All About Kaposi's Sarcoma
What is Kaposi's sarcoma?
Kaposi's sarcoma (KS) is a cancer that develops from the cells lining the blood vessels and the lymphatic system. It usually presents as tumors that appear on the skin or inside the mouth but can develop in the lymph nodes, lungs, or digestive tract. Kaposi's sarcoma first became recognized as an AIDS-defining illness prior to the use of modern medications to control HIV (Human Immunodeficiency Virus). Much more has been learned about Kaposi's sarcoma through research over the years since it first appeared. For example, in 1994, it was discovered that infection with the human herpes virus 8 (HHV-8) was responsible for Kaposi's sarcoma. Although it is necessary to be infected with HHV-8 in order to develop KS, the vast majority of people with HHV-8 infection will never develop the disease. This is because our immune systems work to control the virus and keep it from causing tumors.
Kaposi's sarcoma is classified according to the clinical circumstances in which it arises. The four types of Kaposi's sarcoma are as follows:
This is the first type of Kaposi's sarcoma. Classic Kaposi's sarcoma (CKS) typically presents in middle-aged or elderly patients. Although it can be seen in other parts of the world, it is characteristically seen in individuals from the Mediterranean region, Middle East, or Eastern Europe. CKS presents more commonly in men, and the lesions commonly appear on the lower extremities and feet (soles and toes) as red, purple, or deep blue patches that grow and come to form larger plaques. Infection with HHV-8 is more common in these regions and is likely the cause of CKS cases in these populations. It has been suggested that as these individuals get older, their immune systems weaken, and Kaposi's sarcoma lesions develop. Because individuals with CKS generally have stronger immune systems than those with other types of Kaposi's, the CKS lesions generally develop slower and spread less quickly.
Epidemic (AIDS-related) Kaposi's sarcoma
This subtype of Kaposi's sarcoma is the most common and was first described during the 1980s when the AIDS epidemic reached its pinnacle, prior to discovery of HAART (highly active antiretroviral therapy). When an individual is infected with HIV, they do not develop AIDS until the virus has damaged his/her immune system to the point that it is not functioning well (if at all). As one's immune system is weakened, infections that are controlled by a healthy immune system can develop; these are called opportunistic infections. It is thought that HHV-8 is sexually transmitted in this population in a manner similar to the HIV virus. Since the introduction of HAART, the incidence of KS has dramatically declined in the HIV-infected population.
When the immune system is weak, the HHV-8 virus is much more likely to lead to the development of Kaposi's sarcoma. Because of this, Kaposi's sarcoma was one of the first AIDS-defining illnesses. The lesions associated with AIDS tend to be very different than other forms of KS. These lesions tend to be found on the head, neck, chest, and back, but can also be found in mucous membranes, such as in the GI tract (stomach and intestines) and the lungs. AIDS-related KS is often more aggressive, with many more lesions that progress more quickly than other types.
Iatrogenic (Transplant-related) Kaposi's sarcoma
Following the transplant of an organ from a donor into a recipient, the transplant recipient must take medications to suppress their immune system to protect the new organ from being attacked by his/her immune system. Kaposi's sarcoma arises in this instance when the transplant recipient harbors the HHV-8 virus or when the transplanted organ is infected with the virus prior to the transplant. After the transplant, suppression of the immune system is critical in maintaining a functional organ, however, this allows the HHV-8 virus to develop KS lesions. Generally, decreasing the immune-suppressing medications can control transplant-related KS. The lesions of transplant-related KS tend to be much less aggressive than AIDS-related KS.
Endemic (African-related) Kaposi's sarcoma
This subtype of KS characteristically occurs in people living in Equatorial Africa. People living in Africa tend to have compromised immune systems related to malaria, chronic infections, and malnutrition which may contribute to the development of KS in a more broad age range than other types of KS. Endemic KS most commonly occurs in people younger than 40 years of age. There is a rare, but more aggressive form of endemic KS seen in children, which affects the lymph nodes and organs, and tends to progress rapidly.
