Index of Estimated Benefit from Lateral Lymph Node Dissection for Middle and Lower Rectal Cancer

Aim: To evaluate the clinical benefit from lateral lymph node dissection for middle and lower rectal cancer. Patients and Methods: A total of 229 patients who underwent bilateral lateral lymph node dissection during resection with curative intent for cT3-4 middle or lower rectal cancer from 2002 to 2013 were retrospectively reviewed. The index of estimated benefit from lymph node dissection for all, and each (common iliac, internal iliac and obturator), lateral lymph nodes were compared with the index for mesenteric lymph nodes (perirectal, intermediate and main lymph nodes). Results: The overall incidence of lateral lymph node metastasis was 14.0%. The index for all lateral lymph nodes (10.6) was lower than perirectal lymph nodes (45.3), but higher than intermediate lymph nodes (4.8). Conclusion: Lateral lymph node dissection provides considerable clinical benefit, similar to the benefit provided by intermediate lymph node dissection.