Thyrotoxicosis during sunitinib treatment for renal cell carcinoma.
BACKGROUND
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.


METHODS
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) thyrotoxicosis, the thyrotoxicosis was relatively mild, self-limiting and rapidly progressed to hypothyroidism. These patients experienced recurrent episodes of thyrotoxicosis in temporal relation to their cyclical sunitinib treatment. One patient had cytological evidence of lymphocytic thyroiditis.


CONCLUSIONS
These findings suggest that sunitinib-induced hypothyroidism may be a consequence of preceding thyroiditis with associated transient thyrotoxicosis. As predictive factors are currently unknown, we suggest regular monitoring of thyroid function in all patients commenced on sunitinib. Clinicians treating patients with sunitinib or other similar kinase inhibitors should to be alerted to thyroid dysfunction as a potential toxicity of these agents.
Grossmann
Mathis
M
Endocrine Unit, Austin Health, Victoria, Australia.
Premaratne
Erosha
E
Desai
Jayesh
J
Davis
Ian D
ID
D000328:Adult; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use; D002292:Carcinoma, Renal Cell / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007211:Indoles / Q000009:adverse effects* / Q000627:therapeutic use*; D007680:Kidney Neoplasms / Q000097:blood / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011758:Pyrroles / Q000009:adverse effects* / Q000627:therapeutic use*; D000077210:Sunitinib; D013971:Thyrotoxicosis / Q000097:blood / Q000139:chemically induced* / Q000175:diagnosis; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D000970:Antineoplastic Agents; D007211:Indoles; D011758:Pyrroles; D013972:Thyrotropin; D013974:Thyroxine; D000077210:Sunitinib