Abstract LB-390: Thyroid cancer incidence trends by gender and histology in Sao Paulo, Brazil, 1997-2005

Abstract

Abstract Thyroid cancer incidence has been increasing steadily in much of the developed world, but there is limited information on trends in the developing world. The overall rise in thyroid cancer incidence varies by gender, race/ethnicity, and geographic location, with the largest increases found among women and white non-Hispanics. Where histology is available, this increase has been accompanied by a change in the distribution of histological types, with a particular increase in papillary thyroid cancer. Sao Paulo, Brazil is the largest registry in Brazil and covers has one of the ten highest rates of thyroid cancer incidence worldwide, and has the highest rate among Brazilian registries. The Sao Paulo Registry covers about 15 million people in the region. Approximately 1000 new thyroid cancer cases are documented each year in Sao Paulo. This large number of cases presents the opportunity to evaluate trends in thyroid cancer incidence in a Latin American population. Using 12,495 cases reported between 1997 and 2005 to the Sao Paulo Cancer Registry, we analyzed thyroid cancer incidence patterns by gender and histology using Joinpoint analysis to calculate the annual percentage change (APC) in incidence, adjusting for age (standard world population). We found that females made up the vast majority of cases (87%) compared with males (13%). Papillary was the most common histology (74.7%), followed by follicular (17.3%), medullary (4%), and other (4%) among 77% of cases with histological confirmation. Overall incidence rates increased for both males and females, with a larger APC for females (+7.7%) compared with males (+6.6%). The greatest increases were seen for papillary and follicular histologies for both sexes. Rates increased most for females and males greater than 50 years of age compared with those 50 years or younger. Mortality rates remained relatively constant. These findings suggest that incidence rates of thyroid cancer are increasing in Sao Paulo, following a similar trend as seen in many developed countries. Further research looking at tumor stage and size could help to understand the potential causes of this increase. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-390.