Results from two new studies, including a large study from the National Cancer Institute, confirm that cases of non-AIDS-defining cancers are increasing among people with AIDS.

“The changing number and types of cancer for people with HIV/AIDS highlights the need for research focusing on the specific cancer prevention needs of this population, including smoking cessation, treatment of hepatitis B and C viral infections, and prevention and screening for HPV-related cancers,” said Dr. Eric A. Engels, lead investigator of the National Cancer Institute (NCI) study, in a press release.

Cancer is now a leading cause of death for people with HIV. Some studies have estimated that about 30 percent to 40 percent of people with HIV will be diagnosed with cancer.

AIDS-defining cancers are cancers that are common in people with advanced HIV infections as a result of their weakened immune systems. These types of cancer include Kaposi’s sarcoma, non-Hodgkin’s lymphoma, and cervical cancer. Although they can appear in people who are HIV-negative, the development of these cancers in a person with HIV is closely tied to the health of the immune system. As a result, a person with HIV who has an AIDS-defining cancer is usually classified as having AIDS.

Previous studies have indicated that rates of AIDS-defining cancers have decreased as a result of improved health due to antiretroviral therapy, particularly highly active antiretroviral therapy (HAART) (see related AIDS Beacon news).

In contrast, developing a non-AIDS-defining cancer does not lead to a diagnosis of AIDS. Non-AIDS-defining cancers are in some cases more common in people with HIV than in the general population, but can occur even in people who carefully control their HIV infection.

As the life spans of people with HIV are increasing, so is their risk of developing non-AIDS-defining cancers, such as Hodgkin’s lymphoma, lung cancer, and anal cancer.

NCI Study Confirms Drop In AIDS-Defining Cancers, Rise In Non-AIDS-Defining Cancers

Results from the NCI study, carried out jointly with the Centers for Disease Control and Prevention, confirmed results of previous studies indicating that the rates of AIDS-defining cancers have dropped but the rates of non-AIDS-defining cancers are increasing in people with AIDS.

The study authors attributed the increase in non-AIDS-defining cancers to an aging AIDS population and a higher prevalence of risk factors such as smoking and hepatitis C infection compared to the general population.

The researchers estimated the number of cancers in the AIDS population by comparing HIV registries with cancer registries in 34 states. Results showed that from 1991 to 2005, nearly 80,000 cancers were reported in people with AIDS.

Further analysis showed that between 1991 to 1995 and 2001 to 2005, the number of AIDS-defining cancers dropped about three-fold while the number of non-AIDS-defining cancers increased three-fold. During the same time period, the AIDS population approximately quadrupled.

Anal cancers increased the most during this period, approximately eight-fold. Liver cancers increased five-fold, and lung cancers and Hodgkin’s lymphoma rates doubled.

Belgian Study Finds Older Age, Low Minimum CD4 Counts Are Risk Factors For Non-AIDS-Defining Cancers

Results from a second smaller study from Belgium showed that the primary risk factors for non-AIDS-defining cancers are age over 45 years and low minimum (nadir) CD4 cell counts (less than 200 cells per microliter of blood). The nadir CD4 cell count is defined as the lowest CD4 cell count measured after HIV infection.

In their study, the researchers from Belgium investigated the occurrence, risk factors, and outcomes of non-AIDS-defining cancers in 3,126 HIV-positive adults from the Brussels St-Pierre HIV cohort. They examined the medical records for these patients from January 2002 to March 2009.

During this period, 45 HIV-positive individuals were diagnosed with non-AIDS-defining cancers.

Consistent with the NCI study results, the researchers observed a higher rate of Hodgkin’s lymphoma, anal cancer, and liver cancer in people with HIV, particularly men, compared to the general population. HIV-positive women had higher rates of Hodgkin’s lymphoma and bladder cancer but lower rates of breast cancer compared to women in the general population.

Approximately 53 percent of patients with cancer were over the age of 45 years, compared to about 22 percent of patients without cancer. In addition, HIV-positive cancer patients had lower nadir CD4 cell counts (an average of 110 cells per microliter) compared to HIV-positive individuals without cancer (an average of 224 cells per microliter).

HIV patients with non-AIDS-defining cancers had a longer history of HIV infection and a two-fold higher rate of hepatitis C infection.

Results also indicated a 15-fold increase in risk of death for HIV-positive adults with cancer compared to individuals not diagnosed with cancer. Male patients lived longer after cancer diagnosis (32 months) than female patients (14 months). Women who had emigrated from sub-Saharan Africa had a particularly poor prognosis, possibly due to socio-economic factors such as low income.

About 54 percent of the HIV-positive cancer patients received chemotherapy. Thirty-two percent of these patients experienced complications related to infections, and 28 percent experienced blood complications, with anemia (a decrease in the number of red blood cells) being the most common.

In addition, 41 percent of cancer patients underwent surgery, with a complication rate of 32 percent, including two deaths. Forty-three percent of patients had radiotherapy, with 25 percent reporting complications, mostly rashes.

For more information on the NCI study, please see the Journal of the National Cancer Institute (abstract) or the NCI press release. For more information on the Belgian study, please see the Journal of the International AIDS Society.