The incidence of Kaposi's sarcoma is increasing amongst Black South Africans and is a growing health problem that requires urgent attention, according to work published by the University of KwaZulu-Natal at the Fourth South African AIDS Conference in Durban.
Kaposi's sarcoma (KS) is a rare cancer that is much more common in people with immunosuppression, such as those with advanced HIV infection. The condition, which is characterized in its early stages by dark skin lesions and subsequently by lesions in the mucous membranes, the lungs, the gut and the lymph nodes, is caused by infection with human herpes virus 8 (HHV-8).
Despite the association between HIV infection and KS, there is still no well established incidence estimate for AIDS-associated KS in South Africa.
The current study, which attempted to estimate this incidence, made use of anonymous administrative records for patients receiving care for KS in KwaZulu-Natal between 1983 and 2006 in public-sector oncology clinics. Age-standardised incidence rates were calculated using provincial census data for the local population in the years of 1985, 1996, 2001 and 2005. Age-specific rates, which were subject to different data constraints, were assessed for the years 1983 to 1989 (the baseline) and for 2006 (the generalised HIV epidemic).
The researchers report that age-standardised incidence rates (per 100,000 people) increased from 1.04 to 19.7 between 1983 and 2007. This compares with a standardised incidence ratio in a Ugandan HIV-positive population of 6.7 when compared to the general population.
More worryingly, the incidence rate for women during the same period increased fifty-fold, from 0.21 to 11.51. Gender-averaged figures pointed towards an incidence increase from 0.52 to 14.76. Furthermore, the age of peak incidence (the age group in which KS is most likely to occur) was shown to shift from a 55 to 60-year age bracket to a 40 to 50-year age bracket for both men and women. This was expected because HIV is more prevalent in young people than old people.
The authors stress that only public-sector patients were considered in the study. Many cases of early and late stage KS may very well have been treated by private doctors or left untreated and, if this was a common occurrence, may very well have contributed to a serious underestimation of KS incidence.
The study illustrates the alarming growth of KS as a health problem in rural South Africa. The researchers call for more resources to be directed at quantifying the problem and for better medical resources to be made available for KS sufferers.
Our newsletter HIV & AIDS Treatment in Practice published a clinical review of Kaposi’s sarcoma management in resource-limited settings in February 2008.
Mosam Anisa et al. Increasing incidence of Kaposi’s sarcoma in Black South Africans in Kwazulu-natal, South Africa (1983 to 2006).. Fourth South African AIDS Conference, Durban, South Africa, abstract 52, 2009.
Mbulaiteye SM et al. Spectrum of cancers among HIV-infected persons in Africa: the Uganda AIDS-Cancer Registry Match Study. Int J Cancer;118(4):985-90, 2006.