[Incidence and mortality from thyroid cancer in Brazil]

Abstract

In this study we evaluated the incidence and mortality due to thyroid cancer (TC) in Brazil using incidence data provided by seven Brazilian cancer registries and mortality data from the Brazilian Mortality Information System. Five-year age-adjusted mortality rates were calculated over a 20-year period (1980-1999) for the country as a whole. We have calculated a 3-year age-adjusted incidence rate using data available since 1993. Age-adjusted mortality rates decreased from 0.22/100,000 to 0.28/100,000 (-21%) among males, and from 0.42/100,000 to 0.51/100,000 (-17%) among females. Among males, age-adjusted incidence rates varied from 0.7/100,000 in Belém to 3.0/100,000 in São Paulo. These cities also presented the lowest (0.8/100,000) and the highest (10.9/100,000) age-adjusted incidence rates among females. The downward tendency of mortality is probably explained by an improvement in diagnosis and treatment of TC over the study period, whereas geographical variations in incidence are probably related to availability of medical care resources in the different regions and the quality of cancer registers data.