Background: Anastomotic leak has a negative impact on the prognosis of patients who undergo colorectal cancer resection. However, data on anastomotic leak are limited for stage IV colorectal cancers.
Objective: The purpose of this study was to investigate the impact of anastomotic leak on survival and the decision to administer chemotherapy and/or metastasectomy after elective surgery for stage IV colorectal cancer.
Design: This was a nationwide, retrospective cohort study.
Settings: Data were obtained from the Danish Colorectal Cancer Group, the Danish Pathology Registry, and the National Patient Registry.
Patients: Patients who were diagnosed with stage IV colorectal cancer between 2009 and 2013 and underwent elective resection of their primary tumors were included.
Main outcome measures: The primary outcome was all-cause mortality depending on the occurrence of anastomotic leak. Secondary outcomes were the administration of and time to adjuvant chemotherapy, metastasectomy rate, and risk factors for leak.
Results: Of the 774 patients with stage IV colorectal cancer who were included, 71 (9.2%) developed anastomotic leaks. Anastomotic leak had a significant impact on the long-term survival of patients with colon cancer (p = 0.04) but not on those with rectal cancer (p = 0.91). Anastomotic leak was followed by the decreased administration of adjuvant chemotherapy in patients with colon cancer (p = 0.007) but not in patients with rectal cancer (p = 0.47). Finally, anastomotic leak had a detrimental impact on metastasectomy rates after colon cancer but not on resection rates of rectal cancer.
Limitations: Retrospective data on the selection criteria for primary tumor resection and metastatic tumor load were unavailable.
Conclusions: The impact of anastomotic leak on patients differed between stage IV colon and rectal cancers. Survival and eligibility to receive chemotherapy and metastasectomy differed between patients with colon and rectal cancers. When planning for primary tumor resection, these factors should be considered.