Acute PresentatiOn of coLorectaL cancer - an internatiOnal snapshot (APOLLO): Protocol for a prospective, multicentre cohort study

Aim: The primary aim of the study is to describe the variation in the operative and nonoperative management of emergency presentations of colon and rectal cancer in an international cohort. Secondary aims will be to develop a risk prediction model for mortality and primary anastomosis and validate risk criteria of large bowel obstruction (LBO) in patients with previously known colorectal cancer undergoing neoadjuvant chemotherapy or awaiting elective surgery. Method: This prospective, multicentre audit will be conducted via the student- and trainee-led EuroSurg Collaborative network internationally over 2023 with 90-day follow-up. Data will be collected on consecutive adult patients presenting to the hospital in an unplanned and urgent manner with colorectal cancer (CRC) due to malignant LBO, perforation, CRC-related haemorrhage, or other related reasons. Primary outcome is 90-day mortality. Secondary outcomes include rates of stomas, primary anastomosis, stenting, preoperative imaging, and complications or readmissions. Conclusion: This protocol describes the methodology for the first international audit on the management of acutely presenting CRC. This study will utilise a large collaborative network with robust data validation and assurance strategies. APOLLO will provide a comprehensive understanding of current practice, develop risk prediction tools in this setting, and validate existing trial results.