Overview

Cancer is described as the uncontrollable growth and spread of cells in the body.¹ It can start almost anywhere in the human body, and it is made up of trillions of cells.¹ These cells are what we call cancerous, and can lead to the formation of abnormal masses called tumours.¹

Kaposi’s sarcoma is a rare type of cancer that can form purplish tumours on the skin, in the mouth, lymph nodes and other organs.²

Kaposi’s sarcoma is typically associated with advanced human immunodeficiency virus (HIV) infection, which weakens the immune system, though some individuals can be affected by this cancer without HIV.²   

How does Kaposi's sarcoma develop?

Kaposi’s sarcoma can cause the formation of tumours all over the body, ranging from organs to bones and muscles.²

Kaposi’s sarcoma develops from endothelial cells, which are cells that line blood vessels such as arteries and veins.² This allows the cancer to spread through the blood vessels and form tumours on the skin and even to the organs.²

While the defining feature of Kaposi’s sarcoma is tumours on the skin, gums and mouth, there are also some other tell-tale signs.²

What are the tell-tale signs of Kaposi’s sarcoma?

Tumours on the skin that start small and often look like bruises.² These tumours are typically painless, and they do not whiten when you press them.²

These tumours can multiply and spread across one part of the body or spread all over the body and, eventually, become large masses.²

There are different types of Kaposi’s sarcoma, depending on the symptoms, and they can vary from person to person.²

The factor that connects the different types of Kaposi sarcoma is a weakened immune system.² The cause of the weakened immune system is what largely determines the severity of the disease.²

There are 4 main types of Kaposi’s sarcoma:²

1. HIV-associated Kaposi’s sarcoma – This is a form of the cancer that affects individuals with HIV, which is known to be aggressive i.e. fast progressing²
2. Classic Kaposi’s sarcoma – This form mainly affects older men of Mediterranean or Eastern European descent and is slow progressing²
3. Transplant-related Kaposi’s sarcoma – This form affects individuals who have had an organ transplant on immunosuppressant drugs²
4. Endemic Kaposi’s sarcoma – This form is typically seen in African men or children²

Treatment for Kaposi’s sarcoma

Treatment of Kaposi’s sarcoma depends on the type of disease and its severity as well as the individual's overall health.

The primary methods of treatment for Kaposi’s sarcoma are:

• Antiretroviral Therapy
• Chemotherapy
• Radiation Therapy

What is antiretroviral therapy?

Antiretroviral therapy (ART) is a method of treatment used for Kaposi’s sarcoma.³ It is when a combination of several different drugs are used to decrease the damage caused to the immune system by an HIV infection.³

ART works by suppressing the effects of HIV on the immune system, allowing it to recover and strengthen, which will give the immune system better control of infections and virus-associated cancers such as Kaposi’s sarcoma and improve individual health.^3,4

Some studies have shown that ART can lead to a significant decrease in cancer and in some cases, even lead to the disease's regression, in combination with a restored immune system.⁵

Can ART be used on all Kaposi’s sarcoma severities?

ART is generally used on individuals who are not at high-risk, meaning their immune systems are still working well, and the Kaposi’s sarcoma has not spread widely.⁴

An indication of a well-working immune system is the levels of CD4, which are cells that help fight infection.⁴ If the levels of CD4 cells are low, then the immune system is not working very well against infection and vice versa.⁴

Individuals with high-risk Kaposi’s sarcoma, where the immune system CD4 levels are low and the cancer is widely spread, may need to take ART in addition to other cancer cell-attacking medications.⁴

Limitations of ART

Though ART is highly effective, it is not always sufficient as a treatment on its own, particularly for more severe/high-risk cases of Kaposi’s sarcoma.⁴

The effectiveness of ART can also vary in different parts of the world.⁶ For example, ART is not as effective in treating Kaposi’s sarcoma in Africa, and it is unclear why this is the case.⁵

What is chemotherapy?

