The Incidence of Cancers in Patients With Nonfunctional Adrenal Tumors: A Swedish Population-Based National Cohort Study

Abstract

Background It is unclear if non-functional adrenal tumors (NFAT) are associated with higher cancer incidence. Objective To analyze the cancer incidence in patients with NFAT. Design Retrospective cohort study. Setting National register-based study. Patients Consecutive patients with NFAT identified in Sweden 2005-2019 and matched controls without adrenal tumors followed up to 15 years. Outcome data were collected from national registers and adjusted for confounders. Both cases and controls were followed until newly diagnosed malignancy, death or until 2019. Measurements Individuals with adrenal hormonal excess or prior malignancy were excluded. Results Among 17,726 cases, 10,777 (60.8%) were women, and the median age was 65 (IQR, 57 to 73) years. Among 124,366 controls, 69,514 (55.9%) were women, and the median age was 66 (IQR, 58 to 73) years. The incidence of any cancer was higher in patients with NFAT compared to controls (hazard ratio (HR) 1.35, 95%CI 1.29-1.40, adjusted HR (aHR) 1.31, 95% CI 1.26-1.37). NFAT was associated with a higher incidence of adrenal, thyroid, lung, stomach and small intestine, kidney, pancreatic, breast and colorectal cancer. Sensitivity analyses did not change the overall results, but associations were not significantly increased after adjustment in patients with NFAT and appendicitis or gallbladder/biliary tract/pancreas disorders. Limitation By adjusting for unclear and benign tumors the cancer incidence may have been underestimated. Conclusion The incidence of cancer was increased in patients with NFAT. Long-term follow-up may be indicated.