Ecological study of gastric cancer in Brazil: geographic and time trend analysis.

Aim: To investigate the geographic distributions and time trends of gastric cancer (GC) incidence and mortality in Brazil.

Methods: An ecological study of the DATASUS registry was conducted by identifying hospitalizations for GC between January 2005 and December 2010. The data included information on the gender, age, and town of residence at the time of hospital admission and death.

Results: The GC rates, adjusted according to available hospital beds, decreased from 13.8 per 100000 in 2005 to 12.7 per 100000 in 2010. The GC rates decreased more among the younger age groups, in which the male-to-female difference also decreased in comparison to the older age groups. Although the lethality rates tended to increase with age, young patients were proportionally more affected. The spatial GC distribution showed that the rates were higher in the south and southeast. However, while the rates decreased in the central-west and south, they increased in the northern regions. A geographic analysis showed higher rates of GC in more urbanized areas, with a coast-to-inland gradient. Geographically, GC lethality overlapped greatly with the hospital admission rates.

Conclusion: The results of this study support the hypothesis of a critical role for environmental factors in GC pathogenesis. The declining rates in young patients, particularly males, suggest a relatively recent decrease in the exposure to risk factors associated with GC. The spatial distribution of GC indicates an ongoing dynamic change within the Brazilian environment.