Kaposi sarcomacancer arising from bones and/or soft tissue (KS) is a rare type of sarcoma that develops in the lining of bloodthe red bodily fluid that transports oxygen and other nutrients around the body and lymph vesselsa network/chain of thin tubes that moves lymph fluid around the body. More specifically, it develops from endothelial cellsthe basic structural and functional unit of all living things, which are responsible for regulating inflammatory response and controlling the passage of certain substances from the blood into the tissues.
KS is always associated with an infectiona condition where harmful pathogens, such as bacteria, viruses or parasites, have entered the body with the human herpes virus 8 (HHV-8), which is also known as the Kaposi sarcoma-associated herpesvirus (KSHV). It is similar to the Epstein-Barr virus (EBV), which is also known as human herpes virus 4 (HHV-4), and is known to affect four distinct populations.
KS is slightly more common in men, and is frequently found in people with suppressed immune systems. However, anyone can develop this disease.
Types of Kaposi Sarcoma
There are four types of KS, which are categorised by the populations they affect.
Classic (Mediterranean) Kaposi Sarcoma
Classic KS generally affects older men of Mediterranean or middle/east European descent. This type may result from being a carrier of HHV-8 that has been activated by the natural age-related immune system decline. The classic subtype is often slow-growing, and generally appears as lesions on the legs, ankles and/or feet.
Epidemic (AIDS/HIV) Kaposi Sarcoma
Epidemic KS, also known as AIDS-related or HIV-associated Kaposi sarcoma, is the most common type of Kaposi sarcoma. This type develops in patients who have been diagnosed with the human immunodeficiency virus (HIV) and/or acquired immunodeficiency syndrome (AIDS). It is frequently found in men who engage in sexual intercourse with other men. It may also be found in children, as a possible result of saliva transmission from parent to child.
Endemic (African) Kaposi Sarcoma
Endemic KS is frequently found in equatorial Africa (countries along the equator in Africa). This type is often found in children and young adults, and may be linked to saliva transmission from parent to child. Common health concerns in some African populations, such as malaria, certain chronica long-lasting disease that changes slowly over time infections, and malnutrition, may contribute to the development of this disease.
Iatrogenic (transplant-related) Kaposi Sarcoma
Iatrogenic KS is most commonly found in patients who take immune-supressing drugs after an organ transplanta surgical procedure that involves removing a failing or damaged organ and replacing it with a healthy one from a donor to decrease the riskthe possibility that something bad will happen of organ rejection. This type tends to be a milder form than other types of KS, and is usually easier to manage.
Treatment
If KS is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumoura tissue mass that forms from groups of unhealthy cells) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissuea group of cells that work together to perform a function.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including type of KS, location, stage of disease and overall health.
Classic Kaposi Sarcoma Treatment
Classic KS is usually low-grade and slowly metastasises (if it does at all). As such, the treatment options for this type usually include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, potentially including:
- Tumour excisionto surgically remove/cut out.
- Curettage and electrodesiccationa procedure where the cancer is scraped out with a small, sharp instrument (curette), followed by the application of low-level heat to stop bleeding and kill any remaining cancer cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Cryotherapythe process of freezing off cancerous tumours and/or lesions using liquid nitrogen.
- Photodynamic therapya procedure that involves inserting a light-sensitive drug (photosensitiser) to shrink and damage cancer cells when exposed to a light source.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
- Complementary therapiesa variety of practices and exercises used alongside conventional treatment methods that may improve wellbeing and sense of control (e.g. meditation, art therapy, yoga etc.).
Epidemic Kaposi Sarcoma Treatment
Epidemic KS can be treated in a few different ways, including:
- Anti-AIDs drug combinations, potentially including the highly active antiretroviral therapy drug (HAART).
- Radiation therapy.
- Cryotherapy.
- Photodynamic therapy.
- Chemotherapy.
- Clinical trials.
- Palliative care.
- Complementary therapies.
Endemic Kaposi Sarcoma Treatment
Treatments for Endemic KS are generally the same as classical treatment options. However, as this type of cancer is frequent in poorer countries, treatment options available may be limited. Treatment options may include:
- Surgery, potentially including:
- Tumour excision.
- Curettagea procedure where the cancer is scraped out with a small, sharp instrument (curette) and electrodesiccation.
- Chemotherapy.
- Radiation therapy.
- Cryotherapy.
- Photodynamic therapy.
- Clinical trials.
- Palliative care.
- Complimentary therapies.
Iatrogenic Kaposi Sarcoma Treatment
Patients with Iatrogenic KS may simply involve stopping or switching the immune-supressing drugs taken after their transplant, if possible to do so. Other treatment options may include:
- Surgery, potentially including:
- Tumour excision.
- Curettage and electrodesiccation.
- Radiation therapy.
- Cryotherapy.
- Photodynamic therapy.
Chemotherapy is not generally given to patients with Iatrogenic KS.
Risk factors
KS is caused by an infection with HHV-8, which is most common in men who have sexual intercourse with other men and/or individuals with a HIV infection. It is also associated with transmission via saliva or insect bites, genetic factors, hormonal factors and immunodeficiency.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
KS can develop externally or internally. Symptoms that may be indicative of external KS lesions include:
- Lesions on the skin, which can be described as:
- Purple, red or brown in colour.
- Flat (patches), slightly raised (plaques) or bumps (nodules)
- Often appearing on the lower extremities (legs, ankles, feet), but can also develop on the face, in the pelvic region or on other parts of the body.
- Lesions in the lower extremities accompanied by painful swelling of the legs, ankles and/or feet.
KS lesions can also develop internally, in areas such as the mouth, throat, eye/eyelids, gastrointestinal tract and/or the lungs. Symptoms that may be indicative of internal KS lesions include:
- Lesions in the mouth, throat or eyelids that are not itchy or painful.
- Shortness of breath, caused by a lesion in the lung blocking an airway.
- Abdominal pain, caused by lesions in the stomach and/or intestinesportion of the digestive system that digests food (small intestine) and absorbs salts and water (large intestine), also called bowel.
- Diarrhoeafrequent discharge of watery or loose stools from the body.
- Coughing up blood, caused by bleeding lesions in the lung.
- Bloody stools, caused by bleeding lesions in the intestines.
- Anaemiaa condition where there aren't enough red blood cells in the blood, causing fatigue, weakness and pale skin and affecting how the body responds to infection.
- Fatiguea state of extreme tiredness or exhaustion, can be physical or mental.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis
If your doctor suspects you have KS, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- Chest x-raya type of medical imaging that uses x-ray beams to create detailed images of the body .
- Endoscopic ultrasoundan ultrasound taken during an endoscopy.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Faecal occult blood test (FOBT)a test used to determine if there is any trace of blood present in faeces or stool.
- Endoscopya procedure that involves inserting a long, flexible tube with a light and small camera (endoscope) into the body to view internal organs, potentially including:
- Bronchoscopyan examination of the trachea and lungs with a small, flexible instrument known as a bronchoscope.
- Gastroscopyexamination of the stomach and part of the small bowel with a small, flexible instrument known as a gastroscope.
- Colonoscopyan examination of the large intestine/bowel with a small, flexible instrument known as a colonoscope.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
