Uterine leiomyosarcoma well-controlled with eribulin mesylate

Uterine leiomyosarcoma is a rare type of malignant gynecological tumor and has a poor prognosis; therefore, this tumor is often difficult to treat. Some new drugs have been approved during the past several years in Japan and are expected to be efficacious. Eribulin, one of these drugs, is a natural product of halichondrin B, which is isolated from a marine sponge. A recent clinical trial comparing eribulin with dacarbazine to target liposarcoma and leiomyosarcoma indicated that overall survival (OS) was prolonged by treatment with eribulin. We report a case of uterine progressive leiomyosarcoma that responded to eribulin. A 57-year-old woman was suspected of having leiomyosarcoma based on an endometrial biopsy and imaging examinations. Although the tumor grew toward the uterine artery on the right side of the uterine cervix, we performed a total abdominal hysterectomy and bilateral salpingo-oophorectomy to obtain an outcome of no gross residual disease. However, the margin of the right side of the uterine cervix was histologically positive, so leiomyosarcoma stage IIB (pT2bcN0cM0, FIGO2008) was diagnosed. Gemcitabine and docetaxel therapy was administered postoperatively. However, after three cycles, the residual tumor progressed. Other anticancer drugs were administered but were ineffective. We administered eribulin (1.4 mg/m²) as a fourth-line regimen, and the mass decreased by 32% after four cycles. However, the residual tumor continued to grow after eight cycles. The only adverse event associated with eribulin treatment was mild, grade 2 neutropenia. For our patient, eribulin was effective for her recurrent leiomyosarcoma. In selecting chemotherapy, there are currently no fixed guidelines; we should consider the characteristics and adverse events associated with each drug and patient performance status and comorbidities. In this patient, eribulin was associated with few adverse events, an easy route of administration and a good quality of life. Therefore, eribulin is expected to be efficacious for the treatment of gynecologic sarcoma.