(Cancer of Anus)
Definition
Definition
Anal cancer is cancer of the anus. This is the canal at the end of the large intestine, below the rectum. The anal sphincter is a muscular ring that controls and allows for bowel movements.
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Causes
Causes
Cancer occurs when cells in the body divide without control or order. Eventually, these uncontrolled cells form a growth or tumor. The term cancer refers to malignant growths. These growths can invade nearby tissues and spread to other parts of the body.
There is evidence that human papillomavirus (HPV) infection is linked to many anal cancers. However, most people who have been infected with HPV do not get anal cancer.
Risk Factors
Risk Factors
Factors that increase your risk of anal cancer include:
- HPV infection
- Receptive anal intercourse
- Multiple sexual partners
- HIV infection
- Use of immunosuppressant drugs
- Smoking
- Cervical dysplasia or cervical cancer
Symptoms
Symptoms
Some anal cancers do not have symptoms. When symptoms do occur, they may include:
- Anal bleeding with and without a bowel movement
- Pain or pressure around the anus
- Itching or discharge from the anus
- A lump near the anus
- Change in bowel habits
- Thinning in the width of the stool
Diagnosis
Diagnosis
You will be asked about your symptoms and medical history. A physical exam will be done. A digital rectal exam may also be done.
The rectum and anus may need to be examined. This can be done with:
- Anoscopy
- Proctoscopy
Your bodily fluids and tissues may be tested. This can be done with:
- Blood tests
- Biopsy
Images may be taken of your body structures. These may include:
Treatment
Treatment
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
Chemotherapy
In chemotherapy, drugs are used to kill cancer cells. Chemotherapy drugs travel through the bloodstream to kill cancer cells. Unfortunately, healthy cells and tissues are also damaged in the process. Chemotherapy is often combined with radiation therapy.
Radiation Therapy
Radiation therapy is often delivered at the same time as chemotherapy. Most anal cancers are treated with the combination of radiation therapy and chemotherapy. This treatment can avoid the need for surgery.
In some cases, radiation therapy alone may be used if chemotherapy is thought to result in too many side effects. In the treatment of anal cancer, radiation is delivered externally on a daily basis over 5-6 weeks.
Since radiation therapy damages healthy tissue as well as cancer cells, there are certain side effects associated with radiation therapy for the treatment of anal cancer. Scar tissue may form in the anus, keeping the anal sphincter from working properly. In addition, damage may occur that results in chronic rectal bleeding.
Surgery
Local Resection
Local resection allows for the removal of small cancers that have not spread to nearby lymph nodes or tissues. During this procedure, a small margin of healthy tissue around the cancers will also be removed. This surgery preserves anal function and the need for a permanent colostomy.
Abdominoperineal Resection (APR)
An abdominoperineal resection (APR) is a surgery where the anus and rectum are removed by open surgery. This surgery is considered if the cancer cannot be treated or returns after chemotherapy and radiation. This surgery results in the formation of a permanent colostomy. A colostomy is a surgical opening through the wall of the abdomen into the colon. This is used as a path for waste material to leave the body. After a colostomy, you will wear a special bag to collect body waste.
Prevention
Prevention
You may be able to reduce your risk of anal cancer by reducing your exposure to HIV and HPV. There is a vaccine available that protects against 4 types of HPV.
RESOURCES:
CANADIAN RESOURCES:
Public Health Agency of Canada http://www.phac-aspc.gc.ca
References:
http://www.cancer.org/acs/groups/cid/documents/webcontent/003083-pdf.pdf
Updated February 25, 2015. Accessed June 11, 2015.
Anal cancer. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed/what.php
Updated September 25, 2014. Accessed June 11, 2015.
Anal cancer. National Cancer Institute website. Available at:
http://www.cancer.gov/cancertopics/types/anal
Accessed June 11, 2015.
Joura EA, Leodolter S, Hernandez-Avila M, et al. Efficacy of a quadrivalent prophylactic human papillomavirus (types 6, 11, 16, and 18) L1 virus-like-particle vaccine against high-grade vulval and vaginal lesions: a combined analysis of three randomised clinical trials. Lancet. 2007; 369:1693.
Uronis HE, Bendell JC. Anal cancer: an overview. Oncologist. 2007;12:524-534.
Last Updated: 5/27/2014