Kaposi's sarcoma

Page last reviewed: 13/07/2011

Kaposi's sarcoma (KS) is a type of cancer. It causes growths, mainly under the skin, although they can grow in the lining of the mouth, nose, throat and other organs.

It differs from other cancers as it starts in several areas of the body at once. Most cancers start in one place and then spread.

KS causes lesions (abrasions) or tumours (growths). They most commonly appear on the skin as small, flat, coloured lesions that can be brown, blue, red or deep purple. Lesions can also develop on the internal organs. The organs which are most affected are:

  • lymph nodes (part of the immune system),
  • lungs, and
  • digestive system, including the bowel, liver and spleen.

Types of Kaposi's sarcoma

There are four types of KS:

  • HIV- or AIDS-related KS,
  • classic KS,
  • endemic or African KS, and
  • transplant-related KS.

HIV- or AIDS-related KS

KS can develop in people whose immune system has been severely weakened by HIV or AIDS. It mostly affects gay men with HIV or AIDS. KS rarely affects women or straight men with HIV or AIDS. It is thought that this is because the virus that causes KS is spread during unprotected anal sex.

HIV- or AIDS-related KS used to be the most common complication affecting gay men living with HIV and was a leading cause of death. This is no longer the case due to anti-HIV medications, known as highly active antiretroviral therapy (HAART), that were developed in the 1990s.

Classic KS

Classic KS is a rare condition. It usually only affects men between 50 and 70 years of age who are of Mediterranean or eastern European descent. It is thought that people who develop classic KS were born with a pre-existing genetic vulnerability to the virus that causes it.

Endemic or African KS

Endemic KS is common in parts of Africa and is one of the most widespread types of cancer in that region. As with classic KS, endemic KS is thought to develop due to a pre-existing genetic vulnerability to the virus that causes it.

The situation has recently been complicated by the HIV epidemic in Africa, and many people may now be more vulnerable to the virus because of a weakened immune system due to HIV or AIDS.

Transplant-related KS

Transplant-related KS is an uncommon complication of organ transplants. It is estimated that abot 0.5% of people who have an organ transplant develop KS.

People who have had an organ transplant usually take medication to weaken their immune system (immunosuppressants) to prevent their body rejecting the new organ. The weakening of their immune system makes them more vulnerable to the virus that cause KS.

Outlook

HIV- or AIDS-related KS

The outlook for HIV- or AIDS-related KS is variable and depends on a person's age and how weakened their immune system is. 

In an older person with a weakened immune system, the cancer often spreads aggressively to other parts of the body (metastasis).

The estimated survival rate for HIV- or AIDS-related KS is five years, although many people live a lot longer. The survival rate is expected to improve as medication for treating HIV improves.

Classic KS

The outlook for classic KS is good. The cancer tends to spread slowly and does not usually spread to other parts of the body. As classic KS primarily affects older people, those with the condition often die from other causes before the cancer progresses to a more serious stage.

Endemic KS

The outlook for endemic KS is poor, not least because access to treatment such as chemotherapy is often limited in parts of the world where endemic KS is widespread.

Transplant-related KS

The outlook for transplant-related KS is generally good because the condition can usually be successfully treated by reducing or stopping a person's course of immunosuppressants. However, this carries the risk that their body will reject the donated organ.

Lesions

A lesion is an abnormal change in an organ or body tissue because of injury or disease.

Lymph nodes

Lymph nodes are small oval tissues that remove unwanted bacteria and particles from the body.

Immune system

This is the body's defence system, which helps protect it from disease, bacteria and viruses.

Lungs

Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Liver

The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.

Recipients

A recipient is a person that receives donated blood, tissue or an organ from another person.

Radiotherapy

In radiotherapy, X-rays are used to treat disease, especially cancer.

Chemotherapy

Chemotherapy is the treatment of an illness or disease with a chemical substance. It is used in the treatment of cancer.

Page last reviewed: 13/07/2011

The symptoms of Kaposi's sarcoma (KS) vary according to where the lesions or growths develop.

The skin

Any part of the skin, including the inside of the mouth, can be affected by KS. KS usually appears as small, painless flat areas (lesions) or lumps. They can be different colours including brown, red, blue and purple. They often look like bruises but do not lose their colour when pressed like a bruise does.

Although KS growths may start in one place, they can develop in more than one area. The growths often eventually merge into each other to form a larger tumour, giving a patchwork appearance.

The internal organs

The internal organs most commonly affected by KS are the lymph nodes, lungs and organs of the digestive system. The symptoms of KS depend on which organs are affected.

