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Kaposi's Sarcoma

Kaposi’s sarcoma is a rare type of cancer that can affect both the skin and internal organs.

The most common initial symptom of Kaposi’s sarcoma is the appearance of red or purple patches on the skin. The patches then grow into lumps known as nodules.

Kaposi’s sarcoma can also damage the internal organs, which can lead to a range of symptoms, depending on which organs are affected. Possible symptoms include:

• breathlessness
• bleeding gums
• coughing up blood
• feeling sick (nausea)
• being sick (vomiting)
• stomach pain
• stomach swelling
• diarrhoea
• leg swelling

Read more about the symptoms of Kaposi’s sarcoma.

Causes

Unlike most types of cancer, the cause for Kaposi’s sarcoma has been identified. The condition is caused by a virus known as the human herpesvirus type 8 (HHV-8). The virus is also sometimes referred to as the Kaposi's sarcoma associated herpes virus (KSHV).

HHV-8 is a relatively common virus. As many as 1 in 20 people possibly have the virus in their body. In most cases, HHV-8 doesn't cause any noticeable symptoms. The majority of people with the virus won't go on to develop Kaposi’s sarcoma.

However, certain groups of people who are vulnerable to the effects of HHV-8 (see below) go on to develop Kaposi’s sarcoma. These are usually people whose immune system isn't working properly, either because they have another condition (a cancer or infection) or, they have received an organ transplant and have been given medication to allow the transplant to work.

Read more about the causes of Kaposi’s sarcoma.

Types of Kaposi’s sarcoma

There are four main types of Kaposi’s sarcoma, which are outlined below.

HIV-related Kaposi’s sarcoma

Kaposi’s sarcoma often affects people whose immune systems have been severely weakened by HIV.

During the 1980s, as many as 1 in 5 people with HIV or AIDS developed Kaposi’s sarcoma.

However, following advancements in treatment during the mid 1990s for HIV, particularly the introduction of a range of  medications known as highly active antiretroviral therapy (HAART), the number of people with HIV who were affected by Kaposi’s sarcoma fell by about 90%.

Endemic African Kaposi’s sarcoma

Endemic African Kaposi’s sarcoma is common in parts of Africa and is one of the most widespread types of cancer in that region, accounting for 1 in every 10 cases of cancer in Africa. The condition is particularly widespread in:

• Uganda
• the Congo (both the Democratic Republic of the Congo and the Republic of the Congo)
• Zambia

Many people from sub-Saharan Africa are also infected with HIV as well as HHV8. Therefore, it's highly likely that many cases of so-called ‘endemic’ African Kaposi’s sarcoma were and are, in fact, due to undiagnosed HIV infection.

‘Endemic’ African Kaposi’s sarcoma that's not HIV-related is thought to develop as a result of a pre-existing genetic vulnerability to the virus that causes it.

Classic Kaposi’s sarcoma

Classic Kaposi’s sarcoma is a rare condition that accounts for only 1 in every 500 cases of cancer in England. The condition mainly affects middle-aged and elderly men of Mediterranean or Ashkenazi Jewish descent.

Ashkenazi Jews are people who are descended from Jewish communities that lived in Central and Eastern Europe. Most Jewish people in England are Ashkenazi Jews.

It is thought that people who develop classic Kaposi’s sarcoma were born with a pre-existing genetic vulnerability to the HHV-8 virus.

Transplant-related Kaposi’s sarcoma

Transplant-related Kaposi’s sarcoma is an uncommon complication of organ transplants. In England, an estimated 1 in every 200 people who have an organ transplant develop Kaposi’s sarcoma.

Following an organ transplant, medication is usually taken that weakens the immune system (immunosuppressants) and prevents the body rejecting the new organ. However, when a person’s immune system is weakened, they're more vulnerable to the HHV-8 virus.

