The objective is to show non-inferiority of overall survival between four cycles and six cycles of first-line cisplatin based chemotherapy to determine the optimal duration of chemotherapy in patients with advanced urothelial carcinoma.

Urothelial carcinoma is the fifth most common cancer in men and seventh among women all around the world. Although a complete surgical resection with or without perioperative treatment is the most effective way to offer a potentially curative therapy to patients with these cancers, 25% of the patients initially present with locally or systemically advanced disease. Systemic chemotherapy is the only current modality that provides the potential for a long-term survival in patients with advanced or metastatic urothelial disease.

Cisplatin based combination chemotherapies such as GP, GP-S, MVAC, and dose dense MVAC with G-CSF supports are regarded as a backbone treatment for patients with advanced bladder cancer on the basis of the results from previous studies.

However, there is no consensus on appropriate number of chemotherapy cycles. In phase III trial comparing MVAC with GP, patients were treated with 6 cycles (every 4 weeks) of chemotherapy. In another phase III trial comparing MVAC with HD-MVAC, there is no pre-determined number of cycles, but the median number of cycles were 4 for MVAC and 6 for HD-MVAC.

However, it is hard to complete six or more cycles of cisplatin based chemotherapy due to cumulative toxicities of cisplatin such as neuropathy and development of resistance. The median age of patients with urothelial cancer is 70 years old and significant proportion of the patients already showed impaired performance status (ECOG PS ≥2).

There has already been reported in several trials of NSCLC, which showed that 4 cycles of chemotherapy containing cisplatin has no significant differences in survival or QoL with lower incidences of toxicities compared with 6 cycles of chemotherapy.

The objective of this trial is to assess whether there is any difference in OS between patients who are treated with four cycles of cisplatin based chemotherapy and patients who are treated with 6 cycles of chemotherapy to determine the optimal duration of chemotherapy in patients with advanced urothelial cancer.

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