Tumor flare of brain metastases upon dose interruption of sunitinib in a patient with metastatic renal cell carcinoma

Abstract Brain metastases from renal cell carcinoma are associated with poor prognosis. Sunitinib is a multi-targeted tyrosine kinase inhibitor used for the treatment of metastatic renal cell carcinoma. It is taken orally on a traditional dosing schedule of 4-week on/2-week off cycles or an alternate dosing schedule of 2-week on/1-week off cycles. Although patients with brain metastases were excluded from the original phase 3 sunitinib registration trial, case reports and an expanded access trial suggest that sunitinib penetrates the blood brain barrier and has central nervous system (CNS) activity. We present a case report which illustrates an unusual presentation of symptomatic brain metastasis progression during the prescribed breaks in treatment during sunitinib monotherapy, and rapid clinical improvement upon resuming sunitinib during the cycle. Patients who develop increased symptoms during the “off treatment” period of sunitinib therapy may have new sites of metastasis. In such patients, appropriate imaging should be obtained to evaluate for disease progression and either a continuous sunitinib dosing schedule or an alternative therapy should be considered.