スニチニブ投与に伴う薬剤性血小板減少に対してγグロブリン投与が奏功した進行性腎細胞癌の1例

Abstract

An 81-year-old man was referred to our hospital because of a right renal tumor with vena cava thrombus and multiple lung metastases that were detected by computed tomography (CT) scan during evaluation of respiratory discomfort. We started medical treatment with sunitinib at a dose of 50 mg daily in a 2-weekon, 1-week-off schedule after confirming clear cell renal cell carcinoma by tumor biopsy. After 2-week sunitinib treatment, thrombocytopenia continued and platelet count decreased to 1.8×109/l at day 11 after stopping sunitinib. We needed to administer a total of 60 units platelet transfusion because of persistent thrombocytopenia. Bone marrow aspiration did not reveal myelosuppression or carcinoma invasion to bone marrow. Under the clinical diagnosis of drug-induced thrombocytopenia secondary to sunitinib, we started immunoglobulin therapy at day 23 after stopping sunitinib. Platelet count returned to normal 10 days after starting immunoglobulin. The patient developed exacerbating lung metastasis and carcinomatous lymphangiosis during subsequent course and died of renal cell carcinoma 79 days after starting sunitinib. Thrombocytopenia after sunitinib therapy is often encountered but prolonged thrombocytopenia is rare after stopping sunitinib. This case suggests that immunoglobulin therapy is effective for drug-induced prolonged thrombocytopenia through immunological mechanism.