Important research into anal cancer is currently under way in many hospitals, medical centers, and other institutions around the country. Each year, scientists find out more about what causes the disease, how to prevent it, and how to improve treatment.

Causes and prevention

Research has identified the human papilloma virus (HPV) as a major factor in causing many cases of anal cancer. Researchers are learning how HPV affects molecules inside anal cells to cause them to become cancerous.

A vaccine to prevent infection with some types of HPV is now available. It was developed for use in women to reduce the risk of cervical cancers and precancers. The vaccine is also being looked at for use in young men. While it has not yet been studied, the hope is that the vaccine may eventually help prevent other cancers linked to HPV, including anal cancers.

Improved understanding of the molecular changes inside anal cancer cells is expected to help scientists develop new drugs to fight this disease.

HIV treatment

The immune deficiency of people with HIV infections can contribute to getting anal cancer. Although modern drug treatments for HIV can improve the immune response in those infected with the virus, this has not lowered the risk of anal cancer.

Early detection

Ongoing research is being done on the value of screening tests for anal cancer, especially in people with major risk factors. The test studied most is anal cytology, sometimes called the anal Pap test. This test may be useful in early diagnosis of anal cancer and precancer (called anal intraepithelial neoplasia (AIN). In this test, cells are gently scraped from the lining layer of the anus and checked under a microscope. Some doctors already recommend this test for people at high risk for anal cancers, such as those who are HIV positive.

Research is also in progress on treating AIN to help prevent cancer from developing.

Treatment

In the past several years, studies have shown the benefits of combining radiation with chemotherapy. This approach has reduced the number of surgeries needed for anal cancer, including the need for permanent colostomies.

Doctors are learning more about how to give external radiation more accurately and effectively and decrease the effects on normal healthy tissues. Other research is being done to learn about the possible benefits of combining external radiation and interstitial (internal) radiation therapy.

New drug combinations are being studied. For example, clinical trials have looked at the value of giving more chemo in stage III cancers.

New radiosensitizing agents -- chemotherapy and other drugs that increase the effect of radiation therapy -- are being studied in clinical trials. Combining these treatments may allow people to get lower doses of radiation and chemotherapy, which could lessen the possible side effects.

Some studies are looking at the use of newer targeted therapies to treat anal cancer. For example, doctors are trying to add the monoclonal antibody cetuximab (Erbitux), which is used in colorectal cancer, to see if it can help make chemotherapy work better.

Doctors are also studying ways to improve surgery and its side effects. For instance, studies are now looking at implanting an artificial bowel sphincter in people who have an extensive APR. The hope is that this artificial sphincter might allow people to avoid the need for a permanent colostomy. Currently such treatment is only available in carefully monitored trials.

Last Medical Review: 08/17/2009
Last Revised: 08/17/2009