HIV and Cancer

As I said in a previous post, I am going to write about the links between HIV infection and cancer.

Earlier this week, when I made a presentation to the Howe of Fife rotary club, one of the members told me that they had no idea that HIV infection can increase the risks of cancer. This highlighted to me the importance of needing to increase the awareness of cancer. HIV infection rates in Sub Saharan Africa are extremely high, which results in millions of people being predisposed to many types of cancer. In addition, the introduction of better treatment for HIV positive individuals has increased their life expectancy, resulting in the incidence of certain cancers to increase.

There are several cancers which when present mark the progression of HIV into AIDS. These include:

• Kaposi Sarcoma (KS)

1. rare in the HIV negative population
2. patients with HIV infection are 200-300 more likely to develop KS than those without
3. the use of the newest HIV medication actually reduces the risk of developing KS

• non-Hodgkin's Lymphoma (NHL)

1.  also known as aids related lymphoma
2. HIV infection variably increases the risk developing this cancer by between 40-400 times.

• invasive cervical cancer. (ICC)

1. although it is an AIDS defining cancer, the research linking ICC with HIV is still inconsistant

There are also other cancers, which although are not AIDS defining, have higher incidence rates in those with HIV infection compared to those who how are HIV negative. Research has shown that HIV infected people have a 2-3 fold increase in developing these types of cancer. These cancers are often described as Non Aids defining, Aids Associated malignancies or opportunistic cancers. These include

• Hodgkins Disease (HD)

1. HIV infection increases the risk of developing HD by 7-11 times compared to the general population

• Lung Cancer

1. HIV infected patients are 2-7 times more likely to develop lung cancer compared to HIV negative individuals
2. long term tobacco exposure is usually much lower in HIV infected patients as it is normally diagnosed at an earlier stage
3. The most recent treatment for HIV has caused an almost 9 fold increase in the rates of lung cancer, however this is probably more due to the increased life expectancy.

The prognosis cancer patients that are HIV postitive compared to those that are HIV negative tends to be much worse, irregardless of the type of cancer. This may be due to cancers being more aggressive in those that have compromised immune systems,. In addition, HIV patients, often present with much more advanced cancers at the time of diagnosis and at much younger ages.

The exact causes and reasons why HIV infection increases the risks of cancer is stil unclear. However there are several different hypothesis. The main one due to the bodies own lack of immune response. It may also be that AIDS defining cancers are related to cancer promoting viruses such as HPV. Also, the increased rate of general infections might increase the risk of cancer. However, it may be that other risk factors such as multiple sexual partners, drug use, increased alcohol/tobacco consumption may be the cause for increased cancer rates among HIV infected individuals.

Regardless of whether these cancers are directly related to HIV infection, treating cancer in HIV-positive patients remains a challenge because of drug interactions, compounded side effects, and the potential effect of chemotherapy on the patient.