Anal cancer is a rare type of cancer that can cause symptoms such as anal itching or burning, pain in the anus (especially during bowel movements), and bright red blood in the stool. It can also lead to swelling around the anus and a noticeable lump or mass.
Anal cancer is more common in people over age 50. It may also be more likely in people who have HPV or HIV, those with an immunosuppressive condition, or those who practice anal sex.
It is important to see a colorectal surgeon or gastroenterologist if symptoms suggest anal cancer. Testing can help confirm the diagnosis and guide the most appropriate treatment.
Common symptoms
The main symptoms of anal cancer are:
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Anal pain during bowel movements;
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Swelling in the anal area;
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Changes in bowel habits;
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Anal itching or burning in the anus;
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A mass or lump in the anus;
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Enlarged lymph nodes.
If symptoms suggest anal cancer, a person should see a primary care provider or a proctologist so tests can be done and a diagnosis can be made.
Confirming a diagnosis
Anal cancer is diagnosed based on symptoms and tests that may be recommended by a healthcare provider, such as a digital rectal exam, proctoscopy, and anoscopy. These tests can be painful because of the lesion caused by the cancer and may be done with anesthesia.
These tests are important because they allow the provider to examine the anal area and look for changes that may suggest disease.
If an abnormal finding suggests cancer, a biopsy may be ordered to determine whether the change is benign or malignant. If the biopsy indicates anal cancer, the provider may also recommend a magnetic resonance imaging (MRI) scan to evaluate how far the cancer has spread.
Risk factors
Anal cancer is more likely to occur in:
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People infected with HPV or HIV;
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People with a history of cancer;
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People who use medications that reduce immune system activity;
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People who practice anal sex;
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Smokers;
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People with an anal fistula.
According to the Centers for Disease Control and Prevention (CDC), HPV is thought to be responsible for more than 90% of anal cancers. Anal cancer is also more common in people who have had an organ transplant and in those over age 50.
Main stages
Based on tumor development, anal cancer can be classified into four main stages:
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Stage 1: the tumor is smaller than 2 cm;
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Stage 2: the tumor is 2 cm to 4 cm and located only in the anal canal;
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Stage 3: the tumor is larger than 4 cm and has spread to nearby areas, such as the bladder or urethra;
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Stage 4: the cancer has metastasized to other parts of the body.
Once the stage is identified, an oncologist or colorectal surgeon can recommend the best treatment to improve the chance of cure. In most cases, chemotherapy and radiation therapy are needed.
Treatment options
Treatment for anal cancer is usually coordinated by an oncologist and a specialized surgeon, such as a colorectal or surgical oncologist.
The standard approach, based on National Cancer Institute (NCI) guidelines, involves combined chemotherapy and radiation therapy over five to six weeks, typically without the need for hospitalization. In most cases, this combination can cure the cancer, making surgery unnecessary.
Surgery may be recommended to remove small anal tumors, especially in the first two stages of anal cancer. In more severe cases, surgery may be needed to remove the anal canal, rectum, and part of the colon.
In the most severe cases, when a large portion of the intestine must be removed, an ostomy may be needed. An ostomy is a pouch attached to the abdomen that collects stool that would normally pass through the anus, and it should be changed whenever it becomes full.