Anal Cancer

Anal cancer is a rare form of cancer that develops in the tissues of the anus, which is the opening at the end of the rectum through which stool passes.

Anal cancer is an uncommon malignancy that starts in the anus-- the opening at the end of the rectum. According to the National Comprehensive Cancer Network there were 8200 newly diagnosed cases of anal cancer in 2017.

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.

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. 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.

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

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 other 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 CT scan and a pelvic MRI scan to assess for metastatic disease and to evaluate lymph node involvement.

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