When the lymph nodes are affected, there may be swelling in the arms and legs, which can be very painful and uncomfortable. This is known as lymphoedema and is caused by the KS cells blocking the flow of fluid through the lymph nodes. As a result, the tissue fluid backs up, causing swelling in the body's tissues.

When the lungs are affected, symptoms may include breathlessness. When the organs in the digestive system are affected, symptoms include nausea, vomiting and bleeding.

Page last reviewed: 13/07/2011

How cancer begins

Cancer begins with an alteration to the structure of DNA, which is found in all human cells. DNA provides our cells with a basic set of instructions such as when to grow and reproduce.

A change in its structure, called a genetic mutation, can alter these instructions and cause the cells to reproduce uncontrollably. This produces a lump of tissue known as a tumour.

How cancer spreads

Left untreated, cancer can quickly grow and spread to other parts of the body.

Cancer usually spreads through the lymphatic system. This is a series of glands (or nodes) located throughout the body, similar to the blood circulation system.

Lymph glands produce many specialised cells that your immune system needs to fight infection. Once the cancer reaches the lymphatic system, it can spread to any other part of your body, including your bones, blood and organs.

The human herpesvirus 8 (HHV-8)

Kaposi's sarcoma (KS) is caused by a virus called the human herpesvirus 8 (HHV-8), which is also known as the Kaposi's sarcoma-associated herpesvirus (KSHV).

It is thought that HHV-8 contains genetic material that interferes with the normal working of cells, causing them to reproduce in an uncontrollable manner.

HHV-8 does not cause Kaposi's sarcoma in everyone who contracts the virus. Instead, it only seems to cause Kaposi's sarcoma in:

  • people who have an inherited (genetic) vulnerability to HHV-8, or
  • people with a weakened immune system.

HHV-8 was first identified in 1994 but, as yet, there is no firm evidence as to how the virus is spread.

However, there is good circumstantial evidence that HHV-8 can be spread during unprotected anal sex. The rates of HHV-8 in specific countries show that the virus is almost always more widespread in the gay community than in heterosexuals.

There is circumstantial evidence that HHV-8 can be passed on through saliva. This means the virus could also be spread by kissing.

Page last reviewed: 13/07/2011

Before diagnosing Kaposi's sarcoma (KS), your GP will ask you about your general health and carefully examine your skin.

If you have HIV or AIDS, the examination may be carried out by a member of your local HIV clinic who has experience of treating KS. They may take digital photos of any suspected lesions and send them to specialists, such as an oncologist (cancer specialist) or a dermatologist (skin specialist).

If they think you may have KS, you will probably be referred for further testing. If you have HIV or AIDS, the tests will usually be carried out at a specialist centre where staff are experienced in treating complications of HIV and AIDS.

If you do not have HIV or AIDS, you may be referred to a specialist clinic that treats cancers of the skin.

Biopsy

A biopsy is the most effective way to confirm a diagnosis of KS. This involves taking a small sample of cells from an affected area of skin. The sample is then checked at a laboratory for the presence of KS cells.

Endoscopy

An endoscopy may be carried out if it is suspected that you have KS in your digestive system. The procedure involves inserting a thin, flexible tube called an endoscope down your throat. It allows the GP to look inside parts of your digestive system, such as the bowel, liver and spleen, for any abnormalities or signs that KS is present. They may take a biopsy if they find anything suspicious.

If you have an endoscopy, you will be given a mild sedative to help you relax. A local anaesthetic will be sprayed on to your throat to prevent discomfort as the tube is passed down.

A similar method can be used to look at the lungs (bronchoscopy) if it is suspected that you have KS in your lungs.

Computerised tomography scan

You may have a computerised tomography (CT) scan if it is suspected that KS has spread to your lymph nodes or other parts of your body.

A CT scan works by taking a series of X-rays which build up a three-dimensional picture of the inside of the body. You may be given a radioactive dye to drink before the CT scan to allow particular areas of your body to been seen in greater detail.

Page last reviewed: 13/07/2011

.It can be difficult to decide which treatment is best for you. Your multi-disciplinary cancer team will make recommendations but the final decision will be yours.

Before going to hospital to discuss your treatment options, you may want to write a list of questions to ask the specialist. For example, you may want to find out what the advantages and disadvantages are of particular treatments.

Treatment plans

The treatment of KS depends on:

  • the severity of symptoms,
  • the size and location of the lesions,
  • the type of KS, and
  • your general health.

