People with an AIDS diagnosis are far more likely to develop some types of stomach and esophageal cancers than HIV-negative people, according to a study presented at the 102nd Annual Meeting of the American Association for Cancer Research, held April 2 to 6 in Orlando.

The risk for certain cancers is well known in people with HIV. Before the introduction of potent combination antiretroviral (ARV) therapy in the late 1990s, AIDS-related cancers, such as Kaposi's sarcoma and non-Hodgkin's lymphoma were most common. In the combination ARV era, however, the rates of several non-AIDS cancers, such as liver cancer and anal cancer, have risen dramatically and commanded research attention. Less is known, however, about cancers of the stomach and esophagus.

To explore this further, E. Christina Persson, PhD, and her colleagues from the National Cancer Institute in Bethesda, Maryland, analyzed data from the HIV/AIDS Cancer Match Study, a linkage of 15 U.S. HIV and cancer registries that includes data on nearly 600,000 people.

Persson's team found that there were 915 stomach and 222 esophageal cancers registered in people with AIDS diagnoses. Of those cancers, the majority were lymphomas, which is not surprising, as cancers of the immune system are common in people with HIV. In all, Persson and her colleagues found that stomach cancers were about six times more common in people with HIV than in the general population and esophageal cancers were about twice as common.

By far, the most common stomach or esophageal cancer was lymphoma of the lower stomach, with higher rates of both mucosa associated lymphoid tissue (MALT) lymphoma and non-MALT lymphomas, both of which are rarer types of non-Hodgkin's lymphoma, an AIDS-defining cancer. Cancers of the lower stomach are often tied to bacteria called Helicobacter pylori, which is a primary cause of stomach ulcers and which can be treated with antibiotics.

The risk for the lymphomas, said Persson, was expected. What was unexpected, she continued, was the increased risk of stomach tissue tumors (carcinomas). She theorized that the large size of the study allowed them to detect differences in risk that smaller studies had missed.

“This study is unique because of its large size, which allowed us to look more closely at the different histologic and anatomic subsites of the tumors,” Persson concluded. “It will be important for us to evaluate trends in risk over time, particularly in the modern HIV treatment era.”