A Guide to Anal Cancer

Medically Reviewed By Teresa Hagan Thomas PHD, BA, RN
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Anal cancer develops in the anus, which is the end of the long intestine, where stool exits the body. The first symptoms of anal cancer are usually bleeding from the anus and a lump in the area. Anal cancer is serious and rising in the United States. However, it is also treatable in many cases. Most cases of anal cancer are due to the human papillomavirus (HPV).

This article will explain more about anal cancer, what the symptoms are, what can cause it, and what the treatments are. 

What is anal cancer? 

Female's bottom in a black bathing suit on the beach
Alexey Kuzma/Stocksy United

Anal cancer starts in the cells of the anus. The anus is the end of the long intestine, which opens out through the body to pass stool. 

The anus contains sphincter muscles, which open and close to let the stool out. The muscles, along with the skin on the body, and the intestine, all make up the anus together. Anal cancer is a rare cancer type and occurs in less than 9,500 people per year in the U.S. 

Anal cancer primarily happens in older adults who are more than 60 years old. People under 35 years old do not often have it. According to the American Cancer Society, the risk of someone developing anal cancer is about 1 in 500

Stages of anal cancer

There are four different stages of anal cancer:

  • Stage 0: This is also called high-grade squamous intraepithelial lesion. In this stage, cells that can turn into cancer are in the innermost skin layer of the anus. 
  • Stage 1: In this stage, cancer is present, but any tumors are less than 2 centimeters in size. 
  • Stage 2: Stage 2 has two subtypes: 
    • IIA: This is a tumor between 2­–5 centimeters 
    • IIB: This is a tumor larger than 5 centimeters. 
  • Stage 3: Stage 3 anal cancer has three subtypes, IIA, IIB, and IIC. 
    • IIIA: In the lowest stage, the cancer is small and spreads to nearby lymph nodes. 
    • IIIB: In the next stage, the tumor is larger and spreads to nearby organs but not the lymph nodes. 
    • IIIC: In stage IIIC, the tumor spreads to nearby organs and lymph nodes.
  • Stage 4: Stage 4 cancer means that the tumors are any size and spread to organs and other distant parts of the body. 

Learn 15 things your oncologist wants you to know.

What are the types of anal cancer?

The most common type of anal cancer is squamous cell cancer, which makes up about 90% of anal cancers. This type of cancer begins in the lining of the anus. Squamous cell cancers are also called epidermoid cancers. 

Anal cancers can also be nonepidermoid cancers, which are rarer and include: 

  • Adenocarcinoma: This cancer begins in the mucus glands of the anus.
  • Basal cell carcinoma: This is a type of skin cancer.
  • Melanoma: This is another type of skin cancer that is a rare type of anal cancer.

What are the symptoms of anal cancer?

The symptoms of anal cancer include:

  • rectal or anal bleeding
  • lump on or near the anus
  • pain or pressure near the anus
  • itchiness near the anus
  • anal discharge
  • sudden change in bowel habits, such as having more bowel movements 
  • loose and runny bowel movements
  • difficulty controlling your bowel movements

If you have any of the symptoms of anal cancer, contact your doctor. A doctor can perform a physical exam, which will involve examining the anus, and performing other tests, like a biopsy, if needed. 

What are the causes of anal cancer?

The most common cause of anal cancer is HPV.

HPV is the most common sexually-transmitted infection in the U.S. 

Although HPV is the most common cause of anal cancer, the majority of people who have HPV will not develop anal cancer. Anal cancer is rare and often occurs in people who are more than 60 years old

What are the risk factors for anal cancer?

Although anal cancer is rare, the cases rise.

The risk factors for anal cancer include:

  • previously having cervical, vaginal, or vulvar cancers
  • previous experiences with an HPV infection and anal warts
  • history of an HIV infection
  • weakened immune system
  • experience smoking
  • anal sex without a condom or another barrier method

It is important to note that white females and Black males tend to experience anal cancer more often. However, the stress of enduring racism, discrimination, and racist systems may play a part in developing the disease beyond genetic factors.

How do doctors treat anal cancer?

Doctors primarily treat anal cancer in the following ways:

  • Surgery: This involves removing the cancer and, in some cases, changing the bowel opening to the abdomen. 
  • Radiation therapy: This treatment targets radiation directly to the cancer to kill the cells.
  • Chemotherapy: This is a medication that stops cancer cells from dividing.

In addition to the traditional treatments for anal cancer, there are also two new strategies that doctors are testing. These new treatments are radiosensitizer medications that can help improve the effectiveness of radiation, and immunotherapy, which helps activate the immune system to clear out cancer cells.

Can you prevent anal cancer?

Anal cancer is not always preventable. However, certain steps can help lower your risk of developing cancer, such as:

  • getting a vaccine against HPV
  • encouraging your sexual partners to get the HPV vaccine
  • using condoms or other barrier methods during sex
  • cleaning sex toys regularly
  • trying to quit smoking

Read about 10 foods that fight cancer.

What is the outlook for someone with anal cancer?

The 5-year relative survival rate for someone newly diagnosed with localized anal cancer is 82%. For all types of anal cancer combined, the 5-year relative survival rate is 65%. 

The exact outlook for someone with anal cancer will depend on many factors, such as:

  • age
  • health conditions
  • stage of cancer
  • treatment response to the cancer 

Relative survival rate

A relative survival rate gives an idea of how long someone with a specific condition may live after their diagnosis compared with someone without the condition. 

For example: A 5-year survival rate of 70% means that someone with that condition is 70% as likely to live for 5 years as someone without the condition. 

It is important to remember that these figures are estimates. Remember to talk with your doctor about your specific condition. 

Summary

Anal cancer is a rare type of cancer that occurs primarily in people who are more than 60 years old who have other risk factors. It is cancer in the tissues of the anus, which is the end of the large intestine where bowel movements pass out through the body.

The most common cause of anal cancer is an HPV infection. However, most people with HPV will not develop anal cancer.

With early detection, anal cancer is treatable. The 5-year relative survival rate for someone with localized anal cancer is 65%. 

The exact outlook for someone with anal cancer will depend on what other risk factors are present, what stage the cancer is, if it spreads to other parts of the body, and how the treatment responds to the cancer.

If you have any symptoms of anal cancer, such as a lump or bleeding near the anus, contact your doctor.

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Medical Reviewer: Teresa Hagan Thomas PHD, BA, RN
Last Review Date: 2022 Jun 21
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