LAUSR

516 Background: Urachal cancer is a rare form of urothelial cancer representing 0,1-0,2% of bladder cancers. The exact underlying cause of urachal cancer is still widely unknown and there is much speculation on multiple factors such as genetic and environmental ones that may play a role. Moreover, given the lack of treatment consensus, we proposed the first study that assesses the clinical, genetic and molecular features of this disease in Canada. Methods: This ongoing study is recruiting in Canadian centers from the year 2005 onwards. The clinical database is constructed using the hospital electronic medical file. In addition, pathological tissues are centralized for molecular and genetic analysis. Results: To this date, 15 patients were included, 12 males and 3 females. Median age was of 49 years old with a disease distribution of Stage II (4), Stage III (3) and Stage IV (4). 8/15 patients developed metastasis after initial cystectomy in the lungs (n = 7), peritoneum (n = 2), lymph nodes (n = 4), and bone (1). Median survival of all patients was 23 months. Metastatic patients after cystectomy had a shorter overall survival (OS) of 21 months compared to non-metastatic patients (OS – not reached). The majority of metastatic patients (6/8) died of their underlying malignancy. Conclusions: This study is an ongoing country-wide effort to expand knowledge of this poorly studied disease. With ongoing accrual, the clinical features will be better defined and further molecular characterization will be performed to better predict response to therapy.