What is anal cancer?
Anal cancer is the term for abnormal cell growth in the anal area or the anal canal. The anal canal connects the anus (the opening) to the rectum. This passage is about 1-2 inches long. It is the part of the body that excretes solid waste (bowel movements, feces). The disease also is called carcinoma of the anal canal.
The anus is the end of the digestive system. The anus is made up of tissue from the skin and from the intestine. While not the only type of anal cancer, the most common type is squamous cell carcinoma (SCC), a type of skin cancer.
How common is anal cancer?
The American Cancer Society has predicted that there will be about 8,300 new cases of anal cancer in 2019. Females will account for about 5,530 of these cases. The organization estimates deaths at 1,280, with women representing 760 of the total. The number of cases of anal cancer has been on the rise in the past several years.
Who does anal cancer affect?
The risk of anal cancer is higher in women than in men. The general risk of getting anal cancer is about 1 in 500-600 people.
What are the risk factors for anal cancer?
The term “risk factor” refers to a thing that makes it more likely that you will get a disease. For anal cancer, risk factors include:
- Human papilloma virus (HPV) infection. There are many types of HPV, which also causes genital warts. Some types of the virus are more likely to be linked with cancer of the anus, of the genitals, and certain head and neck cancers. Women who have cancer of the vulva, vagina or cervix have a higher risk of anal cancer.
- Being infected with the human immunodeficiency virus (HIV).
- Urogynecological HPV disease
- Engaging in anal sex as the receiving partner. This is true for both men and women. In general, having several partners for any type of sex increases the risk for getting HPV, HIV and anal cancer.
- Oral HPV disease.
- Getting older. The majority of anal cancer diagnoses are made in people who are 55 years old or older.
- Using tobacco.
- Having an impaired immune system due to disease or medication use. (For instance, people who are organ recipients must take medicine to prevent organ rejection.)
- Having an abnormal opening, called a fistula, which goes from the anus to the skin around the anus or occasionally to another place in the body.
Symptoms and Causes
What causes anal cancer?
It is believed that human papilloma virus (HPV) is a cause of anal cancer. However, having HPV does not mean you will definitely have anal cancer. This is true for the other risk factors as well: none of them mean that you will definitely develop anal cancer, but having them does increase the risk.
What are the symptoms of anal cancer?
About a quarter of the people who have anal cancer do not notice any symptoms. When present, symptoms may include:
Diagnosis and Tests
How is anal cancer diagnosed?
These tests are some of the tests used to diagnose anal cancer:
- Patient history: This includes questions about your medical history, lifestyle, symptoms and family medical history.
- Visual exam with anoscopy: Your healthcare provider will look at the area, possibly using an instrument called an anoscope. The anoscope is made up of a tube and a light and lets the provider see into the anal canal.
- Digital rectal exam (DRE): Your provider is also likely to do a digital rectal exam. The provider, wearing gloves, will put lubricant on a finger and put it inside the anus to feel for lumps or other problems.
- Anal Papanicolau (Pap) test
- Biopsy: This test removes a small bit of abnormal tissue for testing in a lab.
- Magnetic resonance imaging
Management and Treatment
What are the treatments for anal cancer?
As with most types of cancer, treating anal cancer depends on what type of cancer it is and how far it has spread past the point where it started. More so than with other cancers, the size of the cancer site is significant. In any case, your healthcare provider might provide you with information on participating in a clinical trial of treatment when it is appropriate.
Anal cancers in the early stage that have not entered the anal wall can be treated by removing the affected skin entirely. Even some smaller tumors (under one-half inch in size) that have grown into the anal wall can be removed surgically. These early stage and smaller tumors usually do not require further treatment with radiation or chemotherapy. This surgery is called local excision.
Radiation therapy uses equipment that focuses high-energy X-rays or particle streams at cancer cells in the body.
Chemotherapy uses drugs to kill cancer cells. Some chemotherapy can be taken by mouth, while other drugs must be given through the vein or as a shot into muscle.
There is a surgical treatment called abdominoperineal resection (APR). APR removes cancer cells in the anus, rectum and large intestine by cutting into the abdomen. APR might also remove lymph nodes which have become cancerous. APR is used when the cancer does not respond to other methods or if the cancer comes back. If you have APR, you will need to have a permanent colostomy. In this case, part of the colon is taken out and the remaining part opens into the stoma on the abdomen. The stoma is covered by a pouch so that stool may exit the body.
What are the complications or side effects of anal cancer treatment?
All treatments may have side effects. If you have any issues with side effects of any treatment, please be sure to talk to your healthcare provider. The provider will be able to help you find different ways of coping.
How can you prevent anal cancer?
There is no completely effective way to make sure you do not get anal cancer, but you can help protect yourself by reducing some risk factors.
Outlook / Prognosis
What is the prognosis / outlook for patients who have anal cancer?
The majority (up to 90 percent) of cases are cured by chemoradiation.
Your healthcare provider may recommend that you have follow-up visits every 3-6 months for 24 months after the chemoradiation is completed. It may also be recommended that you continue surveillance over the long-term, since some studies suggest that people with persistent or recurrent disease are treated more successfully when the cancer is found early.
When should you contact your healthcare provider with concerns about anal cancer?
You should contact your healthcare provider at any time if you find you have blood in your stools or changes in bowel movements that continue.
If you are treated for anal cancer, you should follow the appointment schedule set up by your healthcare provider and contact them as directed. For instance, your provider might tell you to call if you have pain or a fever.