What causes Kaposi’s sarcoma and am I at risk?
HHV-8 infection, which is also referred to as Kaposi’s sarcoma associated herpes virus (KSHV), is required to develop KS. However, HHV-8 is not commonly tested for, and the vast majority of individuals with HHV-8 are not aware that they are infected, nor will they ever develop KS. In the United States, less than 10% of the population has HHV-8. It is more common in those with HIV and more common in men who have sex with men than in men who only have sex with women. KS has become less common in the United States now that AIDS is better managed with medications and therefore people infected with AIDS immune systems are not as weak. There are about 6 cases per million people each year and its more common in men than women. It is more common in African Americans than in whites. About 1 in 200 organ transplant recipients develop KS in the United States each year.
Please refer to the above sections for what causes each type of Kaposi’s sarcoma.
How can I prevent Kaposi’s sarcoma?
Kaposi sarcoma is caused by the HHV-8 infection. There are no vaccines to protect against it at this point. Preventing the transmission of HHV-8 is the best way to prevent KS. Most cases of KS in the United States is in people who have AIDS. To prevent the transmission of HIV and HHV-8 it is important to practice safe sex through the use of condoms. People who inject recreational drugs should stop, or at least use clean needles and injection supplies. HIV-infected mothers can pass the virus to her baby. Both the mother and baby should be treated with anti-HIV medications. For those who are already infected with HIV and HHV 8, medications to strengthen the immune system can be given, which include highly active antiretroviral therapy (HAART). These medications, along with the prompt treatment of infections can reduce the likelihood of developing KS.
What screening tests are used for Kaposi’s sarcoma?
There are no recommended screening tests to monitor for KS in people who are not at risk for the disease. However, since those infected with HIV are at a higher risk for developing KS, they should be examined regularly by health care providers who are experienced in recognizing KS and other diseases associated with HIV and AIDS.
What are the signs of Kaposi's sarcoma?
Kaposi's sarcoma is characterized by the development of red, purple, or deep blue lesions most often found on the skin and mucosa. The lesions are not painful, generally do not itch and typically have their colored appearance due to blood vessels within the lesions. As noted above, classic KS and endemic KS are commonly seen on the lower extremities. AIDS-related KS and iatrogenic KS can be seen on mucosa-lined surfaces (i.e. GI and respiratory tract) as well on inner organs (i.e. lungs).
KS lesions typically start as small flat lesions that can range in size from millimeters to several centimeters. These lesions are known as macules, which can remain unchanged for years in classic KS. In rare cases, they will progress very rapidly. As the lesions grow, they will frequently coalesce, or grow together, forming larger lesions known as plaques. As the lesions continue to grow, they can form even larger lesions known as nodules. Nodular lesions can ulcerate and bleed if damaged. In the endemic form of KS, lesions can form as fluid-filled cysts due to invasion of lymphatic vessels.
Finally, in AIDS-related KS, the lesions can be seen on the lower extremities, the face, the genitalia, and in the mouth. The lesions have similar appearance as other forms of KS. However, the natural progression of AIDS-related KS tends to be much more rapid with nodules developing rather quickly. AIDS-related KS in the GI tract can present as lesions, with no symptoms, found on radiology studies for something else or can present with symptoms including weight loss, stomach pains, bleeding, or diarrhea. Lesions within the respiratory tract can also be asymptomatic. If symptoms develop, they can involve shortness of breath, cough, chest discomfort, or coughing up blood (hemoptysis).
How is Kaposi's sarcoma diagnosed?
The diagnosis of Kaposi's sarcoma is generally made on the appearance of the lesions and clinical setting in which they are discovered. The diagnosis may be confirmed with a skin biopsy. Either a tiny round piece of tissue will be removed through a procedure called a punch biopsy or the entire lesion is removed, which is called an excisional biopsy. Both can be performed with local anesthesia in your provider’s office. Though a lesion may appear to be KS, it could be other diagnoses such as angiosarcoma, hemangiomas and bacterial infections (i.e. Bartonella). These possible alternative diagnoses are referred to as "differential diagnoses" and you may hear the medical team say they need to rule out differential diagnoses.
