A Case of Uterine Leiomyosarcoma with Long-Term Disease Control by Pazopanib.

Uterine leiomyosarcoma (ULMS) is an aggressive tumor associated with high rates of progression, recurrence, and mortality. Pazopanib is the only approved molecular targeted drug for advanced soft tissue sarcoma, and it has been proven to prolong progression-free survival relative to placebo. We herein report a case of ULMS with multiple lung metastases treated with pazopanib, which led to sustained disease control for 44 weeks. A 53-year-old woman was referred to our hospital due to massive uterine bleeding from a uterine corpus tumor mass. Total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed as emergency surgery. The final histopathological diagnosis was uterine leiomyosarcoma, and computed tomography revealed multiple lung metastases. After chemotherapy with 17 cycles of gemcitabine and docetaxel and two cycles of doxorubicin, the lung metastases had increased in size and new lesions had appeared. Pazopanib administration at 800 mg/day was started as third-line therapy. Ten weeks later, the dose of pazopanib was reduced to 600 mg/day because of hepatic impairment and hypertension. However, lung metastases of ULMS were stabilized by pazopanib administration for about 44 weeks without a decline in the patient's quality of life. After 44 weeks of therapy, pazopanib administration was discontinued because of progressive disease and worsening of the patient's respiratory status. Pazopanib is an oral multityrosine kinase inhibitor of vascular endothelial growth factor receptor-1, -2, and -3; platelet-derived growth factor-α and -β; and c-Kit receptor. The role of pazopanib may be clinically significant in the treatment of advanced ULMS.