Risk of Cancer of Unknown Primary after Hospitalization for Autoimmune Diseases.
Cancer of unknown primary (CUP) is a heterogeneous syndrome diagnosed at metastatic sites. The etiology is unknown but immune dysfunction may be a contributing factor. Patients with autoimmune diseases were identified from the Swedish Hospital Discharge Register and linked to the Swedish Cancer Registry. Standardized incidence ratios (SIRs) were calculated for subsequent CUP and compared with subj