What’s New in Anal Cancer Research and Treatment
Important research into anal cancer is currently underway in many university 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: Recent research has identified human papillomavirus (HPV) as a major factor in causing some types of anal cancer. It is beginning to show how HPV affects molecules inside anal cells to cause them to become cancerous.
Current research in this area includes development of vaccines to prevent HPV infection, thereby eliminating a cause of many anal cancers. Recently, a vaccine has been proven successful in preventing HPV 16 infection in women. The vaccine also prevents the development of precancerous changes in the cervix.
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 lead to developing anal cancer. Newer drug treatments for HIV will prevent the development of immune deficiency for many years.
Early detection: Ongoing research is studying the value of screening tests for anal cancer, especially in people with major risk factors. Some doctors feel that anal cancer is similar in some ways to cervical cancer. Anal cytology, a procedure similar to the Pap test for cervical cancer, may be useful in early diagnosis of anal cancer and even in finding precancerous changes called anal intraepithelial neoplasia (AIN). In this test, cells are gently scraped from the lining layer of the anus and checked under a microscope. Work is also in progress to find a way of treating this problem and preventing cancer from developing.
Treatment: In the past few years, for example, evidence has grown showing 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 treatment combinations are being studied. For example, clinical trials that compare 5-FU plus mitomycin with 5-FU and cisplatin may conclude that cisplatin is more effective than mitomycin.
New radiosensitizing agents, agents that increase the effect of radiation therapy, are being developed for use as combined modality therapy in chemotherapy and radiation therapy clinical trials. These studies offer new hope for patients to benefit from these therapies and to have acceptable toxicities.
Doctors are learning more about how to deliver external radiation more accurately and effectively and decrease the effect on normal healthy tissues. Other research is being done to learn about the possible benefits of using both external radiation and interstitial (implanted) radiation therapy.