Sarcoidosis and cancer revisited: a long-term follow-up study of 555 Danish sarcoidosis patients

For more than 20 yrs it has been debated whether the systemic disease sarcoidosis predisposes to malignant neoplasms. The aim of this study was to examine the occurrence of cancer in Danish sarcoidosis patients observed for 9-30 yrs. The clinical data of 555 consecutive sarcoidosis patients were linked with the nationwide Danish Cancer Registry in a database, comparing the results with the expected incidence in the Danish population, adjusted for sex, age and calendar time. The sarcoidosis patients were diagnosed in two areas during the periods of 1960-1971 and 1970-1981, respectively, and followed until December 31, 1991. No excess of cancer was observed in sarcoidosis patients. A total number of 48 patients were observed with cancer (20 males and 28 females). Cancer occurred 1-29 yrs after sarcoidosis diagnosis (median 14 yrs) The observed versus expected (O/E) ratio was 1.16 (95% confidence interval (CI) 0.75-1.79) in males and 1.28 (95% CI 0.88-1.86) in females. No increased occurrence of lung cancer or malignant lymphoma (O/E ratios 0.23, 95% CI 0.00-1.25 and 1.25, 95% CI 0.02-6.95, respectively) was found. Neither age at diagnosis of sarcoidosis nor clinical sarcoidosis features were indicators of later occurrence of malignancy. The study could not confirm previous reports of an increased occurrence of malignant neoplasms in Danish sarcoidosis patients.