By Dr Ananya Mandal, MD
The trillions of the cells in the body grow normally, divide, and then die accordingly. Once adulthood is reached cells divide only to replace worn-out or dying cells or to repair injuries.
What happens to cells in cancer?
Cancer starts when cells in a certain organ or part of the start to grow out of control. Cells become cancer cells because of damage to DNA.
Different types of cancer can behave very differently – some may remain at one location while others spread rapidly to other major organs via blood stream or via lymphatic channels. (1-4)
How does Kaposi's sarcoma develop?
Kaposi's sarcoma is a cancer that develops from the cell lining the lymph or blood vessels. The cancer appears as red, purple, or brown raised tumors or spots over the skin.
These lesions are usually non-symptomatic but may cause painful swelling in some areas like legs, groin or skin around the eyes.
Kaposi's sarcoma may become life threatening when it affects major organ like lungs, liver, or the gastrointestinal tract. In the gastrointestinal tract it may lead to bleeding while in the lungs it may lead to severe difficulty in breathing.
Who discovered Kaposi's sarcoma?
Kaposi's sarcoma was first described by Moritz Kaposi, a Hungarian dermatologist in 1872. (2)
Who is at risk of Kaposi's sarcoma?
An HIV-infected person has a 20,000 times increased risk of developing Kaposi's sarcoma to a person without HIV. In the early 1990’s there were approximately 47 cases per million people per year among the HIV infected individuals of United States.
With the advent of anti-HIV drugs the numbers have fallen and it now occurs at a rate of about 7 cases per million people each year.
The rates are highest in Africa where Kaposi's sarcoma herpesvirus (KSHV) (also known as human herpesvirus type 8 - HHV-8) and HIV infection rates are high. About 1 in 200 transplant patients in the United States gets Kaposi's sarcoma. (1-4)
Type of Kaposi's sarcoma
The major types of Kaposi's sarcoma are (1-4):
- AIDS-related or Epidemic Kaposi's sarcoma – This is the commonest type of KS in the United States. It affects patients infected with HIV. An HIV positive patient may harbor the virus in his or her body for years before getting AIDS. AIDS begins when the virus has severely debilitated the immune system. This damage to immune system leads to infections and complications like Kaposi's sarcoma. The CD4 count in blood is a measure of the effect of HIV on the immunity. The lower the CD4 count, the more likely that the patient will get Kaposi's sarcoma. Kaposi's sarcoma indicates that an HIV positive individual officially has AIDS and thus is called an “AIDS defining” illness.
- Classic Kaposi's sarcoma or Mediterranean Kaposi's sarcoma – This affects the elderly living in Mediterranean, Eastern European, and Middle Eastern regions for generations and the Ashkenazi Jews. It affects men more than women. 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. Lesions typically begin as one in the legs, ankles, or the soles of the feet. The lesions are usually slow to grow. The immune system of people with classic Kaposi's sarcoma is not as weak as it is in those who have epidemic Kaposi's sarcoma.
- Endemic Kaposi's sarcoma or African Kaposi's sarcoma – this affects people living in Equatorial Africa. These people are more at risk of developing infection with Kaposi's sarcoma Herpes Virus (KSHV). This form of Kaposi's sarcoma affects younger people under age 40. Rarely an aggressive form of the illness may be seen in children before puberty.
- Organ transplant-associated Kaposi's sarcoma – In individuals whose immune systems have been suppressed after an organ transplantation to prevent the body from rejecting the new organ, there is a risk of Kaposi's sarcoma. Most transplant patients need to immunosuppressant drugs to keep the immune system from attacking and killing the new organ that is perceived as a foreign object. If drugs weaken the immunity there is a risk of infection with KSHV and development of Kaposi's sarcoma.
- Kaposi's sarcoma in HIV negative men who have sex with men – this group is found to get mild cases of Kaposi's sarcoma similar to classic Kaposi's sarcoma.
Treatment of Kaposi's sarcoma
Kaposi's sarcoma can be treated using a combination of anti-HIV medication chemotherapy, radiotherapy and surgery.
Prognosis or outlook of Kaposi's sarcoma alone is good. Provided people with HIV-related Kaposi's sarcoma get access to anti HIV medication early on in their HIV disease, they can go into remission with regression of symptoms.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)