Treatment

Kaposi’s sarcoma can be treated using a combination of anti-HIV medication (if HIV-infected), chemotherapy, radiotherapy and surgery. HIV-related Kaposi’s sarcoma is usually a sign that a person’s HIV is being poorly controlled. So if they're not receiving HAART, this should be started. If they're on treatment, this may need to be reviewed to ensure that their HIV is well-controlled.

Read more about the treatment of Kaposi’s sarcoma.

Outlook

In England, the outlook for people with Kaposi’s sarcoma is usually relatively good when compared to other types of cancer.

Provided people with HIV-related Kaposi’s sarcoma get access to HAART early on in their HIV disease, their outlook will also be relatively good, and the condition will often go into remission (the symptoms will go away). If not, chemotherapy and radiotherapy can also relieve symptoms.

Classic Kaposi’s sarcoma is a very slow-growing form of cancer that often has no impact on a person’s natural lifespan.

Provided people with HIV- or AIDS-related Kaposi’s sarcoma get access to HAART, their outlook will also be relatively good, and the condition will often go into remission (the symptoms go away).

Transplant-related Kaposi’s sarcoma can usually be successfully treated by adjusting a person’s dosage of immunosuppressants.

Due to the relatively good outlook, deaths due to Kaposi’s sarcoma are now very rare. For example, during 2009, there were only seven deaths as a result of Kaposi’s sarcoma in England and Wales. However, it's important to realise that a complete cure for all types of Kaposi’s sarcoma isn't always possible, and there's a chance that the condition could reoccur in the future.

Symptoms

The symptoms of Kaposi’s sarcoma vary depending on whether the lesions or growths develop. The skin and the organs are most commonly affected.

The skin

Any part of the skin, including inside the mouth, can be affected by Kaposi’s sarcoma.

Small, painless, flat areas (lesions) or lumps usually develop first. The lesions can be different colours, including brown, red, blue and purple. They can look similar to bruises but, unlike bruises, they don't lose their colour when they're pressed.

The lesions are the result of multiple abnormal cell growths (tumours), which affect small blood vessels under the skin.

Lesions that develop inside the mouth can become damaged when chewing. This can cause them to bleed, which can make speaking and eating more difficult.

Although Kaposi’s sarcoma growths usually start in one place, they can develop in more than one area. The growths often eventually merge into each other to form a single larger tumour, giving a patchwork appearance.

The internal organs

The internal organs most commonly affected by Kaposi’s sarcoma are the lymph nodes, lungs and the digestive system.

The symptoms of Kaposi’s sarcoma 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 it is caused by the Kaposi’s sarcoma cells blocking the flow of fluid through the lymph nodes. As a result, the fluid in the tissue backs up, causing swelling in the body’s tissues.

Read more about lymphoedema.

In cases where the lungs are affected, symptoms may include breathlessness. Where the digestive system is affected, symptoms can include feeling sick and being sick.

Causes

Cancer begins when there's a change in the coding information in cells that tells them when to grow and replicate. 

The code is read from the deoxyribonucleic acid (DNA) that's found in all human cells. A change to the code is known as a mutation, and it can alter the instructions that control cell growth.

This means that cells carry on growing instead of stopping when they should. This results in the cells reproducing in an uncontrollable manner and producing a lump of tissue that's known as a tumour.

The human herpesvirus 8 (HHV-8)

Kaposi’s sarcoma 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 workings of cells, causing them to reproduce uncontrollably.

HHV-8 doesn't cause Kaposi’s sarcoma in everyone who develops the virus. The virus only seems to cause Kaposi’s sarcoma in people with:

• a weakened immune system – this is thought to be the reason why people develop HIV or AIDS-related Kaposi’s sarcoma and transplant-related Kaposi’s sarcoma
• an inherited (genetic) vulnerability to HHV-8 – this is thought to be the reason why people develop either classic Kaposi’s sarcoma or ‘endemic’ African Kaposi’s sarcoma 

Although HHV-8 was first identified in 1994, there's still no firm evidence as to how the virus is spread. 

One method of transmission of HHV-8 appears to be through unprotected anal sex. This is because rates of HHV-8 in some European and North American countries show that the virus is almost always more widespread in men who have sex with men.

