What’s New in Anal Cancer Research?

Important research into anal cancer is now under way in many hospitals, medical centers, and other institutions around the world. Each year, scientists use clinical trials to find out more about what causes this disease, how to prevent it, and how to better treat it.

Looking at changes in anal cancer cells

We know that human papillomavirus (HPV) is a major cause of anal cancer. Researchers are now looking at how HPV affects molecules inside anal cells to cause them to become cancer. Improved understanding of the molecular changes inside anal cancer cells may lead to ways to prevent it and is also expected to help scientists find treatments using drugs that target these changes. Some clinical trials are studying drugs for this.

Screening for anal cancer

Ongoing research is being done on the value of screening tests for anal cancer, especially in people with major risk factors, such as HIV infection. (Screening is checking for a disease in people who don't have symptoms of it.) The test studied most is anal cytology, sometimes called the anal Pap test. This test may help find anal cancer when it's small, before it's causing symptoms and when it's easier to treat. Studies are also looking at whether the anal Pap test can help find anal pre-cancer (called anal intraepithelial neoplasia, or AIN), so it can be treated before cancer even develops. 

Treatment

Lasers

Better treatments for anal cancer with fewer side effects and long-term changes in body function are areas of active research. For instance, photodynamic therapy is being looked at to see if it can help treat pre-cancer changes.

Immunotherapy

Immunotherapy is treatment that boosts the body’s immune response against cancer cells. Pembrolizumab (Keytruda) and nivolumab (Opdivo) are immunotherapy drugs now being used in people with advanced anal cancer that has grown during at least one prior chemotherapy treatment. Different kinds of immunotherapy drugs are also being studied as an option for treating anal cancers that have not spread to distant organs but cannot be removed with surgery or that have not spread but are at high risk of coming back after chemoradiation and surgery. Another area of research is the combination of immunotherapy with chemotherapy.

Radiation therapy

Radiation therapy is a common treatment for anal cancer. Doctors are looking at ways to give external radiation including proton therapy more accurately and effectively to decrease the effects on normal healthy tissues. Other research is being done to learn about the possible benefits of combining chemotherapy with internal radiation therapy (brachytherapy) to treat anal cancer that has come back or gotten worse.

Combining lower doses of chemotherapy with radiation is another area of interest. Giving lower doses of chemo with radiation might help lessen side effects while still shrinking the cancer. Different drug combinations with radiation are being tested in clinical trials.

HPV vaccines

HPV vaccines are recommended for children and certain young adults to help prevent HPV infection that can cause some types of cancer, but the vaccines don't treat HPV infections that people already have. Doctors are looking at whether HPV vaccines might be used to help treat high-grade pre-cancers and keep them from becoming cancer especially in people with HIV. These vaccines may help the immune system attack pre-cancers and even cancers that contain HPV.