Hematologic toxicity in patients treated with sunitinib for advanced thyroid cancer.

Background: Although thyroid carcinoma is more indolent than other solid tumors, distant metastatic disease due to differentiated thyroid carcinoma (DTC) and medullary thyroid carcinoma (MTC) is often refractory to treatment and thus a challenge for clinicians. New agents such as tyrosine kinases inhibitors have been introduced recently for therapy of metastatic thyroid cancer but they have toxic side effects as well as therapeutic benefits. The objective of this study was to determine the hematologic toxicities of sunitinib, a multiple receptor tyrosine kinases inhibitor, when used to treat progressive, advanced DTC and MTC.