Four Cycles Versus Six Cycles of Cisplatin-based Chemotherapy in Metastatic Urothelial Carcinoma

Inclusion criteria: 1. Patients with histologically or cytologically confirmed urothelial cancer 2. Unresectable locally advanced (T3b, N2-3), metastatic (M1), or recurrent disease 3. Age 18 years or older 4. Eastern Cooperative Oncology Group performance status 0-1 5. Not progressed disease status after 2 or 4 cycles of platinum-based chemotherapy 6. Adequate organ and bone marrow function for chemotherapy 7. No history of radiation therapy, or radiation field within 25% of whole marrow would be allowed. If patients underwent radiation therapy in entire pelvis, they are excluded to this study. Patients should discontinue radiation therapy at least 4 weeks before enrollment, and the patients should be recovered from radiation therapy associated adverse events. 8. Women should use contraceptive medication for 6 months after the end of the study or she would be post-menopause status. Men should consent with the contraception for 6 months after the end of the study or he would be infertile. 9. Patients should sign a written informed consent before study entry. Exclusion Criteria: 1. Histologic types other than urothelial cell carcinoma should be excluded. However, urothelial cell types combined with squamous or glandular features are allowed. 2. Patients who showed progressed disease status after 2 or 4 cycles of platinum-based chemotherapy, cannot be treated with additional chemotherapy due to adverse events, or already undertook with reduced dose of more than 50% 3. Presence or history of CNS metastasis 4. Prior systemic chemotherapy (But prior intravesical chemotherapy or immunotherapy was allowed, and recurrent disease after adjuvant or neoadjuvant cisplatin-based systemic chemotherapy is allowed if the last chemotherapy was administered 1 year or more before the patient enrollment) 5. Peripheral sensory neuropathy grade 2 or worse according to NCI CTCAE 6. History of treatment with drugs of another clinical trial within 30 days before enrollment. 7. Concomitant severe medical, surgical, or psychiatric disease or problems which can affect the results of the clinical trial or have possibilities of unexpected medical problems caused be the drug of clinical trial 8. History of another malignancy (but treated malignancy at least two years before enrollment were allowed, and cured non-melanoma skin cancer, any cured in-situ carcinoma, clinically insignificant localized prostate cancer, or papillary thyroid carcinoma are allowed even diagnosed less than 2 years before enrollment). 9. Pregnant or lactating women, women of childbearing potential not employing adequate contraception