4537 Background: Despite guideline-based standard of care recommendations in BC and upper tract urothelial carcinoma (UTUC), treatment remains variable across US. Experts recommend focusing BC care in tertiary centers. We hypothesized that a BCMC model, with expert central pathology and radiology review, may result in changes in corresponding reports, and, thus, treatment recommendations. Methods: Our BCMC clinic format includes simultaneous consultation with Urologic, Medical and Radiation Oncology, with real time expert genitourinary pathology and radiology review. We retrospectively assessed the concordance between outside (pre-BCMC) imaging & pathology review and BCMC review. Differences between pre- and post- BCMC recommendations on management were also assessed; descriptive statistics were used. Results: We identified 233 BC/UTUC patients (pts) referred to BCMC. Complete radiographic and pathologic data were available for 209 pts. Median age at time of evaluation was 68 (27-93) and 85% were PS ECOG 0-1. After BCMC review of outside records, 112 (53.6%) imaging and/or pathology changes were noted, with 57 (27%) pts upstaged. Overall, imaging interpretation was changed in 25% of cases, and 20% of pts were upstaged. BCMC pathology review resulted in changes in 59 (28%) pts. Among those, 42 (71%) had histologic subtype addition or change, 9 (15%) had LVI/CIS status change, and 2 (3.4%) had low to high grade conversion. In terms of pathology staging, 7 (12%) were downstaged, and 5 (8.5%) upstaged. Further diagnostic work-up was recommended in 71/209 (34%) pts, resulting in upstaging in 11/71 (15.5%) of cases. Pre- and post- BCMC-recommended treatment modality differed in 55/209 (26%) pts, while a new treatment modality was added in 28/209 (13%) pts. These recommendations were followed 91.4% of the time (191/209 pts). Conclusions: BCMC initiation at our institution resulted in imaging and/or pathology diagnostic changes in almost half of cases, with approximately a quarter of pts being upstaged. Findings reveal the importance of expert radiology and pathology review in BC. Further study is needed to confirm the proposed benefits and impact of BCMC on treatment response and outcomes.