Incidence of cancer of unknown primary in Sweden: analysis by location of metastasis.
Increasing incidences of cancer of unknown primary (CUP) have been observed in Sweden previously. However, it is not known how the incidence trends for specific locations of metastasis vary. Site-specific data are available on the basis of the ninth international classification of diseases. CUP patients were identified between 1987 and 2008 from the Swedish Family-Cancer Database. Malignant neopla