Thyroid function tests (TFTs) abnormalities in patients (pts) with metastatic renal cell carcinoma (mRCC) treated with sunitinib

Abstract

4605 Background: Sunitinib is a multi-targeted receptor tyrosine kinase inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptors. It has anti-tumor activity in mRCC pts with toxicity including fatigue. We investigated TFTs abnormalities and related signs and symptoms in pts with mRCC receiving sunitinib. Methods: The medical records of pts with mRCC enrolled in 4 ongoing clinical trials of sunitinib were reviewed. TFTs assessment (TSH, T3 and T4) was undertaken based on the clinical suspicion of treating physicians. Patient demographics, frequency and values of TFTs and any signs and symptoms of thyroid dysfunction were collected. Abnormal TFTs and treatment outcome were correlated. Results: Between 5/2004 and 12/2005, 62 pts (43 males, 19 females) were treated with sunitinib. The median age was 58 years (range, 23–72). Fifty-five pts had TFTs assessed while on treatment and 40 pts (65% of total) had one or more abnormality. Two pts had well-controlled hypothyroidism prior to initiation of sunitinib. TFTs abnormalities were consistent with hypothyroidism in all pts including one who initially developed transient hyperthyroidism. Signs and symptoms possibly related to hypothyroidism were found in 33 pts (53% of total) with abnormal TFTs and were initially attributed to sunitinib. Signs and symptoms included fatigue in 33 pts, anorexia in 20 pts, fluid retention in 17 pts, and skin/hair changes in 13 pts. Thyroid hormone replacement was undertaken in 12 pts and resulted in improvement of symptoms in 6 pts. Among the 40 pts with abnormal TFTs 29 pts had tumor evaluation; 13 had SD, 8 had PR, 2 had CR. There was no correlation between abnormal TFTs and treatment outcome. Conclusions: TFTs abnormalities are common in pts with mRCC treated with sunitinib. Thyroid hormone replacement is indicated in such pts to improve hypothyroidism-related symptoms and possibly to improve treatment tolerance. [Table: see text]