Thyrotoxicosis during sunitinib treatment for renal cell carcinoma

Abstract

CONTEXT: Sunitinib malate is an oral tyrosine kinase inhibitor used in the treatment of renal cell carcinoma (RCC) and gastrointestinal stromal tumours. Hypothyroidism has been observed in patients treated with sunitinib, but the mechanism whereby sunitinib induces hypothyroidism is unknown. OBJECTIVE: To describe a series of six patients who developed thyrotoxicosis while on sunitinib for metastatic RCC. SETTING: The study was conducted at Austin Health, a tertiary teaching hospital in Melbourne, Australia. RESULTS: Two patients developed severe thyrotoxicosis within 10 weeks after commencing sunitinib. In contrast, in the four patients who presented with later onset (16-30 weeks) thyrotoxi..