Background: Sarcoidosis patients show dysregulated immune function, which may be related to subsequent cancer. We examined here the overall and specific cancer risks among Swedish subjects who had been hospitalized for sarcoidosis.

Methods: A sarcoidosis research database was created by identifying hospitalized sarcoidosis patients from the Swedish Hospital Discharge Register and by linking them with the Cancer Registry. Standardized incidence ratios (SIRs) were calculated for cancers in sarcoidosis patients compared with subjects without sarcoidosis.

Results: A total of 10 037 patients were hospitalized for sarcoidosis during years 1964–2004. Among them 1045 patients developed subsequent cancer, giving an overall SIR of 1.40 and 1.18 for cancer diagnosed later than 1 year of follow-up. A significant excess was noted for skin (squamous cell), kidney and nonthyroid endocrine tumors and additionally for non-Hodgkin's lymphoma and leukemia. Patients with multiple hospitalizations showed high risks.

Conclusions: A 40% overall excess incidence of cancer was noted among sarcoidosis patients, but the increase was confined mainly to the first year after hospitalization. However, the increased risks of skin cancer and non-Hodgkin's lymphoma and leukemia, especially for those with multiple hospitalizations or hospitalized at old age, call for clinical attention.