Anastomotic leak after surgery for colon cancer and effect on long-term survival

Aim An anastomotic leak after surgery for colon cancer is a recognized complication but how it may adversely affect long-term survival is less clear because data are scarce. The aim of the study was to investigate the long-term impact of Grade C anastomotic leak in a large, population-based cohort. Method Data on patients undergoing resection for Stage I-III colon cancer between 2008 and 2012 were collected from the Swedish, Norwegian and Danish Colorectal Cancer Registries. Overall relative survival and conditional 5-year relative survival, under the condition of surviving 1 year, were calculated for all patients and stratified by stage of disease. Results A total of 22 985 patients were analysed. Anastomotic leak occurred in 849 patients (3.7%). Five-year relative survival in patients with anastomotic leak was 64.7% compared with 87.0% for patients with no leak (P < 0.001). Five-year relative survival among the patients who survived the first year was 88.6% vs 81.3% (P = 0.003). Stratification by cancer stage showed that anastomotic leak was significantly associated with decreased relative survival in patients with Stage III disease (P = 0.001), but not in patients with Stage I or II (P = 0.950 and 0.247, respectively). Conclusion Anastomotic leak after surgery for Stage III colon cancer was associated with significantly decreased long-term relative survival.