Geographical variability in cancer incidence explained by the socioeconomic environment: an example of lung cancer in northwestern France.

Background: The incidence of lung cancer is unequally distributed in France. Although several studies have shown a link between the socioeconomic environment of populations and the incidence of cancer, the contribution has not been quantified. We aimed to analyse the geographical variability of lung cancer incidence in Normandy and calculate the proportion explained by the socioeconomic environment.

Methods: We included 7665 lung cancer cases recorded in the General Tumor Registry of Calvados and the Cancer Registry of Manche. A Bayesian model was used to map the spatial variation in the incidence of lung cancer in the territory, and an innovative approach was used to evaluate the influence of geographical variability in the socioeconomic environment on the spatial heterogeneity of lung cancer incidence.

Results: The maps of the spatial components showed high contrasts for both genders, and the socioeconomic environment integration in the model made the maps less contrasting. The socioeconomic environment of the population explained one-third of the spatial variation in the incidence of lung cancer in women and one-fifth in men.

Conclusion: The results showed that a non-negligible part of the spatial variation in the incidence of lung cancer could be explained by the geographical distribution of the socioeconomic environment.