[Effective treatment of metastatic rhabdomyosarcoma with pazopanib]

Pazopanib, an oral tyrosine kinase inhibitor, is the first molecular-targeted agent approved for the treatment of advanced soft tissue sarcoma(STS). Rhabdomyosarcoma in adults is rare, accounting for less than 3%of all adult STS cases. A 57-year old woman presented with cervical lymphadenopathy. Computed tomography revealed a heterogeneous mass in the retroperitoneum, replacing the entire right kidney. On the basis of the above findings, the patient was diagnosed with alveolar rhabdomyosarcoma. She was first treated with 4 courses of vincristine, actinomycin D, and cyclophosphamide(VAC), which resulted in a partial response. Dose reduction and delay occurred owing to hematological toxicity and febrile neutropenia. As second-line chemotherapy, the patient was administered a single daily dose of 800 mg of pazopanib. Because of an episode of hand-foot syndrome and hepatic impairment, the 800-mg daily dose of pazopanib was reduced to a daily dose of 600 mg, which had to be further reduced to a daily dose of 400 mg owing to fatigue and anorexia. The patient maintained a partial response for a total of 4.3 months when treated with pazopanib. Therefore, this drug may be a new treatment option for patients showing metastatic STS after previous chemotherapy.