Incidence of Kaposi Sarcoma in Sweden is Decreasing
Giedre Bieliauskiene, Oscar Zaar, Isabel Kolmodin, Martin Gillstedt, John Paoli
Kaposi sarcoma is a rare skin cancer, and epidemiological research into Kaposi sarcoma is therefore scarce. The current epidemiological situation for Kaposi sarcoma in Sweden is unknown. The authors hypothesized that the incidence of Kaposi sarcoma should have decreased after the introduction of antiretroviral therapy in 1996. Using data from the Swedish Cancer Registry, this study aimed to determine the incidence rates and survival for Kaposi sarcoma in Sweden from 1993 to 2016. The results showed that a total of 657 patients (74.0% men, 26.0% women) were diagnosed with Kaposi sarcoma in Sweden during 1993 to 2016. The overall incidence per 100,000, age-standardized to the world population, decreased from 0.40 to 0.10 (p = 0.003) for both sexes combined, from 0.76 to 0.14 (p=0.003) for men, and from 0.07 to 0.06 (p = 0.86) for women. The 10-year overall survival rate was significantly lower for the study population (30%) compared with the age- and sex-matched Swedish population (56%) (p < 0.00001). Over the study period, incidence rates of Kaposi sarcoma decreased significantly in men, especially during the late 1990s.
This study shows that Kaposi sarcoma is an uncommon cancer in Sweden and that incidence rates decreased significantly in men, especially, during the late 1990s coinciding with the introduction of antiretroviral therapy. In general, Kaposi sarcoma is more common among men, and primarily affects the lower extremities and people above the age of 70 years in Sweden. Our results support the theory that the most common subtypes of Kaposi sarcoma in Sweden today are classic and/or immunosuppression-related Kaposi sarcoma. There is also a significantly lower survival rate among Swedish patients with Kaposi sarcoma compared with the age-matched Swedish population.