Regional variation in incidence for smoking and alcohol related cancers in Belgium.

The prevalence of life habits may vary substantially within a country. Incidence maps of strongly related diseases can illustrate the distribution of these life style habits. In this study we explored the spatial variation in Belgium for different cancers related to alcohol and/or tobacco. From the Belgian Cancer Registry, municipality specific World Standardised incidence rates for the years 2004-2011 are used to create detailed smoothed cancer maps by subsite or histology for cancers of oral cavity, pharynx, larynx, oesophagus, liver and lung. Cancer incidence is compared both visually (from incidence maps) and with Poisson regression analysis using mortality from chronic liver disease and chronic obstructive pulmonary disease as a proxy for alcohol and tobacco prevalence, respectively. The incidence rates for oral cavity, pharyngeal and laryngeal cancer were comparable with the alcohol gradient. However, glottic cancer revealed a pattern that was more comparable with lung cancer. These two tumour types resembled more closely to the smoking pattern. Oesophageal cancer showed two patterns: squamous cell carcinoma was highly comparable with the background alcohol consumption, while adenocarcinoma was unrelated to one of our two proxies. Our approach and results are an encouraging example how data from a young cancer registry can be used in studies describing the regional cancer burden. The results can be useful for primary prevention to increase awareness for the public, authorities and health care professionals in specific subpopulations.