Is radix ligation of the inferior mesenteric artery effective in Japanese-Style D3 radical lymph node dissection for sigmoid colon and rectal cancer surgery?-a single-center retrospective analysis since 2002.

Background: The Japanese treatment guidelines recommend treatment of the root of the inferior mesenteric artery (IMA) (#253) to ensure ligation and dissection of the root of the IMA (#253) in descending colon cancer/sigmoid colon cancer deeper than in T2 [muscularis propria (MP)] cancer. However, #253 complete D3 dissection with IMA root ligation has been reported to increase postoperative complications, such as colonic ischemia, and to have a worse prognosis compared to IMA-preserving D3 system dissection. Therefore, we decided to compare complete IMA dissection with ligation and dissection of the IMA root and preserving the left colonic artery (LCA) preserving group. Methods: A total of 172 patients with stage II/III primary sigmoid colorectal cancer who had undergone radical curative resection were categorized into two groups: the IMA root ligation group (#253 complete D3 dissection group) and the LCA preservation group (94/78 cases), in which the IMA root was preserved and either lymph node sampling dissection or peripheral ligation of the left colorectal artery bifurcation was performed. The 5-year recurrence-free survival (5Y-RFS) and 5-year overall survival (5Y-OS) rates were compared. Results: The overall 5-year follow-up rate was 70.23%. 5Y-RFS and 5Y-OS were tested, and no significant differences were found. Similarly, there were no significant differences in the background factors. In the laparotomy/hand-assisted laparoscopic surgery (HALS)/laparoscopic surgery procedure, complete IMA ligation tended to be more common in the HALS group, whereas LCA preservation tended to be more prevalent in the laparoscopic surgery group. There were no significant differences in the postoperative complications between the groups. Anastomotic failure occurred in 6/3 patients in the IMA complete ligation/LCA preservation groups; bowel obstruction in 5/4; wound infection in 10/5; posterior hemorrhage in 1/4; dysuria in 5/1; and urinary tract infection (including cystitis) in 2/1. Postoperative cerebral infarction, ureteral injury, and thigh paresthesia were each observed in only one case in the complete ligation group. Conclusions: These results showed no significant differences in the 5Y-OS or 5Y-RFS. There was no significant difference in prognosis between patients with and without lymph node dissection at the root of the IMA. Thus, there was no significant difference in prognosis between the complete IMA ligation and LCA preservation groups, with or without IMA dissection. There were no significant differences in complications in the complete ligation group; however, the number of cases seemed large. These results suggest that preservation of the IMA may be safe and effective for stage II/III lymph node dissection in primary sigmoid colorectal cancer.