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Tumor Biology

SAT-302 - The Effects of Preexisting Diabetes on Thyroid Cancer Incidence and Aggressiveness: Results from A Multicenter, International Collaboration.

Saturday, June 13, 2026
9:30 AM - 4:30 PM CT
Location: ENDOExpo; Poster Floor
Disclosure(s):
Rodis D. Paparodis, MD, FNLA: .NovoNordisk: Advisory Board (), Speakers' Bureau (); Ascendis Pharma: Advisory Board (), Grant Recipient (), Honorarium Recipient (); Sanofi: Advisory Board ()
Introduction
Diabetes mellitus (DM) has been linked to increased cancer incidence and severity of in multiple association studies. Nevertheless, data regarding its potential pathophysiological role on the risk for thyroid cancer are conflicting. The aim of this study was to assess the effects of pre-existing DM type 1 (DM1) or type 2 (DM2) on thyroid cancer incidence and aggressiveness.

Methods/Subjects
We performed a retrospective review of data from patients who underwent thyroidectomy in two centers in the US, one in Greece and 11 referral clinics in Greece. We collected data on gender, age at surgery, pre-existing DM (>12 months duration), type of DM, preoperative thyroid treatment, TSH levels and histopathological features. We compared the incidence and aggressiveness of thyroid cancer, according to histopathological report between subjects with DM1, DM2 or non-diabetic (i.e. controls) in a cross-sectional and multivariate analysis.

Results
Out of 9,641 consecutive patients undergoing thyroidectomy, n=3,459 were enrolled in the present study: n=2,479 females (71.7%), mean age 49.1 years, TSH 2.05IU/L; DM1 n=11, DM2 n=361, controls n=3,087, malignant histology n=1,695. On univariate analysis, DM2 was associated with larger tumors, while microscopic extrathyroidal extension, capsular invasion and lymph node involvement was less common in all subjects with diabetes compared to controls. On multivariate analysis using age, gender and preoperative use of thyroid hormone or anti-thyroid medications as covariates, DM2 increased the risk for thyroid cancer by 38%, while DM1 did not produce any statistically significant association. Patients with DM required less treatments with adjuvant I131.

Conclusion
In this large, multicenter, international cohort of patients undergoing thyroidectomy, the presence of DM2 increased the risk for thyroid cancer, but reduced the likelihood of tumor aggressiveness or need for I131 therapy. Further research is needed to clarify this paradox.

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