HIV- positive anal cancer: an update for the clinician

Anal cancer used to be a rare cancer traditionally associated with elderly women. There are approximately 5260 cases per year in the U.S. (1). The onslaught of the Human Immunodeficiency Virus (HIV) virus has led to a change in anal cancer demographics. Anal cancer is on the rise in the U.S and the number of anal cases documented has quadrupled in the past 20 yrs correlating with the rise of the HIV epidemic. The incidence of anal cancer is 40 to 80 fold higher in the HIV positive (HIV+) population when compared to the general population (2). With the advent of highly active antiretroviral therapy (HAART), HIV+ patients are living longer as less are progressing to AIDS. As a consequence non AIDS defining cancers such as anal cancer are on the rise. Factors implicated in the etiology of anal cancer in HIV+ patients include (Human papillomavirus) HPV virus status, sexual habits, and a history of smoking. HPV 16 and receptive anal intercourse (RAI) increase the risk of anal cancer by 33% over the general population. In the general population, the rate of anal cancer is approximately 0.9 cases per 100,000. In patients with a history of RAI, the rate approaches 35 cases per 100,000 which is equivalent to the prevalence of cervical cancer (3). Smokers are eight times more likely to develop anal cancer. There has been much discussion about tailoring treatment decisions in HIV+ patients with anal cancer. This review focuses on squamous cell carcinomas of the anal canal which comprise 80 to 90% of all anal cancers diagnosed and highlight key issues in the management of HIV+ anal cancer patients including recent clinical trials.