For individuals with immunosuppression and symptoms, GI tract involvement can be confirmed with an upper or lower endoscope. Respiratory involvement may be identified with chest X-Ray or CT scan but may require bronchoscopy to get a biopsy to confirm the diagnosis.
How is Kaposi's sarcoma staged?
Because KS does not develop like other cancers it is not staged like a typical cancer and there is no officially accepted system. For AIDS-related KS the AIDS Clinical Trials Group (ACTG) system is the most widely used staging system. The ACTG considers three factors in this staging system: the extent of the tumor (T), the status of the immune system measured by the CD4 cell count and the extent of involvement within this body know as system illness (S). Within each heading, there are also 2 subgroups, which are either 0 (good risk), or 1 (poor risk). It also takes into account the Karnofsky Performance Status scale. This is a measurement of a cancer patient's ability to perform daily tasks.
Good Risk - 0
Poor Risk - 1
(Any of the following)
(Any of the following)
Confined to skin and/or lymph nosed and/or minimal oral disease.
Immune System (I)
CD4 cell count is 200 or more cells per cubic mm.
CD4 cell count is lower than 200 cells per cubic mm.
Systemic Illness (S)
How is Kaposi's sarcoma treated?
Because there is no cure for HHV-8, there is no cure for Kaposi's sarcoma. However, the disease can frequently be controlled with treatment. The primary objectives when treating Kaposi's sarcoma are to improve the patient's symptoms and prevent progression to more aggressive lesions. Due to the rare nature of classic KS, there is no consensus on what is the best treatment. Generally, the treatment is based on the experiences of the treating provider, patient preference and the clinical picture (i.e. AIDS-related, classic KS in elderly man, etc.).
Treatments for Classic and Endemic KS
For classic and endemic KS, surgery, radiation therapy and topical therapies are available. In lesions that are limited and causing no symptoms, observation may be the best option, avoiding treatment related toxicities. For patients with symptomatic lesions, surgical excision of a single lesion can be beneficial; however, additional lesions often develop, limiting the effectiveness of this treatment. Radiation therapy, which uses high energy x-rays to damage the DNA of cells, thereby killing the cancer cells, or at least stopping them from reproducing, is particularly effective for all forms of KS. Although recurrences out of the treatment field often occur and limit its use. The use of cryotherapy in which liquid nitrogen is used to freeze and kill the cancer cells resolves most lesions but can cause blistering and pain. Laser ablation is used on lesions on the face and oral cavity.
Chemotherapy may be injected directly into the lesions. The most commonly used chemotherapy for direct injection are vinlblastine. Cis-retinoic acid and imiquimod are topical creams that can be applied directly to the lesion to inhibit cell growth. These medications can be applied by the patient, but tend to be costly and can cause skin reactions. Unfortunately, these are "local treatments" which work in a small area and do not deal with the multifocal (system-wide) nature of KS.
Several systemic therapies have also been used in treatment of aggressive and advanced classic KS. Indications for chemotherapy include rapidly progressive classic KS that interferes with function and is severely symptomatic. Chemotherapy is a systemic medication meaning that it can treat the entire body. Your provider will determine the most appropriate medications and regimen for you. The most commonly used systemic chemotherapies used are gemcitabine, doxorubicin, daunorubicin and paclitaxel. Finally, treatment with immunomodulators, such as interferon, has shown effectiveness but is not often used due to its side effects. There have been no randomized clinical trials demonstrating the optimal agent or duration of treatment to control aggressive, systemic classic KS.
