S. Zaheer1, L. E. Kuo1, J. C. Morrison1, H. Wachtel1, G. C. Karakousis1, D. L. Fraker1, R. R. Kelz1 1University Of Pennsylvania,Department Of Endocrine And Oncologic Surgery,Philadelphia, PA, USA
Introduction:
Hypothyroidism has been estimated to affect 3.7% of the United States population. It has been suggested that hypothyroidism may be a risk factor for thyroid cancer. We sought to examine the association between hypothyroidism and thyroid cancer characteristics.
Methods:
We identified thyroid surgery patients enrolled in our institutional prospective endocrine surgery registry from 2007 to 2013. Patients were included in the study if they were either hypothyroid (Thyroid stimulating hormone (TSH) >4.0 mIU/L) or euthyroid (TSH between 0.4-4.0 mIU/L) at the time of surgical intervention. The primary outcome of interest was thyroid cancer. Tumor characteristics were examined in the subset of patients with thyroid cancer identified on pathologic review. Univariate analyses were performed using the Wilcoxon ranksum test, Fisher’s exact test and Chi square test, as appropriate.
Results:
Of 901 patients included in the study, 537 patients were euthyroid and 364 patients were hypothyroid. There were 634 patients (70%) with a confirmed diagnosis of thyroid cancer. Age, gender and race were evenly distributed in the two groups. Patients with hypothyroidism had an increased incidence of cancer compared with euthyroid patients (88% vs. 58% respectively, p<0.01). Tumor characteristics were more aggressive among hypothyroid patients (see table).
Conclusion:
Amongst a population of thyroid surgery patients, there was a significant association between thyroid cancer and elevated TSH. Moreover, the tumor characteristics associated with hypothyroidism were more aggressive than those seen in the euthyroid state. Clinicians should carefully screen patients with elevated TSH level for nodular disease and, when appropriate, evaluate for thyroid malignancy in a timely fashion.
