KYOTO, JAPAN — The incidence of Kaposi's sarcoma among American men jumped more than 30-fold in the 1980s with the AIDS epidemic, peaked around 1991, and then declined rapidly in concert with the introduction of highly active antiretroviral therapy, according to a study involving 12,114 cases of KS and other forms of cutaneous soft-tissue sarcoma.
This pattern held true for both white and black men. Whites led the rate increases during the 1980s, but Kaposi's sarcoma (KS) rates among black American men have exceeded those in white men since the mid-1990s. Only among men more than 70 years old, for whom the classic form of KS predominates, has the KS rate remained higher in whites, said Panta Rouhani of the University of Miami.
These were among the central findings of what she described as the first population-based study examining the epidemiology of KS in the United States during the last 3 decades. The study, conducted while she was at the National Cancer Institute, involved cases of KS and other forms of cutaneous soft-tissue sarcoma (CSTS) that were diagnosed from 1978 to 2004 in 13 NCI Surveillance, Epidemiology and End Results (SEER) registries.
CSTS is a heterogeneous collection of mesenchymal neoplasms accounting for less than 1% of malignant tumors. Their etiology and incidence are poorly understood. They are classified histologically according to 2002 World Health Organization criteria.
The incidence of CSTS was 24.4 cases per 1 million person-years. KS—by far the most common form of CSTS worldwide—accounted for 71% of cases, followed by dermatofibrosarcoma protuberans (18%), malignant fibrous histiocytoma (5.3%), leiomyosarcoma (2%), and angiosarcoma (1.6%), Ms. Rouhani said at an international investigative dermatology meeting.
All four types of KS are associated with human herpesvirus-8 infection: HIV-associated KS, endemic KS in patients from Central Africa, transplant-related KS, and the classic form of KS found predominantly in elderly individuals of Mediterranean ancestry.
The overall incidence of KS during the study years was 17 cases per 1 million person-years. The male:female ratio was 25.5:1 overall, but it started at 3:1 in 1978–1980, skyrocketed to 75:1 in the late 1980s, and fell to about 10:1 in the early 2000s. This striking male predominance involved both the HIV-related and classic forms of KS, Ms. Rouhani said at the meeting of the European Society for Dermatological Research, the Japanese Society for Investigative Dermatology, and the Society for Investigative Dermatology.
The dramatic rise of KS in the 1980s and its fall in the 1990s were observed not only in men aged 20–59 years but also in those aged 60–69. This older group is less commonly recognized as being at high risk for HIV-associated KS, although the SEER data demonstrate that indeed they are, she said.
The male:female ratio started at 3:1, skyrocketed to 75:1, and fell to about 10:1. MS. ROUHANI