What Is Anal Cancer?
Cancer describes a set of diseases in which normal cells
in the body, through a series of genetic changes, lose the ability
to control their growth and to respect their neighbors. As cancers
grow, they invade the tissues around them (local invasion).
They may also spread to other locations in the body via the
blood vessels or lymphatic channels where they may implant and
grow (metastases). Tumors, or growths in the body, may be benign
or malignant (cancerous). When they are benign they may grow
but they do not spread to other locations. Malignant tumors
have the ability to invade deeply and to spread (metastasize).
Anal cancer arises from the cells around the anal opening (verge) or within the
anal canal (1-2 inches long) up to its junction with the rectum. Most anal cancers
arise from skin cells and are called squamous cell carcinomas. Some arise from the
special mucosal cells lining the upper anal canal and are called cloacogenic carcinomas.
Although several other types of cancer may occur in this area, these two are the
most common. They behave similarly and are treated in the same fashion. Cells that
are becoming malignant but have not invaded below the surface are "pre-cancerous" (carcinoma-in-situ).
This condition is called Bowen's disease.
How Common IS Anal Cancer?
Anal cancer is fairly uncommon. It accounts for about 1-2% of gastrointestinal
cancers. About 3,400 new cases of anal cancer are diagnosed each year in the U.S.A.,
and about 500 people will die of the disease each year. This may be compared to
140,000 new cases of colorectal cancer with 50,000 deaths per year.
Who Is At Risk?
We do not know the exact cause of most anal cancers. But we do know that certain
risk factors are linked to anal cancer. A risk factor is something that increases
a person's chance of getting a disease.
- Age - Most people with anal cancer are over 50 years old.
- Anal warts - Infection with the human papilloma virus
(HPV) which causes condyloma (warts) may increase the chance of
developing anal cancer.
- Anal sex - Persons who participate in anal sex are at an increased risk.
- Smoking - Harmful chemicals from smoking increase the risk of most cancers
including anal cancer.
- Immunosuppression - People with weakened immune systems, such as transplant
patients who must take drugs to suppress their immune systems and patients with HIV
(human immunodeficiency virus) infection, are at a somewhat higher risk.
- Chronic local inflammation - People with long-standing anal fistulas or
open wounds are at a slightly higher risk.
- Pelvic radiation - People who have had pelvic radiation therapy for rectal,
prostate, bladder or cervical cancer are at an increased risk.
Can Anal Cancer Be Prevented?
Few cancers can be totally prevented but your risk may be decreased
significantly by reducing your risk factors and by getting regular
checkups. Avoid anal sex and infection with HPV and HIV. Use condoms
whenever having any kind of intercourse. Although condoms do not
eliminate the risk of infection, they do reduce it. Stopping smoking
lowers the risk of many types of cancer, including anal cancer.
What Are The Symptoms Of Anal Cancer?
Many cases of anal cancer can be found early. Anal cancers form in a part of the
digestive tract that the doctor can see and reach easily. Anal cancers often cause
symptoms such as:
- Bleeding from the rectum or anus
- The feeling of a lump or mass at the anal opening
- Pain in the anal area
- Persistent or recurrent itching
- Change in bowel habits (having more or fewer bowel movements) or increased
straining during a bowel movement
- Narrowing of the stools
- Discharge (mucous or pus) from the anus
- Swollen lymph nodes (glands) in the anal or groin areas.
These symptoms can also be caused by less serious conditions such as hemorrhoids
but you should never assume this. If you have any of these symptoms, see your doctor.
How Is Anal Cancer Diagnosed?
Finding cancers early is the key to cure. Regular checkups with a digital (finger)
exam of the rectum and anus will find many problems which are easy to treat when
found early. Routine screening for colorectal and anal cancer in people without any
symptoms includes a digital rectal exam and test for blood in the stool yearly and
a flexible endoscopy exam (lighted probe) every 5-10 years starting at 50 years of
age.
If anal cancer is suspected based on your doctor's exam, a biopsy will be performed
to confirm the diagnosis. If the diagnosis of cancer is confirmed, additional tests
to determine the extent of the cancer may be recommended.
How Are Anal Cancers Treated?
Treatment for most cases of anal cancer is very effective. There are 3 basic types
of treatment used for anal cancer:
- surgery - an operation to remove the cancer
- radiation therapy - high-dose x-rays to kill cancer cells
- chemotherapy - giving drugs to kill cancer cells.
I including radiation therapy and chemotherapy is now considered the standard
treatment for most anal cancers. Occasionally a very small or early tumor may be
removed surgically (local excision), with minimal damage to the anal sphincter
muscles.
Will I Need A Colostomy?
The majority of patients treated for anal cancer will not need a colostomy. If
the tumor does not respond completely to combination therapy, if it recurs after
treatment, or if it is an unusual type, an abdomino-perineal resection (APR) removal
of the rectum and anus and creation of a colostomy may be necessary.
What Happens After Treatment For Anal Cancer?
Follow-up care to assess the results of treatment and to check for recurrence
is very important. Most anal carcinomas are effectively treated. In addition, many
tumors that recur may be successfully treated if they are caught early. A careful
examination by an experienced physician at regular intervals is the most important
method of follow-up. Additional studies may be recommended. You should report any
symptoms or problems to your doctor right away.
Conclusion
Anal cancers are unusual tumors arising from the skin or mucosa of the anal canal.
As with most cancers, early detection is associated with excellent survival. Most
tumors are well treated with combination chemotherapy and radiation. Recurrences
may often be treated successfully. Follow the recommended screening examinations
for anal and colorectal cancer and consult your doctor early when any anorectal
symptoms occur.
Reference: American Society of Colon
and Rectal Surgeons
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