Anastomotic leak following low anterior resection in stage IV rectal cancer is associated with poor survival

Background: Anastomotic leak is a serious complication of low anterior resection (LAR). The risk of leak in stage IV rectal cancer patients treated with synchronous or staged resection of the primary tumour and metastatic sites has not been reported. We measured the incidence of anastomotic leak and its association with clinical outcome. Methods: With institutional review board approval, patients undergoing LAR and resection of metastatic disease were analyzed from a prospectively collected colorectal database between 1992 and 2010. Data for use of ileostomy, clinical anastomotic leak, and clinical risk score (for liver metastases, n = 86) were collected. Categorical variables were compared with the χ² test. Estimated overall survival was compared using log-rank method and Cox regression analysis. Results: A total of 184 patients with LAR and stage IV disease were identified. Of those, 123 had curative resection for disease at distant sites. 72 % underwent simultaneous resection, 28 % staged resection. Median follow-up was 2.9 years for survivors. Anastomotic leak occurred in 6.5 %. There was one perioperative death (not attributable to leak). Overall 3-year survival following a leak was significantly worse compared with patients without a leak (35 vs. 73 %, P = 0.01). Clinical leak was associated with worse survival when controlled for use of diverting stoma, operative year, clinical risk score, and timing of resection of metastatic disease. Conclusions: In this series of patients with stage IV rectal cancer, anastomotic leak was uncommon. However, patients who developed a clinical leak following surgery had worse survival. This finding was independent of use of diverting stoma or staged resection.