Kaposi's sarcoma (KS) is a rare type of cancer. It is known to affect people with Jewish, Italian and African ancestry. It can also affect people with HIV (human immunodeficiency virus) infection or people who have had an organ transplant. It is more common in men.
KS develops in a different way to other types of cancers. Most cancers begin in one place in the body and may then spread to other places. KS can start in several areas of the body at the same time. It develops from cells that line blood and lymph vessels. These are called endothelial cells. Kaposi's Sarcoma can also affect internal organs such as the lymph nodes, lung, bowel, liver and spleen.
A main cause of KS is a virus called the human herpes virus 8 (HHV8). The virus infects the cells and it is thought that this causes them to become cancerous. Mostly HHV8 is a sexually transmitted virus and is a common infection. It can also pass in blood between drug users who share needles. But not everyone infected with HHV8 gets KS. So it is thought that there are other factors involved. Scientists agree that having a weakened immune system or certain types of infections along with HHV8, also play a part in a person developing KS.
KS growths are called lesions or tumours. External lesions on the skin are the most common. They appear in different colours such as black, brown, blue, red or deep purple. These skin lesions usually start out very small and flat. They do not cause any pain or itching and seem harmless. They can look like a bruise, and do not lose their colour when pressed. As they grow, they may start to stick up above the surrounding skin and grow into each other giving the appearance of patchwork. They may grow very slowly and show no changes for a few months. But some develop more quickly, with new lesions appearing weekly.
The signs and symptoms of the lesions are different if they are on the inside of the body. These internal lesions can grow in body organs, such as the lymph nodes or lungs. The symptoms you have depend on which organs are affected. If KS is in the lymph nodes, which is common in AIDS related KS, you may have some swelling of your arms and legs. Doctors call this lymphoedema. KS cells block the flow of lymph fluid through the lymphatic system. This causes swelling in the body tissues. It can be quite uncomfortable. There is no cure for this, but treatment can help to control lymphoedema. The earlier you have lymphoedema diagnosed and treated, the easier it is to control. So if you have any swelling that you think may be lymphoedema, do tell your doctor.
The only way to definitely tell if you have a Kaposi’s sarcoma is to examine a tissue sample (biopsy) under a microscope. Usually, you can have this test with a local anaesthetic. But this depends on where the lesion is and on how large it is. If your doctor thinks you may have KS in the lungs, you will need a bronchoscopy to confirm the diagnosis. If your doctor thinks you may have KS in your digestive system, you will need a test called an endoscopy to diagnose it.
The 4 main types of KS are
- Classic KS
- Endemic or African KS
- Transplant KS found in people with weakened immune systems
- AIDS related KS
This type of KS is very rare and is usually only found on the skin, mainly on the lower legs and feet. It is most common in older men of Jewish or Mediterranean origin. It is a slow growing cancer and does not usually cause any problems. In the early stages, it doesn't usually need treatment. If the lesions are large and in very visible areas on the body, you may have radiotherapy to get rid of them. Or your doctor may suggest freezing them with liquid nitrogen or removing them with a small operation.
As the name suggests, this type of KS is found in parts of Africa, where HHV8 infection is common. It is faster growing than classic KS. It is more common in men, but women and children of all ages may develop it. Your doctor will treat this type of KS the same way as classic KS but may use chemotherapy if the other treatments do not work.
People who have weakened or damaged immune systems are most likely to develop this type of KS. For example, people who have had an organ transplant operation. These people need to take drugs to stop their bodies rejecting the donated organ. These drugs suppress the immune system. This type of KS is also very rare. Reducing or changing the immunosuppressive drugs usually improves it. If that doesn't help, it may be necessary to treat the KS with radiotherapy or chemotherapy.
This is the most common and fastest growing type of KS. If you have AIDS, your immune system is weakened. This increases your risk of developing KS. The treatment you have for this type of KS depends on how well you are and whether or not you are well enough to cope with the side effects of treatment.
Usually you have chemotherapy if the KS has spread throughout your body. Treatment at this stage is palliative, which means it is used to treat symptoms rather than offer a cure. Usually you have 2 or more of these drugs
Newer chemotherapy drugs, called liposomal drugs, are now available to treat KS that is no longer being controlled by standard chemotherapy. Liposomal drugs are wrapped up in a fatty covering called liposome. This makes the drug work better and causes less severe side effects. It includes the drugs doxorubicin liposome (Doxil or Caelyx) and daunorubicin liposome (DaunoXome). There is more information about chemotherapy and its side effects in the main chemotherapy section.
In the SCART trial, researchers are looking at a new drug called selumetinib for people with KS who are having treatment for HIV. Selumetinib is a type of biological therapy. It works by blocking a protein that sends signals to cells telling them to divide and grow. So it may stop cancer cells from growing. The aims of this early trial are to find out the best dose of selumetinib to give with treatment for HIV, and to see how well selumetinib works.
For more information about trials go to the trials and research section.
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