How are HIV and AIDS related to cancer?
People with HIV infection or AIDS can get cancer, just like anyone else. They are actually more likely to get some types of cancer than people who are not infected. In fact, some types of cancer occur so often in people with AIDS that they are considered AIDS-defining conditions – that is, their presence in a person infected with HIV is a clear sign that full-blown AIDS has developed.
Some other cancers are more common in people with HIV or AIDS than people who are not infected, but the reasons for the increased risk aren't clear. In some cases these cancers may be able to develop and grow more quickly because of a weakened immune system brought on by the infection itself. In other cases it may be because people with HIV infection or AIDS are more likely to have certain other risk factors for cancer, such as being smokers.
Many cancers are no more or less common in people with HIV infection or AIDS than in people who are not infected.
The cancers that define a person with HIV as having AIDS include:
- Kaposi sarcoma
- Non-Hodgkin lymphoma (especially primary central nervous system lymphoma)
- Invasive cervical cancer
In developed countries like the United States, the cancer picture in HIV has been changing as HIV treatment has improved. For example, Kaposi sarcoma and non-Hodgkin lymphoma have become less common as more people have gotten effective anti-HIV treatment. The use of anti-HIV drugs has also led to better cancer survival rates, as many people are now able to get full doses of chemotherapy and other standard cancer treatments, which may not have been possible in the past.
Kaposi sarcoma (KS) was once an uncommon cancer that mainly affected older men of Mediterranean or Jewish ancestry, organ transplant patients, or young men in Africa. This form is called classic KS or endemic KS. But in the past few decades, most KS cases in the United States have been linked to HIV infection in men who have sex with men. These cases are called epidemic KS (or AIDS-related KS).
It is now known that KS in people with HIV is related to a second viral infection. This virus is called human herpes virus 8 (HHV-8), also known as Kaposi sarcoma-associated herpes virus (KSHV). HHV-8 does not seem to cause disease in most healthy people. Infection with HHV-8 is common in the United States among men who have sex with men, but it can also be shared through sex between men and women. The HHV-8 virus is found in saliva, which may be one of the ways it is passed to others.
In most cases, epidemic KS causes dark purplish or brownish spots (called lesions) on the skin or in the mouth. KS may also affect the lymph nodes and other organs, such as the digestive tract, lung, liver, and spleen.
When they are first diagnosed, some people with HIV and KS have no other symptoms, especially if their only lesions are on the skin. But many – even those with no skin lesions – have swollen lymph nodes, unexplained fever, or weight loss. Over time, epidemic KS spreads throughout the body. If KS involves a lot of the lung or intestine, it can be fatal.
Non-Hodgkin lymphoma (NHL) is a cancer that starts in lymphoid tissue and may spread to other organs. It is more common in people with HIV infection or AIDS, but fewer people are developing it since anti-HIV drugs have been in common use.
There are many different types of non-Hodgkin lymphoma, but certain types are more common in people with AIDS. One of these is primary central nervous system (CNS) lymphoma, which starts in the brain or spinal cord. Symptoms of CNS lymphoma can include seizures, facial paralysis, confusion, memory loss, and feeling tired. AIDS-related NHL can also include certain types of fast-growing lymphomas, including diffuse large B-cell lymphoma and Burkitt lymphoma.
The outcome for patients with AIDS-related NHL depends on the type of lymphoma and on the person's immune function, as well as other factors. People with advanced NHL, a low CD4 (helper T-cell) count, and/or who don't get anti-HIV drugs don't usually do as well as people without these factors.
Pre-cancerous cervical changes and invasive cervical cancer
Cervical cancer is a cancer of the cervix, the lower part of the uterus (womb). Like Kaposi sarcoma, cervical cancer is strongly linked to a viral infection. In this case, the virus is the human papilloma virus (HPV). HPV can be spread from person to person through sexual contact.
HIV-infected women are at high risk for getting cervical intraepithelial neoplasia (CIN). CIN is the growth of abnormal, pre-cancerous cells in the cervix. Over time, CIN can progress to invasive cervical cancer, in which the cancer cells grow into deeper layers of the cervix.
CIN must be treated to keep it from invading. This is done by removing or destroying the outer layers of cervical cells. Untreated CIN is more likely to progress to invasive cervical cancer in HIV-infected women than in women who don't have HIV. The standard treatments for CIN do not work as well in HIV-infected women as they do in women without HIV. The chance of the disease coming back after treatment is high, especially in women with very low CD4 (helper-T cell) counts.
HIV-infected women with invasive cervical cancer and good immune function tend to do well with surgery and the same treatments that women without HIV get. Women tend to fare better if they do not have AIDS, and those with high CD4 (helper T-cell) counts have better outcomes.
Other types of cancer are also more likely to develop in people with HIV than in people who are not infected, including:
- Anal cancer
- Hodgkin disease (Hodgkin lymphoma)
- Melanoma skin cancer
- Liver cancer
- Lung cancer
- Mouth and throat cancers
- Testicular cancer
Some other, less common types of cancer may also be more likely to develop in people with HIV.
The link between HIV and these cancers is still not fully understood. For some cancers, the higher risk in people who have HIV may be because of risk factors these people are more likely to have, rather than the HIV infection itself. For example, mouth, throat, and lung cancers are strongly linked with smoking, which is more common in people with HIV, and the link with HIV becomes much weaker if smoking status is taken into account. Cancers of the liver, mouth, and throat (as well as other cancers) are linked with heavy alcohol use, which is also more common in people with HIV.
Some of these cancers have been linked to infections with different viruses. These viruses can cause cancer in people with and without HIV, but the risk may be higher in people with HIV because their immune systems are less able to control the viral growth. For example, anal cancer and some mouth and throat cancers are linked to infection with HPV, the same virus that causes cervical cancer. Liver cancer is known to be more common in people infected with the hepatitis B or C viruses. Some types of lymphoma have been linked with viral infections as well.
Of course, as people with HIV are now living longer, they are also developing other cancers that are not clearly linked to HIV but are more common in older people, such as breast, colorectal, and prostate cancer.
Last Medical Review: 02/01/2012
Last Revised: 07/05/2012