What is AIDS-related (epidemic) Kaposi sarcoma (KS)?

Updated: Apr 11, 2019
  • Author: Jessica Katz, MD, PhD, FACP; Chief Editor: Edwin Choy, MD, PhD  more...
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This entity occurs in patients with advanced HIV infection and is the most common presentation of Kaposi sarcoma. It is an AIDS-defining cancer, and is approximately 500 times more common in HIV-infected patients than the general US population. Kaposi sarcoma accounts for 12% of cancers in people living with HIV, with 765 to 910 new cases per year in the US. [7, 8, 9]

Decreased CD4 counts and increased HIV-1 viral loads are independent prognostic factors in the development of epidemic Kaposi sarcoma.  The disease usually develops in HIV-infected patients with severe immunodeficiency; less than one sixth of HIV-infected patients with Kaposi sarcoma have CD4 counts of over 500 cells per microliter. Immune reconstitution during the first 3 months of HAART may contribute to the risk for AIDS-defining Kaposi sarcoma. [19]

Kaposi sarcoma is a frequent complication of AIDS in men who have sex with men (MSM). A cross-sectional analysis of factors affecting risk in 99 cases among 503 HHV-8 seropositive MSM with AIDS found that Kaposi sarcoma was [20] :

  • Significantly less common in blacks than in whites (risk ratio [RR] = 0.4; 95% confidence index [CI] = 0.2-0.8).
  • More common in subjects who had completed college (RR = 1.7; 95% CI = 1.1-2.7) or had annual income greater than $30,000 (RR = 1.5; 95% CI = 1.1-2.2).
  • Less common in cigarette smokers (RR = 0.6; 95% CI = 0.5-0.9) and users of crack cocaine (RR = 0.4; 95% CI = 0.1-0.8).
  • Less common in bisexual men than in men who were exclusively homosexual (estimated RR = 0.6; 95% CI = 0.4-0.9) and inversely associated with the number of female partners.
  • Less common in men who had received pay for sex (RR = 0.6; 95% CI = 0.4-1.0). 

Cigarette smoking may be protective for Kaposi sarcoma risk in HHV-8–seropositive patients infected with HIV, and relative affluence may increase the risk of Kaposi sarcoma in HIV-positive patients.The incidence of HHV-8 infection is higher in homosexual men than in drug users. [21, 20]

The presence of HHV-8 antibodies in HIV-infected persons increases the risk of Kaposi sarcoma. Among HIV-infected persons, those who subsequently seroconvert for HHV-8 are at highest risk. A comparison of 69 men who became infected with HHV-8 after acquiring HIV-1 with 182 men who were HHV-8 seropositive before their HIV-1 infection found that the risk of developing Kaposi sarcoma was higher in those whose HHV-8 seroconversion followed acquisiiton of  HIV-1 infection (risk ratio, 2.55; 95% confidence interval, 1.06–6.10). [21, 22]

Risk for Kaposi sarcoma in HHV-8-infected men increased by 60% (P< 0.001) for each year of HIV-1 infection. Faster CD4 cell loss and higher HIV-1 RNA levels significantly predicted Kaposi sarcoma. The quicker development of KS in men acquiring HHV-8 after HIV-1 and its association with CD4 slope argues that Kaposi sarcoma is more likely if HHV-8 infection occurs in an immunocompromised person. [21, 22]

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