Immunosuppression Related KS Treatment
In cases of KS related to immunosuppression, improvement in immune function and treatment of the cause can often lead to stopping the progression of lesions. For individuals with AIDS-related KS, highly active antiretroviral (HAART) is recommended. HAART has proven very effective in the prevention of KS as it improves CD4 counts as well as keeping the viral load low (amount of virus found in the blood). When KS is caused by intentional immunosuppression, as in the case of an organ transplant, a decrease in the level of immune suppression is recommended.
Local therapy is generally reserved for symptomatic lesions and palliation. Similar to classic KS, local therapies include radiation therapy, topical cis-retinoic acid, and intralesional chemotherapy. Prior to the use of HAART, radiation therapy was frequently used for locally advanced disease. Intralesional chemotherapy, chemotherapy that is injected directly into the lesion, is generally only used in smaller lesions.
The use of systemic treatments, specifically chemotherapy, is only used in patients with disseminated or rapidly progressive KS. Indications for chemotherapy include widespread skin lesions, edema (swelling) associated with extensive lesions, symptomatic lesions on internal organs, skin lesions that fail to respond to local treatments, and immune reconstitution inflammatory syndrome. Immune reconstitution inflammatory syndrome refers to an acute worsening of KS that can occur within weeks of the initial introduction of HAART.
There are clinical research trials for most types of cancer, and every stage of the disease. Clinical trials are designed to determine the value of specific treatments. Trials are often designed to treat a certain stage of cancer, either as the first form of treatment offered, or as an option for treatment after other treatments have failed to work. They can be used to evaluate medications or treatments to prevent cancer, detect it earlier, or help manage side effects. Clinical trials are extremely important in furthering our knowledge of this disease. It is through clinical trials that we know what we do today, and many exciting new therapies are currently being tested. Talk to your provider about participating in clinical trials in your area. You can also explore currently open clinical trials using the OncoLink Clinical Trials Matching Service.
Follow-Up Care and Survivorship
Survivors of Kaposi’s sarcoma require lifelong monitoring and survivorship care because in some cases the treatment has not completely removed and destroyed the cancer. Your provider will watch you closely after treatment and during your visits your provider will determine how to monitor the disease and how, if necessary, to continue treatment. The treatment(s) you have already received can cause long-term side effects and you should report any new or recurrent symptoms to your care team immediately.
Fear of recurrence, financial impact of cancer treatment, employment issues, changes in appearance, and coping strategies are common emotional and practical issues experienced by Kaposi’s sarcoma survivors. Your healthcare team can identify resources for support and management of these practical and emotional challenges faced during and after cancer.
Cancer survivorship is a relatively new focus of oncology care. With nearly 17 million cancer survivors in the US alone, there is a need to help patients transition from active treatment to survivorship. What happens next, how do you get back to normal, what should you know and do to live healthy going forward? A survivorship care plan can be a first step in educating yourself about navigating life after cancer and helping you communicate knowledgeably with your healthcare providers. Create a survivorship care plan today on OncoLink.
Resources for More Information
American Cancer Society
Information and support services available for patients and family members.
This website, started by a sarcoma survivor, is based on the mantra "guidance, education, and support". They also maintain a list of specialty centers.
Sarcoma Foundation of America
The SFA raises money for sarcoma research and aims to raise awareness of sarcoma. The site has information for patients as well.
American Cancer Society, Detailed Guide: Kaposi's sarcoma. 2018.
American Society of Clinical Oncology. Sarcoma-Kaposi: Stages. 2019.
Fatahzadeh, M. Kaposi sarcoma: review and medical management update. Medical Management and Pharmacology Update.2012. 113(1):2-16.
National Institute of Health. National Cancer Institute. Kaposi Sarcoma. https://www.cancer.gov/types/soft-tissue-sarcoma/patient/kaposi-treatment-pdq
Radu O and Pantanowitz L. Kaposi Sarcoma. Archives of Pathology and Laboratory Medicine. 2013. 137(2):289-294.
Ruocco E et al. Kaposi’s sarcoma: Etiology and pathogenesis, inducing factors, casual associations, and treatments: Facts and controversies. Clinics in Dermatology. 2013. 31:413-422.