Long-Term Oncological Outcomes After Colorectal Anastomotic Leakage: A Retrospective Dutch Population-based Study.

OBJECTIVE: The aim was to evaluate the impact of anastomotic leak (AL) after colon cancer (CC) and rectal cancer (RC) surgery on 5-year relative survival, disease-free survival (DFS), and disease recurrence. BACKGROUND: AL after CC and RC resection is a severe postoperative complication with conflicting evidence whether it deteriorates long-term outcomes. METHODS: Patients with stage I to IV CC and RC who underwent resection with primary anastomosis were included from the Netherlands Cancer Registry (2008-2018). Relative survival, measured from day of resection, and multivariable relative excess risks (RERs) were analyzed. DFS and recurrence were evaluated in a subset with stage I to III patients operated in 2015. All analyses were performed with patients who survived 90 days postoperatively. RESULTS: A total of 65,299 CC and 22,855 RC patients were included. Five-year relative survival after CC resection with and without AL was 95% versus 100%, 89% versus 94%, 66% versus 76%, and 28% versus 25% for stage I to IV disease. AL was associated with a significantly higher RER for death in stage II and III CC patients. Stage-specific 5-year relative survival in RC patients with and without AL was 97% versus 101%, 90% versus 95%, 74% versus 83%, and 32% versus 41%. AL was associated with a significantly higher RER for death in stage III and IV RC patients. DFS was significantly lower in CC patients with AL, but disease recurrence was not associated with AL after colorectal cancer resection. CONCLUSION: AL has a stage-dependent negative impact on survival in both CC and RC, but no independent association with disease recurrence.