By Dr Ananya Mandal, MD
Kaposi's sarcoma is a form of cancer that affects people with decreased immunity. It is seen in patients with HIV infection, elderly men of Mediterranean, Jewish or African descent and patients taking drugs for suppression of immunity after organ transplantation.
Kaposi's sarcoma and AIDS
The rise of number of cases of Kaposi's sarcoma occurred in the 1980s and 1990s as the number of AIDS cases soared.
After the advent of anti HIV drugs called the highly active antiretroviral therapy (HAART) the incidence of Kaposi's sarcoma has reduced. However Kaposi's sarcoma remains a commonly reported cancer in some African countries commonly due to untreated HIV infection.
Causes of Kaposi's sarcoma
Causes of Kaposi's sarcoma include (1-4):
- Endemic or African Kaposi's sarcoma affects young adult men in equatorial Africa with a normal immune system. Up to 9% of Ugandan men suffer from this condition. Sometimes children may be affected as well.
In them the cancer invades the lymph nodes and lymphatic channels and spares the skin. This is usually associated with spread to other organs may be fatal.
- Transplant-related or acquired Kaposi's sarcoma. Patients after an organ transplant need immunity suppressing drugs. This prevents the patient’s immunity from attacking and killing the newly transplanted organ. These patients on immunity suppressing drugs are at risk of Kaposi's sarcoma.
- Epidemic or HIV associated Kaposi's sarcoma. This is the commonest cause of Kaposi's sarcoma.
- Kaposi's sarcoma-associated herpes virus (KSHV) or Human herpes virus 8 (HH8) is a common infection that can lead to Kaposi's sarcoma. KSHV belongs to the herpes virus family.
This virus is similar to Epstein-Barr virus. The EB virus causes infectious mononucleosis or glandular fever and contributes to several types of cancer like lymphomas.
The KSHV brings in genetic material into the cells. These altered genes cause the cells to divide too much and unnecessarily leading to cancer. HHV-8 does not cause Kaposi's sarcoma in everyone who develops the virus. The virus only seems to cause Kaposi’s sarcoma in people with a high risk.
Risk factors of getting Kaposi's sarcoma
Risk factors of getting Kaposi's sarcoma include (1-4):
- Men are more commonly affected. In African countries male patients who are not HIV positive are more frequently affected with the virus than females.
- Men of the Mediterranean, Middle Eastern or African origin and of Ashkenazi Jewish descent are more at risk. This could be due to an inherited vulnerability to HH8 virus.
- Men who have sex with men are more at risk. Homosexual as well as heterosexual partners of Kaposi's sarcoma patients are at risk of HH8 infection.
- Those with a suppressed immunity with HIV AIDS infection are at a greater risk of Kaposi's sarcoma.
- Those with diabetes and on oral corticosteroid medications are at risk. These conditions lead to decrease in immunity and thus may lead to the predisposition.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)