Introduction
Anal cancer is an uncommon type of cancer. It results when cells in the anus grow abnormally and out of control. The anus is the opening at the end of the rectum through which waste products pass when you have a bowel movement. Treatment for anal cancer may include radiation, chemotherapy, surgery or a combination of treatments. Anal cancer that is diagnosed and treated early is associated with the best outcomes.
Anatomy
The first part of the colon absorbs water and nutrients from the waste products that come from the small intestine. As the colon absorbs water from the waste product, the product becomes more solid and forms a stool or feces. The large intestine moves the stool through the large intestine into the sigmoid colon, where it may be stored before traveling to the rectum. The rectum is the final 6-inch section of your large intestine which stores stool. No significant nutrient absorption occurs in the rectum or anal canal. From the rectum, the stool moves through the anal canal. It passes out of your body through your anus when you have a bowel movement.
Causes
Anal cancer occurs when the cells in the anus grow abnormally and out of control instead of dividing and replicating in an orderly manner. There are several different types of anal cancer cells. People that have the human papillomavirus (HPV), the sexually transmitted disease that causes genital warts, may have a higher risk if they have a version of the virus called HPV-16. People that have many sex partners, participate in anal sex, smoke, and have HIV, AIDS, or are immune compromised have a higher risk of developing anal cancer.
Anal cancer is fairly rare in the United States. It most frequently affects people at an average age of about 60 years old. Anal cancer is more common in women than men. Most people that are diagnosed and treated with anal cancer early may be cured. However, anal cancer is a serious condition and can cause death.
Symptoms
In some cases, anal cancer does not cause symptoms at all. In the majority of cases with symptoms, bleeding is one of the first signs. Anal cancer may also cause pain and lumps in the anal area. Your anal area may itch. You may have abnormal anal discharge. The diameter of your stools may change size. The lymph nodes in your anal and groin areas may be swollen.
Diagnosis
You should contact your doctor if you experience the symptoms of anal cancer. There are several other conditions with similar symptoms, and it is important to see your doctor to receive a diagnosis. Anal cancer that is detected and treated early is associated with the best outcomes. The American Cancer Society suggests that women receive a rectal examination as part of their annual exams, and that men receive an annual rectal exam after the age of 50. People at high risk for anal cancer may be tested at a younger age or more frequently.
Your doctor will review your medical history. It is important to tell your doctor about your risk factors and symptoms. Your doctor will conduct a rectal examination to detect abnormal masses or growths. Your doctor may use other evaluations to help diagnose your condition.
An endoscopy may be used to view the tissues inside of your anus. An anoscopy or a rigid proctosigmoidoscopy are types of endoscopies that may be used. An anoscopy involves placing an anoscope, a short thin tube with a light and viewing instrument, into the anus to allow your doctor to look for abnormalities. A rigid proctosigmoidoscopy is similar to an anoscope, but it is longer and allows your doctor to view more of the colon.
A biopsy may be obtained to test suspicious growths for cancer cells. There are several types of biopsy methods. Your doctor may use a fine needle aspiration to obtain cells or fluid through a fine needle. Your doctor may perform a sentinel lymph node biopsy if he or she suspects that your cancer has spread. A new method of sentinel lymph node biopsy uses an injection of a radioactive blue dye that highlights cancerous areas. A doctor will remove the blue stained areas and have biopsies performed on the cells.
Imaging tests may be used to show how far cancer has spread. Imaging tests may include ultrasound, computed tomography (CT) scans, chest X-rays, positron emission tomography (PET) scans, and magnetic resonance imaging (MRI) scans. These tests simply require that you remain motionless while the images are taken.
If you have anal cancer, your doctor will assign your cancer a classification stage based on the results of all of your tests. Staging describes the cancer and how it has metastasized. Staging is helpful for treatment planning and recovery prediction.
There is more than one type of staging system for cancer, and you should make sure that you and your doctor are referring to the same one. Generally, lower numbers in a classification system indicate a less serious cancer, and higher numbers indicate a more serious cancer. The stages may be subdivided into grades or classifications that use letters and numbers.
