What`s new in anal cancer research and treatment?
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.
Improved understanding of the molecular changes inside anal cancer cells is expected to help scientists develop new drugs to fight this disease.
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 pre-cancer (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.
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.
New radiosensitizing agents -- chemotherapy and other drugs that increase the effect of radiation therapy -- are being studied in clinical trials. Combining these treatments might allow people to get lower doses of radiation and chemotherapy, which could lessen the possible side effects.
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.
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.
Studies are also looking at using imiquimod cream to treat anal intraepithelial neoplasia (AIN). Imiquimod is FDA approved as a treatment for anal and genital warts. It acts by boosting the body’s immune response. It has been used “off-label” to treat AIN in HIV positive men with good results, and more recently was shown to be helpful in a clinical trial. Imiquimod is a cream that is applied to the problem area 3 times a week to treat AIN.
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.
The HPV vaccines available at this time help prevent HPV infection, but do not treat infections already present. Researchers have also been working on vaccines to treat women and men who already have HPV infections, by causing their body’s immune system cells to attack the HPV-infected cells. Another goal of this research is to help the immune system attack pre-cancers and even cancers that contain HPV. An experimental vaccine has shown promise so far in treating pre-cancers of the vulva, but results for anal cancer or AIN are not yet available.
Last Medical Review: 01/02/2013
Last Revised: 01/02/2013