Kaposi's Sarcoma Health Article

Demographics

The demographic distribution of KS varies considerably across its five types:

• Classic KS. Classic KS is considered a rare disease, with a male/female ratio of 10:1 or 15:1. In North America and Europe, most patients are between 50 and 70 years old. Classic KS is more common in men from Mediterranean countries and in Ashkenazic Jews.
• African KS. African KS has the same male/female ratio as classic KS, although most patients with African KS are younger. A form of African KS that attacks the lymphatic system primarily affects children, with a male/female ratio of 3:1.
• Immunosuppresive treatment-related KS. This form of KS occurs mostly in kidney-transplant patients, at a rate of 150 to 200 times as often as in the general population. It represents 3% of all tumors that occur in kidney-transplant patients. The male/female ratio is 2:1.
• Epidemic KS. Epidemic KS is overwhelmingly a disease of adult homosexual or bisexual males. It is 20,000 times more common in people with AIDS than in those without HIV infection. According to the National Institutes of Health (NIH), 95% of all the cases of epidemic KS in the United States have been diagnosed in homosexual or bisexual males. Epidemic KS is far more prevalent among homosexual or bisexual males with AIDS than among hemophiliacs or intravenous drug users with AIDS. Prior to 1995, about 26% of all homosexual males with AIDS had KS as their first symptom or eventually developed KS, as compared with fewer than 3% of heterosexual intravenous drug users with AIDS. This clustering of KS cases among a subpopulation of AIDS patients led to the hypothesis that a blood factor transmitted by sexual contact is a partial cause of KS. The number of new cases of AIDS-related KS has declined in recent years, for reasons that are not yet clear. Some researchers think that the introduction of highly active antiretroviral therapy, or HAART, is related to the decline in the number of cases of epidemic KS. As of 2001, only about 12% of AIDS patients develop KS.
• Non-epidemic gay-related KS. This small group of KS patients is entirely male.