The Association Between Sarcoidosis and Malignancy: A Comprehensive Population-Based Cohort Study

Background: Sarcoidosis is a multisystem granulomatous disorder with a variable clinical course and complications. The relationship between sarcoidosis and malignancies remains unclear, including specific malignancy associations with sarcoidosis and whether the association is short-term, long-term, or a result of misdiagnoses or coincidence. This study investigated the association between sarcoidosis and malignancy by analyzing the varying intervals between the diagnoses of these two conditions to clarify their inter-relationship. Methods: This retrospective cohort study included almost 24,000 sarcoidosis patients and matched controls at a 1:5 ratio in patients diagnosed between 2000 and 2015 in Israel. Patients had a median age of 57 years. Malignancy rates were compared across several timeframes: overall, within one year before or after sarcoidosis diagnosis and more than one year. Logistic regression models were employed to estimate odds ratios for the association between sarcoidosis and malignancy, adjusting for sociodemographic and clinical variables. Results: Sarcoidosis patients had a significantly higher prevalence of malignancies (19.5%) compared to controls (13.6%) (p < 0.001). The association remained significant for both hematologic malignancies (OR: 2.94, 95% CI: 2.41-3.57) and solid malignancies (OR: 1.41, 95% CI: 1.27-1.55). The strongest association was observed with lymphoma, particularly within the first year of sarcoidosis diagnosis (OR: 14.88, 95% CI: 8.83-25.1). Elevated odds for malignancies persisted both within one year and beyond, including sarcoma and soft tissue cancers and genitourinary malignancies. Conclusions: Our study confirms a significant association between sarcoidosis and both hematologic and solid malignancies in both the short and long term across various timeframes. These findings emphasize the need for increased clinical vigilance in sarcoidosis patients and highlight the importance of further research into the shared genetic and environmental mechanisms that may underlie this relationship.