Purpose: To exclude bias of registration evidenced by relevant differences among German cancer registries in the incidence of malignant melanoma (melanocarcinoma).
Methods: Cancer registries in the Federal German states of Hamburg, Schleswig-Holstein, Bremen, Rhineland-Palatinate, Saarland, the Munich District and the County of Münster featured registration data of malignant melanoma diagnosed in 2000 A. D. Figures and incidence rates, distribution of T-stage of the primary tumour were analysed as well as the distribution of sources reporting melanoma to the registries. Details of outpatient treatment of cutaneous melanoma by dermatologists in private practice were investigated.
Results: Data of 2,471 malignant melanoma cases were analysed. The highest age standardised incidence rates were 15.7 per 100,000 women and 19 per 100,000 men while the lowest rates were reported as 7.8 and 6.6 per 100,000, respectively (European standard). The proportion of stage T1 tumours varied between 21.5 and 59.2 %. We observed remarkable variations in the structure of reporting sources among the registries. The proportion of reports from dermatologists in private practice varied between 2.2 and 62 %, with higher proportions associated with more T1-T2 tumours but also lower completeness of stage reports. No clear association was identified between incidence of melanoma and reporting sources.
Conclusion: Malignant melanomas of smaller size (T1-T2) are reported more frequently in an outpatient setting but very often without data. Hospital departments of dermatology contribute high-quality data with better completeness especially for later stage melanomas. Desirable inclusion of notifications from nationwide operating dermatopathology laboratories is complicated by the Federal German structure of cancer registration. Especially in case of malignant melanoma of the skin notification reports from all sectors of the health care system are imperative for valid epidemiological results.