Investigation of cancer incidence in ELSA-Brasil

Low- and middle-income countries have high cancer-related mortality rates, and Brazil has one of the highest incidences of all cancers in South America. Since 2008, the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) follows up 15,105 civil adult servants of college education and research institutions in six Brazilian capitals, collecting relevant information on risk factors for the incidence of cancer and other noncommunicable diseases. This study aimed to describe the methodology for surveillance and investigation of the incidence of primary cancers in ELSA-Brasil. The surveillance and investigation involve annual telephone interviews, data collection of medical registries (biopsy records, chemotherapy/radiotherapy reports, hospital records or death certificates/autopsy statements), eligibility and final classification, date and basis of diagnosis, tumor topography and histological type. The cumulative incidence of all types of cancer in ELSA-Brasil during the first five years of follow-up (2009-2013) was 2.27 %. The challenges encountered in the investigation process are related to the lack of data on the occurrence of distant metastasis and essential details regarding diagnoses. However, the quality control and the adequacy of the methods adopted enables the construction of a solid and pioneering database in the country, which will contribute to advance in research on the natural history of the most frequent types of cancer.