Background Previous studies on the association between sarcoidosis and malignancy yielded conflicting results.
Objectives This study was aimed to investigate the risk of malignancy in patients with sarcoidosis in a population-based cohort.
Methods An inception cohort of patients with incident sarcoidosis in 1976–2013 in a geographically well-defined population was identified based on comprehensive individual medical record review. Inclusion required physician diagnosis supported by histopathologic evidence of non-caseating granuloma, radiographic evidence of intrathoracic sarcoidosis, compatible clinical presentation, and exclusion of other granulomatous diseases. For each sarcoidosis subject, two sex and aged-matched comparator subjects without sarcoidosis were randomly selected. Cases and comparators were then cross-indexed with the Cancer Registry of the institution, which collected data on every type of malignancy except for non-melanoma skin cancer, for malignancy ascertainment.
Results 345 incident cases of sarcoidosis and 690 comparators were identified. The median duration of follow-up was 12 years. There was no difference in the prevalence of malignancy at sarcoidosis incidence/index date between the 2 groups (14 cases, 3.8% among cases and 30 cases, 4.3% among comparators, P=0.87) compared to non-sarcoidosis subjects. During follow-up, 37 patients with sarcoidosis and 91 subjects without sarcoidosis developed malignancy with a cumulative incidence at 10 years of 4.1% and 7.1%, respectively. The difference corresponded to a hazard ratio of 0.74 (95% confidence interval (CI), 0.50 -1.09). The cumulative incidences at 10 years for individual types of malignancy were also similar between patients with sarcoidosis and non –sarcoidosis comparators, with non-significant hazard ratios. However, subgroup analysis found that cases with extra-thoracic involvement were at higher risk of incident hematologic malignancy compared with cases without extra-thoracic involvement (HR 1.87; 95% CI 1.09–3.22)
Conclusions Risk of malignancy was similar among patients with sarcoidosis compared to non-sarcoidosis subjects. However, the risk of incident hematologic malignancy was significantly higher among patients with sarcoidosis with extra-thoracic involvement compared to patients without extra-thoracic disease.
Disclosure of Interest None declared