[Reliability and accuracy of oral cancer as the reported underlying cause of death in the Municipality of Rio de Janeiro].

Mortality statistics are frequently employed in cancer epidemiology studies. The aim of this research was to evaluate the reliability and validity of oral cavity cancer as the underlying cause of death reported on death certificates in the Municipality of Rio de Janeiro, Brazil. All death certificates since 1999 reporting this underlying cause of death were selected from the Municipal Mortality Information System. The death certificates were re-coded by an independent technician, and a standardized questionnaire was designed to collect clinical and laboratory data for diagnostic confirmation from patient records. Histopathological results and/or clinical history were considered as the gold standard to establish the diagnosis of cancer of the mouth. Reliability analysis showed a simple percentage agreement of 95.1% and a kappa coefficient of 0.93. Positive predictive value was 86.5%. Mortality statistics for oral cancer in Rio de Janeiro Municipality demonstrate good reliability and validity, possibly because diagnostic confirmation is facilitated by easy access to the tumor site.