What Is Anal Cancer?

Anal cancer is an uncommon malignancy that starts in the anus -- the opening at the end of the rectum.

The American Cancer Society estimates that 7,210 cases of anal cancer will be diagnosed in 2014 and about 950 deaths will occur that year from anal cancer.

By contrast, some136,830 people are predicted to be diagnosed with colorectal cancer in the U.S. in 2014, and about 50,310 people are predicted to die of the disease that year.

Approximately half of all anal cancers are diagnosed before the malignancy has spread beyond the primary site, whereas 13% to 25% are diagnosed after the cancer has spread to the lymph nodes, and 10% are diagnosed after the cancer has spread to distant organs, or has metastasized.

When it is found early, anal cancer is highly treatable.

The overall five-year survival rate following diagnosis of anal cancer is 60% for men and 71% for women.

When the cancer is diagnosed in its earliest stage, five-year survival rate is 82%. Once the cancer has spread to surrounding lymph nodes, the five-year survival drops to 60%. If the cancer has spread to distant organs, about one in five patients lives for five years or more.

Who Gets Anal Cancer?

Most anal cancers (80%) are diagnosed in people who are over age 60. Prior to age 35, anal cancer is more common in men. However, after age 50, anal cancer is slightly more common in women.

The incidence rate of anal cancer is six times higher in single men as compared to married men.

Receptive anal intercourse is strongly related to the development of anal cancer.

Anal infection with human papillomavirus (HPV) resulting in genital warts is a major risk factor for the cancer.

Immunocompromised patients, such as those with HIV disease, are prone to get anal cancer. In this subgroup, the prognosis is worse, than for non-immunocompromised patients.

Gardasil, one of the HPV vaccines originally approved for the prevention of cervical cancer, is also approved for the prevention of anal cancer in men and women.


What Are the Symptoms of Anal Cancer?

The most common symptom associated with anal cancer is bleeding.

Because anal itching can also be a symptom of the cancer, many people initially attribute their bleeding and itching to hemorrhoids. This can delay the diagnosis of anal cancer.

Other signs and symptoms of anal cancer may include:

  • Pain or pressure in the anal area
  • Unusual discharges from the anus
  • Lump near the anus
  • Change in bowel habits

How Is Anal Cancer Diagnosed?

Anal cancer may be detected during a routine digital rectal exam or during a minor procedure, such as removal of what is believed to be a hemorrhoid.

The cancer may also be detected with more invasive procedures such as an anoscopy, proctoscopy, or endorectal ultrasound.

If cancer is suspected, a biopsy should be done and the specimen examined by a pathologist.

Staging workup should include an abdominal and pelvic CT scan or a pelvic MRI scan to assess the pelvic lymph nodes, a chest x-ray, and liver function studies. PET scanning is not necessary.

How Is Anal Cancer Treated?

Anal cancer is primarily treated with a combination of chemotherapy and radiation. This reduces the need for a colostomy and carries a 5-year survival rate of over 70%. The treatment of anal cancer, in this fashion, has not changed since 1974.

Surgery is reserved only for patients failing the above therapy. Salvage therapy has resulted in a 60% 5-year survival rate.

WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on September 15, 2015



News release, FDA.

American Cancer Society: "Detailed Guide: Anal Cancer."

American Cancer Society: "What is Anal Cancer."

National Cancer Institute: "Anal Cancer Treatment."

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