However, this doesn't explain how many heterosexual African men and women and their children acquire this common infection with HHV-8.  Therefore HHV-8 may be passed on by some other means, e.g. through saliva. This means that the virus could be spread by kissing.

Treatment

Many hospitals use multidisciplinary teams (MDTs) to treat Kaposi’s sarcoma. These are teams of specialists who work together to decide about the best way to proceed with your treatment.

Members of your MDT may include a:

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

You may also be assigned a key worker who will usually be a specialist nurse. They will be responsible for co-ordinating your care.

Deciding on the treatment that's best for you can often be confusing. Your cancer team will recommend what they think is the best treatment option, but the final decision will be yours.

Before visiting hospital to discuss your treatment options, you may find it useful to write a list of questions that you'd like to ask the specialist. For example, you may want to find out the advantages and disadvantages of particular treatments.

Your treatment plan

The treatment of Kaposi’s sarcoma will depend on:

• the severity of your symptoms
• the stage of the cancer (see Kaposi’s sarcoma - diagnosis for more information)
• the type of Kaposi’s sarcoma
• your general health

Treatment plans can vary from person to person, but typical treatments for each type of Kaposi’s sarcoma are outlined below.

HIV-related Kaposi’s sarcoma

If you have HIV-related Kaposi’s sarcoma, you are usually given a course of combination highly active antiretroviral therapy (HAART) to help strengthen your immune system. If you're already on HAART, the types of medication and dosages may be changed. HAART may be followed by courses of radiotherapy or chemotherapy.

Classic Kaposi’s sarcoma

As classic Kaposi’s sarcoma spreads slowly, immediate treatment isn't usually required, and a policy of ‘watchful waiting’ may be recommended. This means that your MDT will delay treatment to see whether any symptoms progress. This is often recommended for older people when it's unlikely that the cancer will affect their natural life span.

If treatment is required, radiotherapy is usually used to treat cases of classic Kaposi’s sarcoma.

Endemic African Kaposi’s sarcoma

Endemic African Kaposi’s sarcoma is usually treated using a combination of radiotherapy and chemotherapy.

Transplant-related Kaposi’s sarcoma

Transplant-related Kaposi’s sarcoma is usually treated by reducing or stopping your immunosuppressants. The aim is to strengthen your immune system enough to fight off the human herpes virus 8 (HHV-8) while ensuring that your body doesn't reject the transplanted organ.

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

Surgery

If the lesion is small, it may be removed using surgery. Your GP will inject a local anaesthetic into the affected area to numb the lesions before they're surgically removed.

Cryotherapy – in which the lesions are frozen using liquid nitrogen – is also sometimes used.

Chemotherapy

Chemotherapy is where powerful medication is used to treat cancer by destroying 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
• increased vulnerability to infection

Liposomal chemotherapy is often used to treat Kaposi’s sarcoma. The medicines that are usually 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 Kaposi’s sarcoma cells while doing as little harm as possible to healthy cells. It can be very effective in reducing the symptoms of internal Kaposi’s sarcoma, such as breathlessness and swelling of the arms and legs.

Possible side effects of radiotherapy include:

• tiredness
• sore skin (particularly for people with HIV or AIDS)
• stiff joints and muscles
• feeling sick (nausea)
• temporary hair loss
• loss of appetite
• loss of libido (interest in sex)
• early menopause
• temporary erectile dysfunction (inability to obtain or maintain an erection) in men

Most of these side effects gradually disappear after the course of treatment has been completed.

Immunotherapy

Immunotherapy is sometimes used to treat transplant-related Kaposi’s sarcoma. Also known as biological therapy, immunotherapy uses special proteins that have been genetically engineered in a laboratory. Normally, the body doesn't regard the cancerous cells as foreign objects so the immune system doesn't attack them.

In immunotherapy, special antibodies are created in a laboratory that change the make-up 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-alpha is one of the most common types of medicines used in immunotherapy. It's 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
• aching in the back, joints and muscles