Treatment
The type of treatment that you receive for anal cancer may depend on several factors including the stage and type of the cancer that you have. The goals of treatment may be to cure the cancer, prevent the cancer from spreading, prevent the cancer from returning, and to relieve symptoms. Anal cancer may be treated with radiation therapy, chemotherapy, and surgery, or a combination of therapy types. It is common to receive at least two types of treatment.
Radiation therapy uses high-energy rays to destroy cancer cells and shrink tumors. It may be used before a surgery to shrink a tumor to make it easier to be removed. External radiation or internal radiation therapy may be used to treat anal cancer. External radiation delivers radiation from an external source, a machine. External radiation typically uses treatments 5 days per week for about 6 weeks. Internal radiation therapy, brachytherapy, involves implanting radioactive seed pellets in or near the cancer. The seeds deliver a slow dose of radiation. You may receive external radiation, internal radiation, or both.
Chemotherapy uses cancer fighting drugs or combinations of drugs to kill cancer cells. You may receive chemotherapy in the form of pills or they may be injected through a needle. Chemotherapy may be used in combination with radiation therapy or after surgery to destroy any remaining cancer cells.
There are several types of surgery for anal cancer. The type of surgery that you have may depend on several factors, including your general health, the size of your tumor, and the location of the tumor. A local resection is a procedure that is used to remove the cancer and the tissue around it. A local resection usually leaves the anus sphincter intact, and following surgery you will be able to have bowel movements.
An abdominoperineal resection (APR) may be used for cancer that has spread. This surgery involves removing the anus and part of the rectum. You will need a colostomy. A colostomy, a bag worn on the outside of the body to collect waste products, is necessary because you will not be able to have bowel movements following an APR. This surgery is not very common today because most people can be treated with a combination of radiation and chemotherapy.
Even with treatment, some cases of anal cancer may return. This is termed “recurrent anal cancer.” Your doctor can explain your risk for anal cancer and possible treatments if it does recur.
The experience of anal cancer and cancer treatments can be an emotional process for people with cancer and their loved ones. It is important that you receive support from a positive source. Some people find comfort in their family, friends, counselors, co-workers, and faith. Cancer support groups are another good option. They can be a source of information and support from people who understand what you are experiencing. Ask your doctor for cancer support group locations in your area.
Prevention
The American Cancer Society recommends anal cancer screening as part of a woman’s annual examination. Men should be screened for anal cancer every year when they reach the age of 50.
Lifestyle changes may help to prevent anal cancer. It can be helpful to quit smoking. If you have difficulty doing this yourself, ask your doctor for recommendations and resources that may help you.
If you do not have HPV, abstinence, not having sexual contact with another person, is the leading way to prevent HPV. Couples considering sexual relations should be tested for sexually transmitted diseases before beginning sexual contact. It is helpful to stay in a monogamous relationship with a person that you know has been tested and is HPV negative. A monogamous relationship means that you and your partner only have sexual contact with each other. If your partner has HPV, you may reduce the risk of transmission with condoms, but this is not a guarantee. You may prevent the spread of HPV and reduce your risk of anal cancer by not participating in anal sex.
Am I at Risk
Risk factors may increase your likelihood of developing anal cancer, although some people that develop anal cancer do not have any risk factors. People with all of the risk factors may never develop the disease; however, the chance of developing anal cancer increases with the more risk factors you have. You should tell your doctor about your risk factors and discuss your concerns.
Risk factors for anal cancer:
_____ People that have the HPV-16 subtype of the human papilloma virus (HPV), the sexually transmitted disease that causes genital warts, have an increased risk of developing anal cancer.
_____ Smoking increases the risk of anal cancer.
_____ People with multiple sex partners and those that participate in anal sex have an increased risk for anal cancer.
_____ People with HIV, AIDS, or a compromised immune system are at increased risk for anal cancer.
Complications
Anal cancer may spread to the lymph nodes or recur after treatment. Although most cases of anal cancer that are detected and treated early are curable, anal cancer is a serious condition that can result in death.