Anal cancer is cancer that starts in the anus. The anus is the opening at the end of your rectum. The rectum is the last part of your large intestine where solid waste from food (stool) is stored. Stool leaves your body through the anus when you have a bowel movement.
Anal cancer is fairly rare. It spreads slowly and is easy to treat before it spreads.
Cancer - anus; Squamous cell carcinoma - anal; HPV - anal cancer
Anal cancer can start anywhere in the anus. Where it starts determines the kind of cancer it is.
The cause of anal cancer is unclear. However, there is a link between anal cancer and the human papillomavirus or HPV infection. HPV is a sexually transmitted virus that has been linked to other cancers as well.
Other major risk factors include:
Rectal bleeding, often minor, is one of the first signs of anal cancer. Often, a person mistakenly thinks the bleeding is caused by hemorrhoids.
Other early signs and symptoms include:
Treatment for anal cancer is based on:
In most cases, anal cancer that hasn't spread can be treated with radiation therapy and chemotherapy together. Radiation alone can treat the cancer. But the high dosage that's needed can cause tissue death and scar tissue. Using chemotherapy with radiation lowers the dose of radiation that's needed. This works just as well to treat the cancer with fewer side effects.
For very small tumors, surgery alone is typically used, instead of radiation and chemotherapy.
If cancer remains after the radiation and chemotherapy, surgery is often required. This may involve removing the anus, the rectum, and part of the colon. The new end of the large intestine will then be attached to an opening (stoma) in the abdomen. The procedure is called a colostomy. Stools moving through the intestine drain through the stoma into a bag attached to the abdomen.
Cancer affects how you feel about yourself and your life. You can ease the stress of illness by joining a cancer support group. Sharing with others who have common experiences and problems can help you feel less alone.
You can ask your provider or the staff at the cancer treatment center to refer you to a cancer support group.
Anal cancer spreads slowly. With early treatment, most people with anal cancer are cancer-free after 5 years.
You may have side effects from surgery, chemotherapy, or radiation therapy.
See your provider if you notice any of the possible symptoms of anal cancer, especially if you have any of the risk factors for it.
Since the cause of anal cancer is unknown, it's not possible to completely prevent it. But you can take steps to lower your risk.
Hallemeier CL, Haddock MG. Anal carcinoma. In: Tepper JE, Foote RL, Michalski JM, eds. Gunderson & Tepper's Clinical Radiation Oncology. 5th ed. Philadelphia, PA: Elsevier; 2021:chap 59.
National Cancer Institute website. Anal cancer treatment - health professional version. www.cancer.gov/types/anal/hp/anal-treatment-pdq. Updated January 22, 2020. Accessed October 19, 2020.
Shridhar R, Shibata D, Chan E, Thomas CR. Anal cancer: current standards in care and recent changes in practice. CA Cancer J Clin. 2015;65(2):139-162. PMID: 25582527 pubmed.ncbi.nlm.nih.gov/25582527/.