Chemotherapy is the use of drugs to treat cancer.⁶ Chemotherapy is typically used for more advanced cases of Kaposi’s sarcoma, when the lesions/tumours have spread or are not responding to ART.^4,6

Common types of chemotherapy used for Kaposi’s sarcoma:³

• Systemic chemotherapy: Liposomal doxorubicin and Paclitaxel
• Electrochemotherapy

Systemic chemotherapy

Systemic chemotherapy is most commonly used to treat Kaposi’s sarcoma, which is when the drugs are given by injection into the vein or by mouth, allowing them to enter the bloodstream and reach almost all areas of the body.^3,6  

Liposomal doxorubicin

A type of systemic chemotherapy called liposomal chemotherapy is when tiny fat particles called liposomes are used to carry anticancer drugs and are better taken up by the tumour.^3,6 Liposomal doxorubicin is a drug that slowly releases doxorubicin into the tumour, leading to a decrease in healthy tissue damage.^3,6

Paclitaxel

Paclitaxel is another drug commonly used for Kaposi’s sarcoma, and studies have shown it seems to work just as well as doxorubicin.⁶

Electrochemotherapy

Electrochemotherapy is another type of chemotherapy which involves a probe that is used to send electrical impulses to the tumour, which makes an opening in the cell membrane around the tumour cell, allowing the chemotherapeutic drugs to get in.^3,6 This can be used for tumours on the skin.³

Side effects of chemotherapy

Chemotherapy attacks cancer cells in the body, but also normal cells can be affected.⁶ This can lead to a variety of side effects including: nausea, mouth sores, hair loss, and fatigue.⁶

A lot of people with Kaposi’s sarcoma will improve with chemo. However, their cancer may not completely go away, as chemotherapy may need to be stopped earlier, as it can compromise immune system health, which is crucial, especially in those with this condition.⁶

Integration with ART

Chemotherapy can be given alongside ART to individuals with Kaposi’s sarcoma.⁷ This requires careful planning and the timing of the respective treatments to avoid overlapping of drugs, leading to toxic effects.⁷

What is radiation therapy?

Radiation treatment is a type of cancer treatment that uses high-energy X-rays or other types of radiation to kill cancer cells or stop them from growing.³

Though radiation does not treat the underlying HIV, it is excellent in relieving symptoms and improving individual quality of life.⁸

There are 2 main types of radiation therapy:

1. External radiation therapy - when a machine outside of the body is used to send radiation towards an area of the body with cancer³
2. Internal beam radiation therapy – uses a radioactive substance sealed in needles, wires, seeds, which are radioactive pellets or catheters that are placed directly at the site of the cancer or near it³

What type of radiation therapy is used depends on the type of cancer and individual needs.³

For lesions on the skin or near the surface of the body caused by Kaposi’s sarcoma, external beam radiation, a type of external radiation therapy, is most commonly used.⁸ The radiation is used to reduce symptoms like pain or swelling from the Kaposi’s sarcoma lesions.⁸ It can also be used for skin lesions that look ‘bad’ and can easily be seen (like on the face).⁸

Photon radiation is also another type of external radiation therapy used in Kaposi’s sarcoma, which is used to treat lesions in the mouth or throat, as this type of radiation can penetrate deeper into the body.⁸

Personalised medicine

Personalised medicine is the practice in which treatment is tailored to a specific individual. In the case of Kaposi’s sarcoma, individual treatment is crucial, as there are different types/severities of Kaposi’s sarcoma.

Factors such as the immune system integrity, the spread of the cancer, and side effects can play a role in how health professionals decide what treatments are most suitable for specific individuals.

Conclusion

Kaposi’s sarcoma is a rare type of cancer that is mostly known for its purplish tumours and its typical association with HIV and a weakened immune system. There are 3 main ways to treat Kaposi’s sarcoma, depending on the type: Antiretroviral therapy (ART), Chemotherapy, and Radiation therapy. The treatment chosen for a certain individual is dependent on factors including: the type of cancer and its severity, as well as the immune system integrity and how an individual responds to the treatments and their side effects.