Analysis of the Methodology of skin cancer incidence registration in German cancer registries

Abstract

Background: Skin cancer is one of the most common cancers in the world and yet non-melanoma skin cancer (NMSC) has been included for the first time in the world cancer Atlas (GLOBOCAN 2018). The reason for this delay is the non-uniform data collection system for skin cancer across the countries. Germany is one of the 10 countries with the highest incidence of skin cancer reported in the world. This rate is estimated based on data collected by the 16 population-based cancer registries in Germany. While Malignant melanoma (MM) is being reported since the 1960s in Germany, NMSC data always faced completion issues because of out-patient based treatment and an extremely large number of cases. The purpose of this study is to analyze the methodology of skin cancer incidence registration followed by the German cancer registries and to assess the quality of data of skin cancer and suggest improvements. Methodology: The information was extracted from annual reports of all the German cancer registries, from the website of Robert Koch Institute, the Manual of cancer registration, through a questionnaire sent via email to all the registries and relevant articles searched on PubMed. Comparison of the methodology with that of Nordic countries was done to suggest improvements. Results: Legislative laws for remuneration to NMSC notifications, changes in ICD coding, and not counting the multiple tumors, all affect the registration process of skin cancer and hence its reported incidence rate. Use of Mortality/ Incidence ratio as an assessment of completeness, implementation of national screening project, and the incomplete TNM staging information, directly or indirectly determine the quality of skin cancer data. This data is more complete for MM as compared to NMSC. All registries replied back to the survey and confirmed these findings. On the other hand, Nordic countries report BCC in a separate file and count multiple skin tumors. Conclusion: There is undoubtedly a huge gap in incidence reporting of skin cancer by the German cancer registries especially for NMSC, and the estimates are not reliable. Looking at the rising incidence of skin cancer and improving survival, more efforts are needed to improve the completion of data like recording the tumor stage and site specifications. Upcoming clinical cancer registries would complement the epidemiological registries and help improve the situation in the future. Influence of screening programs should be included in the incidence reporting and moreover its continuation justified.