Endocrine Abstracts

Importance: 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, Settings and Participants: A national retrospective register-based study involving cases with NFAT diagnosed in Sweden 2005-2019 and controls was conducted. Both cases and controls were followed until death or 2020. Individuals with diagnosed adrenal hormonal excess or malignancy were excluded. Follow-up started after 3-months malignancy-free survival following the date of the NFAT diagnosis. Sensitivity analyses were performed in subgroups of individuals in whom we would presume controls would also have had a CT: those with acute appendicitis (in whom we would also assume there was no concern of cancer), and in patients with a combination of gallbladder/biliary tract/pancreas disorders, and 6- and 12-months malignancy-free survival following the date of the NFAT diagnosis.

Setting: A national retrospective register-based study.

Exposures: NFAT diagnosis.

Main outcomes and measures: The primary outcome was all types of cancer, after adjustment for sex, age and comorbidities. Secondary outcomes were specific types of cancer.

Results: Among 17,726 cases, 10,777 (60.8%) were women, and the median (IQR) age was 65 (57;73) years. Among 124,366 controls, 69,514 (55.9%) were women, and the median (IQR) age was 66 (58;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), slightly higher among females than males (HR 1.44, 95% CI 1.36-1.52, aHR 1.34, 95% CI 1.26-1.41 vs. HR 1.28, 95% CI 1.20-1.36, aHR 1.29, 95% CI 1.21-1.37). The incidence of thyroid, lung, stomach and small intestine, kidney, and pancreatic cancer were increased in cases. The thyroid and kidney cancer incidences were particularly high in cases younger than 65 years. Sensitivity analyses did not change the overall results.

Conclusions and Relevance: The incidence of cancer in NFAT was increased. Long-term follow-up is indicated.