Treatment plans can vary from person to person, but the usual plan for each type of KS is outlined below.

HIV- or AIDS-related KS

If you have HIV- or AIDS-related KS, you will usually be given a course of highly active antiretroviral therapy (HAART) to help strengthen your immune system. If you are already on HAART, the types of medication and dosages may be changed. HAART may be followed by courses of radiotherapy and/or chemotherapy.

Classic KS

As classic KS spreads slowly, immediate treatment is not usually required and a policy of 'watchful waiting' may be recommended. This means that your MDT will delay treatment to see if any symptoms of progressive cancer develop. This is often recommended for older people when it is unlikely that the cancer will affect their natural life span.

If treatment is required, radiotherapy is normally used to treat classic KS.

Endemic KS

Endemic KS is usually treated using a combination of radiotherapy and chemotherapy.

Transplant-related KS

Transplant-related KS is usually treated by reducing or stopping your immunosuppressants. The goal is to strengthen your immune system enough to fight off the humanherpes virus 8 (HHV-8) while ensuring that your body does not reject the transplanted organ.

It may take some time to find the best balance between these two treatment goals.

Types of treatment

The types of treatment that are used for KS are outlined below.

HAART

HAART involves using a combination of medicines that interrupt the reproductive cycle of the HIV virus. This helps to prevent the virus from spreading quickly as well as protecting and strengthening your immune system.

As HIV can quickly adapt and become resistant to a single medicine, a combination of medicines is required.

In some people, the medicines used to treat HIV will cause side effects. These usually improve after a few weeks as your body gets used to the medicines. Common side effects of HIV medication include:

  • nausea,
  • tiredness,
  • diarrhoea,
  • skin rashes,
  • mood changes, and
  • gaining fat on one part of your body while losing it on another (lipodystrophy).

Surgery

If the lesion is small, surgery may be used to remove KS from the skin. Your doctor will inject a local anaesthetic into the affected area to numb the lesions before they are surgically removed.

Cryotherapy may also be given. This freezes the lesions using liquid nitrogen.

Chemotherapy

Chemotherapy uses medicines to treat cancer. The medicines destroy rapidly growing cancer cells.

The medicines can either be given through a drip into a vein in your arm (intravenously) or as a tablet that is taken orally (by mouth). If the lesion is small, chemotherapy may be injected directly into it. This is called intralesional chemotherapy.

Chemotherapy can cause side effects including:

  • vomiting,
  • hair loss,
  • tiredness, and
  • increased vulnerability to infection.

Liposomal chemotherapy is often used to treat KS. The medicines that are normally used in chemotherapy are covered in a fat-based coating called liposome. The extra coating means there are fewer side effects and the medication works more effectively.

Radiotherapy

Radiotherapy uses high-energy rays to pinpoint and destroy the KS cells while doing as little harm as possible to healthy cells. It can be very effective in reducing symptoms of internal KS, such as swelling, pain and bleeding.

Possible side effects of radiotherapy include:

  • tiredness,
  • sore skin (particularly for people with HIV or AIDS),
  • stiff joints and muscles,
  • nausea,
  • temporary hair loss,
  • loss of appetite,
  • loss of libido (interest in sex),
  • early menopause, and
  • temporary impotence in men.

Most side effects gradually disappear once the course of treatment is over.

Immunotherapy

Immunotherapy, also known as biological therapy, is often used alongside other treatments such as HAART. Immunotherapy uses special proteins that have been genetically engineered in a laboratory.

Normally, the body does not regard the cancerous cells as foreign objects so the immune system does not attack them.

In immunotherapy, special antibodies are created in a laboratory that change the composition of cancerous cells so that the immune system regards them as foreign objects. The immune system then starts to attack the cells in the same way that it would normally attack an infection.

Interferon is one of the most common types of medicines used in immunotherapy. It is usually given by daily injections into the skin over a number of weeks.

Side effects of immunotherapy include:

  • chills,
  • high temperature (fever) of 38°C (100.4°F) or above,
  • loss of appetite,
  • nausea,
  • headaches,
  • tiredness, and
  • aching in the back, joints and muscles.

Multi-disciplinary teams (MDTs) are made up of different specialists including:

  • dermatologist (skin specialist),
  • plastic surgeon,
  • clinical oncologist (a specialist in the non-surgical treatment of cancer),
  • virologist (a specialist in the treatment of viruses),
  • pathologist (a specialist in diseased tissue),
  • social worker,
  • psychologist, and
  • counsellor.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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