336 Background: The prognostic impact of prior platinum agent (cisplatin vs. carboplatin) and site of primary (bladder vs. other) in the context of salvage therapy for advanced UC is unknown. Methods: We pooled 10 prospective phase II trials of ≥ second-line therapy for advanced UC with data recorded for prior platinum agent and site of primary in addition to major prognostic factors: TFPC (time from prior chemotherapy), Hb (hemoglobin), PS (performance status), and LM (liver metastasis) status. Cox proportional hazards regression was used to evaluate the association of prior platinum agent and site of primary with overall survival (OS) and progression-free survival (PFS). Trial was included as a stratification factor throughout. Kaplan-Meier method was used to estimate PFS and OS. Results: Of 731 patients overall, 559 had received one prior chemotherapy regimen, 663 were evaluable for prior platinum regimen and 512 for site of primary. The overall median PFS and OS were 2.7 and 6.8 months, respectively. ...