Gemcitabine plus cisplatin therapy (GC) is standard therapy for urothelial carcinoma. However, Gemcitabine plus carboplatin therapy (GCb) may be chosen for patients with impaired renal function. In this study, we retrospectively investigated hematotoxicity of GC and GCb. In addition, we experienced split-dose carboplatin regimen in GCb. Therefore, we investigated hematotoxicity of single-dose and split-dose carboplatin in GCb. Grade 4 thrombocytopenia occurred with high frequency in GCb compared with GC. Furthermore, the renal function was maintained by switching from GC to GCb. The respective percentages for grade 4 thrombocytopenia were 62.5％ (single-dose) and 12.5％ (split-dose) in GCb. In addition, relative dose intensity (RDI) of gemcitabine was 67.9％ and 87.5％ and RDI of carboplatin was 94.8％ and 95.8％ respectively. RDI was maintained highly in split-dose compared with single-dose, and split-dose treatment period of up to progressive disease was longer than single-dose treatment. These results suggest that split-dose carboplatin in GCb may become a regimen with tolerability in patients with impaired renal function.
