Successful mammalian target of rapamycin inhibitor maintenance therapy following induction chemotherapy with gemcitabine and doxorubicin for metastatic sarcomatoid renal cell carcinoma.

This study presents a case of metastatic sarcomatoid renal cell carcinoma (RCC) treated with systemic chemotherapy followed by mammalian target of rapamycin inhibitor maintenance therapy. A 63-year-old male presented with lumbago, and lumbar vertebral tumors were detected by magnetic resonance imaging. Subsequent computed tomography (CT) revealed a right renal tumor and CT-guided biopsy of the right renal and left sacroiliac tumors determined pure sarcomatoid carcinoma without a clear cell component. Two cycles of combination chemotherapy comprising of gemcitabine (1,500 mg/m2 on day one) and doxorubicin (50 mg/m2 on day one) resulted in a 20% reduction in the longest diameter of the right renal tumor. However, due to grade 3 neutropenia, the chemotherapy was discontinued and temsirolimus (25 mg once weekly), which binds to the cytoplasmic protein, FKBP-12, and inhibits mTOR, was administered. Stable disease was maintained for 19 months with temsirolimus and no major adverse events, with the exception of grade 2 nausea, were observed. The patient succumbed to their disease at 30 months following the initiation of treatment. These results suggested that systemic chemotherapy followed by temsirolimus maintenance is a feasible treatment option for patients with metastatic sarcomatoid RCC.