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Longevity improved for those with HIV/AIDS but cancer risk increased



For the Gazette
Monday, July 09, 2018

While the vast majority of people with HIV in the United States are doing well with treatment, they appear to have a higher risk of developing certain cancers.

Since the first cases of AIDS were reported almost four decades ago, tremendous progress has been made in understanding and managing this once almost always fatal disease. Although not yet curable, most people treated for HIV today can expect to survive nearly as long as someone without the virus due to advances in therapy.

Following discovery of the cause of AIDS (human immunodeficiency virus or HIV) in 1984, researchers and clinicians quickly learned that the virus infects and destroys T cells (a type of lymphocyte), which help to orchestrate the body’s immune response to many infections.

In patients with advanced HIV (AIDS) who have low numbers of T cells, the ability to fight off many other infections (viruses, fungi and bacteria) is greatly diminished. Many of these “opportunistic” infections would not normally cause a problem in a person with a healthy immune system.

Patients with AIDS were also found to have a high incidence of certain types of cancer including Kaposi’s sarcoma, cervical cancer and non-Hodgkin’s lymphoma.

The mortality rate in patients with HIV remained high until the mid-1990s when studies showed that a combination or “cocktail” of three (antiretroviral) medications was much more effective and durable compared to only one or two medications.

This led to many fewer infections and incidence of HIV-related cancers and dramatic improvements in survival.

In the 20-plus years since, many even more potent antiretroviral medications have been developed, and with many fewer side effects. These medications prevent HIV from reproducing and help the body maintain a near-normal immune system.

Today, patients with access to HIV medications can expect to live nearly as long as someone without HIV.

As treated patients with HIV are living longer there has been an increased awareness of non-AIDS defining conditions, that is, medical conditions not previously seen in this population.

For example, it is now recognized that patients living with HIV have a higher risk of heart disease and diabetes, compared to patients without HIV infection. This may be due to a high amount of inflammation in the bloodstream as well as the fact that patients are living into middle and late age when heart disease is more common.

Recently, it has been reported that patients with HIV also have a higher risk of certain cancers which were not previously known to be associated with HIV. These include liver cancer, cancer of the mouth and throat, anal cancer, Hodgkin’s lymphoma and lung cancer. It is not completely understood why there is a higher rate of these cancers. It is likely due to multiple factors.

Chronic inflammation and a longer lifespan may explain part of their increase in those with HIV.

Another factor may be that although antiretroviral medications significantly lower the amount of HIV in the bloodstream, the immune system (including T cells) may not completely recover in all patients. T cells and other immune cells may be less efficient in “immune surveillance” (finding and ridding the body of the initial cancer cells before they can grow into a tumor).

Many of these cancers are caused by oncogenic viruses — viruses causing cancer — including Epstein-Barr virus (Hodgkin’s lymphoma), hepatitis B and C (liver cancer), and human papillomavirus (mouth and throat and anal cancers).

These viruses, like HIV, can be transmitted through sexual contact and through the use of shared needles.

Lung cancer, which is also more common among those with HIV than the general population (even when the higher smoking rate in HIV-infected patients is taken into account), is not known to be associated with any cancer-related viruses. The specific reasons for the increase in rates of lung cancer are not completely understood.

An increased awareness of these cancers in patients with HIV is certainly important for patients and their health care providers. Whether increased cancer screening is warranted remains to be determined and will need to studied. For example, it is known that low-dose chest CT scans of heavy smokers can detect some lung cancers early and improve outcomes. It is not known if this benefit is also seen in smokers with HIV.

Decreasing cigarette smoking is obviously likely to be beneficial. Protection against cancer-causing viruses by appropriate vaccination is also important. These include HPV and hepatitis B vaccines. And, of course, starting treatment as soon as someone is diagnosed HIV-positive is known to particularly reduce risk of cancer incidence in this population of patients.

Editor’s note: Dr. Daniel J. Skiest works in the Division of Infectious Diseases, Baystate Health in Springfield. Health professionals from Baystate contribute a monthly column to this space.