Hypothyroidism in patients with hepatocellular carcinoma treated by transarterial chemoembolization

Introduction: Transarterial chemoembolization (TACE) is the standard of care for patients with an intermediate or advanced stage of hepatocellular carcinoma (HCC) and compensated liver cirrhosis. The procedure involves the application of approx. 10g of iodide in the form of iodized oil as radiopaque contrast medium, e.g. lipiodol, mixed with a chemotherapeutic agent. While contrast medium induced hyperthyroidism is well known, the development of hypothyroidism is generally not considered in clinical practice. This phenomenon is called Wolff Chaikoff effect and is caused by iodide induced inhibition of thyroid hormone synthesis. It is rarely observed after the administration of water-soluble iodinated radiographic contrast media but should be considered after application of lipid-soluble iodinated contrast media. To date there is very little information regarding the incidence of thyroid dysfunction in patients treated with TACE.

Methods: We, therefore, retrospectively analyzed a cohort of 219 patients with histologically proven HCC who were treated with TACE at our institution between 1997 and 2007. The patients had a mean age of 66 years; 88% were males. The causes of liver disease were chonic hepatitis C in 32%, chronic hepatitis B in 20% and alcohol in 36%; in 12% other or no etiologies could be identified. From 138/219 patients TSH levels before and after TACE were available.

Results: In 23/138 patients (16.7%) TSH suppression was observed after TACE. Among them, 4 patients developed clinical hyperthyroidism requiring medical therapy; 19 patients developed subclinical hyperthyroidism. In 19/138 patients (13.8%) TSH levels increased from a mean before TACE of 3.08µU/ml to a mean of 22.45µU/ml after TACE [range 4.59–76.66µU/ml]. While 6 patients showed a transient hypothyroidism with spontaneous normalization of TSH within 3.2 months, 7 patients were lost to follow-up and 6 patients developed clinical hypothyroidism that required substitution therapy.

Discussion: In conclusion, we found a clinically relevant incidence of thyroid dysfunction after TACE, incl. hypothyroidism. In clinical practice, therefore, patients treated with TACE should be monitored not only for the development of hyperthyroidism but also of hypothyroidism.