What Is Kaposi’s Sarcoma?
Kaposi’s sarcoma (KS) is a form of cancer in which tumors with tiny blood vessels grow below the surface of your skin and in your mouth, nose, eyes, and anus. It can spread to your lungs, liver, stomach, intestines, and lymph nodes, the glands that help you fight infection.
Types of Kaposi’s Sarcoma
There are four types:
- Epidemic/AIDS-associated. This is the most common kind in the U.S. It affects people who have HIV. It’s known as an AIDS-defining illness because it’s on the CDC’s list of conditions that mean someone’s HIV infection has become AIDS.
- Classic. This type affects older men of Mediterranean, Middle Eastern, or Eastern European descent.
- Endemic. Children and young people from Africa get this kind of KS.
- Immunosuppressive. This kind affects people who have had organ transplants and take drugs that slow down their immune system.
Kaposi’s Sarcoma and HIV
Because people with HIV have weakened immune systems -- the body's main line of defense against germs and illnesses -- they're more likely to develop certain cancers, including Kaposi’s sarcoma. Most severe cases happen when someone has AIDS, but skin lesions can show up earlier. They're a sign that your immune system isn't at full strength.
Skin lesions tend to get worse when you also have other infections.
Antiretroviral therapy for HIV also treats KS, especially early on. Anti-HIV drugs have lowered the rate of KS cases by 80% or 90% from the early 1980s.
Kaposi’s Sarcoma Causes
KS is caused by the herpes virus HHV-8, also called Kaposi’s sarcoma-related herpesvirus (KSHV). It spreads mainly through saliva, such as during sexual contact or in interactions between a mother and child.
People with healthy immune systems can carry the virus without any problems. But it triggers cancers in people with weakened immune systems.
It affects eight times more men than women. Among people who have HIV, men who have sex with men are more likely to have the virus and to get Kaposi’s sarcoma.
Kaposi’s Sarcoma Symptoms
The most visible signs of KS are lesions on your skin: flat, painless spots that are red or purple on white skin and bluish, brownish, or black on dark skin. Unlike bruises, they don't change color when you press on them. They aren't itchy, and they don't drain. They're not dangerous.
New spots may show up each week. For some people, these lesions change slowly. They may grow into raised bumps or merge together.
When KS spreads, it can be life-threatening. You may have:
Your doctor may diagnose Kaposi’s sarcoma just by looking at your skin. To confirm it, they may take a sample of tissue from a spot and look at it under a microscope, which is called a biopsy. They might also do tests including:
- Fecal occult blood test. This looks for blood in your stool, which might mean KS is hurting your digestive tract.
- Endoscopy/colonoscopy. If you’re having stomach trouble, your doctor might want to look in your intestines with lighted tubes called endoscopes and colonoscopes.
- Bronchoscopy. If you have trouble breathing, they might look into your airways with a thin tube called a bronchoscope.
- Imaging tests. A CT scan or an X-ray can tell whether the cancer has spread to your lungs, your lymph nodes, or other parts of your body.
Kaposi’s Sarcoma Treatment
Your treatment will depend on how many lesions you have, how big they are, where they are, and how well your immune system is working.
In many cases, antiretroviral therapy is the best way to treat active Kaposi’s sarcoma. It may even clear up skin lesions.
If you have just a few lesions, your doctor can cut or freeze them off. It’s not a cure for KS, but it can make your skin look better.
If you have lots of lesions or the virus is affecting many areas of your body, you might get radiation therapy. This kills the cancer cells or keeps them from growing. A machine directs radiation toward the lesions on your skin, or your doctor may put radioactive needles, seeds, or wires inside you near the cancer.
If KS has spread, you'll need medications that go through your whole body to kill the cancer. Chemotherapy drugs for Kaposi's sarcoma include:
Another type of drug treatment, called biologic therapy, works by boosting your immune system. Your doctor may prescribe interferon alfa (Intron A) if your CD4 cell count (a type of white blood cell) is over 200 and you have a fairly healthy immune system.
Clinical trials are testing targeted therapies such as monoclonal antibody therapy and tyrosine kinase inhibitors. These treatments are aimed at attacking the cancer and keeping it from growing without hurting healthy cells.
Kaposi’s Sarcoma Prevention
There’s no vaccine to protect against the virus. The best way to keep from getting KS is to avoid things that put you at higher risk of HIV, such as having unprotected sex or injecting drugs with used needles. Medications called pre-exposure prophylaxis (PrEP) can also make you less likely to get HIV.
If you have HIV, a test can tell if you also have HHV-8. Antiretroviral therapy lowers the risk that it will become KS.
If you’ve had an organ transplant, some anti-rejection drugs can also lower your chance of getting KS.