Geographical mapping of gastrointestinal cancer mortality rates in Mazandaran and Golestan provinces, Iran

Background and Cancer is the third leading cause of death in Iran. Mazandaran and Golestan provinces, especially in northern countries, have a high incidence of gastrointestinal cancer. Therefore, we aimed to find the geographic distribution of standardized mortality rates of this disease and to mark differences between the cities on a map. The data related to the cases of death from gastrointestinal cancer during the years 2001 to 2005 were recorded in the provinces of Golestan and Mazandaran. Generalized Poisson regression model was used for data standardization; then, the mapping was done. 5715 people died from cancer of the gastrointestinal tract, 65.18 percent in Mazandaran and 34.82 percent in Golestan. Standardized mortality rates in the central parts of the provinces showed a little less. From the city of Chaloos to the border of the city of Gorgan, standardized mortality ratio (SMR) of most of the regions was between 0.9 and 1. From the border of the city of Gorgan to end of eastern geographical boundaries of Golestan Province, the obtained standardized mortality ratio was more than 1. The regression model could partly eliminate heterogeneity of standardized mortality ratio. Changes in mortality rates from cancers of the gastrointestinal tract in Mazandaran and Golestan provinces on the map represent a high-risk area, which remarks the impact of geographical and social-economic region.