Objective: To examine the influence of the AIDS epidemic on the incidence of Kaposi sarcoma (KS) and non-Hodgkin lymphoma (NHL) in Ontario.
Methods: Age-standardized incidence rates for KS and NHL from 1981 to 2000 were calculated from the population-based Ontario Cancer Registry. AIDS cases were extracted from Ontario Ministry of Health and Long-Term Care reports. HIV death data were obtained from the Ontario Cancer Registry.
Results: KS was a rare cancer before the 1980s; however, incidence increased sharply between 1985 and 1995 by 13.8% per year. Thereafter, incidence rates fell close to those in the early 1980s. NHL incidence in males increased steadily during the 1980s at 3.2% per year and then slowed beyond 1990. In males aged 30-44, NHL incidence rose from 1981 to 1990 (8.8% per year) and then fell (-2.5%) thereafter. NHL and KS cases represented one-third of HIV deaths.
Conclusions: The AIDS epidemic, the introduction of antiretroviral therapies, and the decrease in HIV infection rates explain the rise and decline of KS incidence in Ontario. NHL incidence trends are more complex, although the AIDS epidemic explains the trends observed in younger men (in whom AIDS is more common), and for the AIDS-related subtypes.