Distant Metastasis in Colorectal Cancer is a Risk Factor for Anastomotic Leakage.

Purpose: The aim of this study was to investigate whether metastatic colorectal cancer (Union for International Cancer Control stage IV disease) represents a risk factor for anastomotic leakage after colorectal surgery without major hepatic resection.
Methods: This retrospective cohort study was based on an existing prospective colorectal database of all consecutive colorectal resections undertaken at the authors' institution from July 2002 to July 2012 (n = 2104). All patients with colorectal resection and primary anastomosis for colorectal cancer were identified (n = 500). A temporary loop ileostomy was constructed in low rectal anastomosis up to 6 cm from the anal verge (n = 128 cases, 26%). A routine contrast enema was undertaken at the occasion of other prospective studies in 254 patients. UICC stage IV disease was present in 94 patients (19%), while 406 patients (81%) had UICC stage I-III disease.
Results: The overall anastomotic leak rate was 2.6% (13/500), 2.2% (11/500) for both clinical and radiological leaks, and 0.8% (2/254) for radiological leaks only. Four were managed conservatively and nine (1.8%) required revision laparotomy. In the case of UICC stage IV disease, the anastomotic leak rate was 6.3% (6/94), while in the case of UICC stage I-III disease the leak rate was 1.7% (7/406). UICC stage IV disease [odds ratio (OR) 4.4, 95% confidence interval (CI) 1.3-14.4; p = 0.015] and diabetes (OR 5.7, 95% CI 1.7-18.7; p = 0.004) were independent risk factors for anastomotic leakage after colorectal surgery.
Conclusions: Patients with stage IV colorectal cancer have an increased anastomotic leak rate after colorectal surgery. Whether this is due to an impaired immune system remains speculative.