Optimising outcomes in young-onset metastatic colorectal cancer from a multidisciplinary model of care.

56 Background: Australia has the highest incidence of young-onset colorectal cancer (yo-CRC) globally (1). Many young patients present with advanced-stage disease, contributing to poor survival outcomes. Contemporary survival data for young-onset metastatic colorectal cancer (yo-mCRC) is limited; the best estimates are based on a QLD study of patients treated between 2000–2020, reporting a 5-year survival of 19% in yo-CRC versus 10% in older adults (2). Methods: Building on our 2024 data demonstrating 5-year survival rate of 70% in selected yo-mCRC patients (3), we analysed a broader real-world cohort of mCRC patients (n=137) treated within out MDT model. All patients treated since 2016 with a minimum follow up of 3 years were included. The objective was to evaluate survival outcomes and the key enablers of success in radical-intent management. Results: Treatment intent emerged as the strongest predictor of long-term outcomes. Of the 137 patients, 6 were untreatable. Five year survival of all treatable patients was 43% (56/131). Among 131 treatable patients, radical intent - defined as a multimodality strategy aiming for substantial remission or cure - was feasible in 64% of patients aged 55. In this group, 5-year survival was 71.6% for >55 and 86.9% (estimated) for