Thyroid cancer burden in Central and South America

- Thyroid cancer incidence and mortality rates varied by 8-12 fold and 2-6-fold, respectively.
- Females had 4-6 times higher incidence rates and 1-3 times higher mortality rates than males.
- Papillary thyroid carcinoma is the most frequent histological type diagnosed in females and males.
- Incidence of thyroid cancer is increasing rapidly in Argentina, Brazil, Chile and Costa Rica.

Rationale and objectiveIncidence of thyroid cancer (TC) is rapidly increasing worldwide, but little is known about the TC burden in Central and South America (CSA). We describe the geographic patterns and trends of TC by sex in CSA.MethodsWe obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries and nationwide cancer deaths from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence rates (ASRs) and age-standardized mortality rates (ASMRs) per 100,000 person-years. We calculated ASRs by histological subtype. We estimated the annual percentage change (EAPC) to describe time trends.ResultsBetween CSA countries, TC incidence and mortality rates varied from 8-fold to 12-fold and from 2-fold to 5-fold, respectively. In 2003-2007, the highest TC ASRs in females and males were in Ecuador (16.0 and 3.5, respectively), Brazil (14.4 and 3.4), Costa Rica (12.6 and 2.1) and Colombia (10.7 and 2.5). The highest ASMRs were in Ecuador, Colombia, Mexico, Peru and Panama (0.68-0.91 in females and 0.41-0.48 in males). Papillary TC was the most commonly diagnosed histological subtype, following the same incidence pattern as overall TC. In Argentinean, Brazilian, Chilean and Costa Rican females TC incidence increased by 2.2-17.9% annually, and papillary TC increased by 9.1-15.0% annually, while mortality remained stable between 1997 and 2008. In males, trends in TC were stable.ConclusionTC occurred more frequently in females than in males. The overall high incidence and low mortality of TC suggest identification of subclinical disease due to improved detection methods.