Epidemiology of CUP syndrome in Germany

The article presents an overview of the incidence, mortality and survival rates of cancer of unknown primary (CUP) in Germany, based on data from the epidemiological German cancer registries and official cause of death statistics. According to these data approximately 11,000 people per year are diagnosed with CUP, corresponding to 2.3% of all cancers in Germany. For nearly 10,000 people per year the cause of death is given as a malignant neoplasm, without specification of site (ICD-10: C80). Comparisons with recent international data indicate that the incidence of actual CUP in Germany might be overestimated, probably because the differentiation between an actual "unknown" and merely an "unspecified" primary site of the tumor is difficult especially when death certificates are the only source of information. Morphologically, adenocarcinoma is the leading form, while in approximately 30% of cases only unspecific histological results are given. With 5aEuroyear relative survival rates of around 18%, the prognosis of CUP patients is similar to lung cancer, while for younger patients and those with squamous cell carcinoma survival rates are considerably higher.