What Is Anal Cancer?
Anal cancer is when cancer cells form within the tissues of
the anus. The anus is the opening at the bottom of the intestines where stools
come out of the body. Benign and malignant tumors in this area are signs of
anal cancer. Some non-cancerous forms of anal cancer can turn cancerous over
time. Anal cancer is rare and may be associated with the spread of cancer in
other body parts.
Types of Anal Cancer
There are various forms of anal cancer, which are defined by
the types of tumors that develop. Examples include:
- Benign tumors: Non-cancerous tumors in the anus,
they include polyps, skin tags, granular cell tumors, and condylomas.
- Pre-cancerous conditions: Benign tumors that may
become malignant over time, they are common with anal intraepithelial neoplasia
(AIN) and anal squamous intraepithelial neoplasia (ASIL).
- Bowen's disease: Also known as carcinoma in situ,
this condition is characterized by abnormal cells on anal surface tissue that
have not invaded deeper layers.
- Squamous cell carcinomas: These are malignant
tumors in the anus caused by squamous cells, which are cells that line most of
the anal canal. This is the most common type of anal cancer in the U.S. (American
Cancer Society, 2013).
- Basal cell carcinomas: A type of skin cancer
affecting areas of the skin exposed to the sun, this is a very rare form of anal
- Gastrointestinal stromal tumors: These are anal
cancers that are more likely to form in the stomach or small intestines.
What Causes Anal Cancer?
Anal cancer is caused by the development of abnormal cells
in the body. These cells can grow uncontrollably. As these abnormal cells
accumulate, they form masses known as tumors. Cancer cells can metastasize, or
spread through the body, and begin to infect nearby tissues.
Anal cancer is thought to be caused in part by the human papillomavirus (HPV). This is a
sexually transmitted disease. It is detected in the majority of anal cancer
Anal cancer may be the result of other cancers in the body
spreading through the anal canal.
What Are Risk Factors for Anal Cancer?
Like most cancers, anal cancer can occur in any person. Some
patients are more at risk of developing anal cancer than others. Risk factors
for anal cancer include:
- Human papillomavirus infection (HPV): HPV is
present in most cases of anal cancer. Having anal sex or more than five sexual
partners in a lifetime significantly increases the risk of anal HPV infections.
- Human immunodeficiency virus (HIV): HIV, the precursor
to AIDS, puts patients at a higher risk of anal cancer.
- Sexual activity: Promiscuity and receptive anal
intercourse can increase your risk of getting anal cancer. Not using condoms
may also put you at risk.
- Smoking: Smokers are much more likely to develop
cancer of the anus, even if they quit smoking.
- Weak immune systems: Weakened immune systems may
prevent the body from fighting off anal cancer. This is most common in patients
who take immune suppressants or who have had an organ transplant.
- Old age: Most cases of anal cancer occur in
patients over the age of 50 (Mayo Clinic, 2013).
What Are the Symptoms of Anal Cancer?
Anal cancer symptoms are similar to those of hemorrhoids,
irritable bowel syndrome, and many gastrointestinal diseases. They include
changes in bowel habits and bleeding from the rectum. Other symptoms are pain,
pressure, or the formation of a lump near the anus. Sometimes, patients may
experience discharge from the anus, or itching.
How Is Anal Cancer Diagnosed?
Anal cancer is often spotted early on as it develops in the
digestive track. Patients who experience bleeding, itching, or pain in the anus
often go to the doctor before anal cancer progresses past stage one. In other
cases, anal cancer is diagnosed during routine exams or procedures.
Digital rectal exams can detect some cases of anal
carcinoma. These are usually part of prostate exams for men. Manual rectal
exams are common for pelvic exams for both genders, where the doctor inserts his
or her finger into the anus to feel for lumps or growths.
Anal Pap smears can be used to test for anal cancer. This is
similar to a traditional Pap smear. The doctor will use a large cotton swab to
collect cells from the anal lining. These cells are then studied for
A doctor may biopsy a set of cells or tissues to test for
anal cancer if an abnormality is detected.
How Is Anal Cancer Treated?
There is currently no cure for anal cancer. Doctors
prescribe treatment for patients to reduce the spread of cancer cells and the
severity of symptoms. Some patients may go into remission with treatment. They
are still at risk of developing anal tumors at any time.
Anal cancer treatment is based on the stage of anal cancer a
patient has. Common treatments for anal cancer include:
Chemotherapy is a drug used to kill cancer cells and stop
them from growing. It can be injected into the body or taken by mouth. Pain
relievers may be used intermittently to control symptoms as well.
Local resection surgery is often used to remove a tumor in
the anus, along with some healthy tissue around it. It is most common with
patients whose cancer is in the lower part of the anus.
Abdominoperineal resection is a more invasive surgery. An incision
is made in the abdomen. The anus, rectum, and parts of the sigmoid colon are
Radiation therapies are common for many forms of cancer,
including cancer of the anus. X-rays and other radiations are used to kill
cancer cells in the body. This treatment is non-invasive and may be combined
with other cancer treatments.
What Is the Outlook for Anal Cancer?
There is currently no cure for anal cancer. However, many
patients are able to live long, healthy lives even after diagnosis. Early
detection is the key to sustained health.
According to the Surveillance Epidemiology and End Results
(SEER), the overall five-year survival rate for 2003-2009 was 65.6%. Patients
with localized anal cancer reported a 79.6% survival rate (SEER, 2013).
Preventing Anal Cancer
There is no guaranteed way to prevent anal cancer. But there
are some ways to potentially reduce your risk of anal cancer:
- Adjust your sexual habits. Limit the number of
sex partners you have. Use protection during intercourse. Avoid receptive anal
intercourse. Get tested regularly for sexually transmitted diseases.
- Stop smoking and avoid secondhand smoke.
If you have a high risk of anal cancer due to other factors,
such as your family history or age, get tested regularly to catch symptoms at
the first stage.