Regional comparison of cancer incidence, mortality, and survival on the level of federal states in Germany using funnel plots.

Abstract

Population-based cancer registries allow the assessment of regional differences in cancer burden. Comparative cancer statistics are usually reported as ranked bar charts and choropleth maps, which can lead to misinterpretations of the presented figures. The aim of the present study is a regional comparison of cancer statistics in Germany on the level of federal states using funnel plots. Population-based cancer registry data on incidence, mortality, and survival on the level of federal states for the year 2011 were used. All cancer sites combined and the most common cancers were considered for the analysis. Funnel plots were used to compare the regional cancer statistics against the national estimates for Germany by sex, cancer site, and federal state. Cancer incidence and mortality showed large regional variation, which differed by sex and cancer site, whereas for cancer survival, essentially, no excess variation was observed. By taking into account statistical variation, funnel plots proved to be a suitable tool for assessing regional variation in cancer incidence, mortality, and survival and therefore can help improve population-based health management and eliminate cancer health disparities.