer cells, there are certain side effects associated with radiation therapy for the treatment of anal cancer. Scar tissue may form in the anus, keeping the anal sphincter from working properly. In addition, damage may occur that results in chronic rectal bleeding.


  • Local Resection
    Local resection allows for the removal of small cancers that have not spread to nearby lymph nodes or tissues. During this procedure, a small margin of healthy tissue around the cancers will also be removed. This surgery preserves anal function and the need for a permanent colostomy.
  • Abdominoperineal Resection (APR)
    An abdominoperineal resection (APR) is a surgery where the anus and rectum are removed by open surgery. This surgery is considered if the cancer cannot be treated or returns after chemotherapy and radiation.This surgery results in the formation of a permanent colostomy. A colostomy is a surgical opening through the wall of the abdomen into the colon. This is used as a path for waste material to leave the body. After a colostomy, you will wear a special bag to collect body waste.


You may be able to reduce your risk of anal cancer by reducing your exposure to HIV and HPV. There is a vaccine available, called Gardasil, that protects against four types of HPV.

This content was created using EBSCO’s Health Library. Edits to original content made by Swedish Medical Center. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.