Background/aims: Middle ligation (ML) of the inferior mesenteric artery (IMA) maintains adequate blood supply to an anastomosis and has no risk of autonomic nerve injury. If apical node dissection of the IMA improves the prognosis, ML and prophylactic dissection of the apical node without division of the IMA above the colic artery may also result in an additional prognostic improvement in patients with sigmoid colon or rectal cancer.
Methodology: Four hundred and one patients with either Dukes' B or Dukes' C colorectal cancer were clinicopathologically examined. In order to evaluate the influence of the prophylactic dissection of the apical node on the prognosis, the two groups of ML with and without apical node dissection were compared.
Results: The 5-year survival rates in the groups of ML and ML with apical node dissection were 90% and 91%, respectively, in 218 Dukes' B patients. The 5-year survival rates in the groups of ML and ML with apical node dissection were 73% and 71%, respectively, in 183 Dukes' C patients. There were no significant differences between the two groups in both Dukes' B and Dukes' C patients.
Conclusions: When ML is adopted for patients with sigmoid colon or rectal cancer, additional dissection of the apical node is not needed.