Clinical impact of D3 lymph node dissection preserving left colic artery (LCA) compared to D3 without preserving LCA: Exploratory subgroup analysis of data from randomized controlled trial of laparoscopic versus open surgery for colon cancer from Japan Clinical Oncology Group study JCOG0404.

653 Background: In curative resection of sigmoid colon and rectal cancer, it is unclear whether D3 lymph node dissection preserving left colic artery (LCA) (Group A) is beneficial compared to D3 without preserving LCA (Group B) in terms of clinical outcomes. Preservation of LCA is expected to maintain blood supply which results in preventing anastomotic leakage, intestinal paralysis, and so on. Methods: The data of JCOG0404 (which is a randomized controlled trial comparing open to laparoscopic surgery for stage II/III colon cancer) were used. Eligibility criteria in JCOG0404 included histologically proven colon cancer; T3 or deeper lesion without involvement of other organs; N0-2 and M0. D3 lymph node dissection with or without preserving LCA was identified according to the photographs of the resected field collected for central surgical review in JCOG0404. The short and long-term outcomes were compared between each procedure. Results: Among all randomized 1057 patients in JCOG0404, 631 patients who received assigned sigmoid colectomy and anterior resection were included in the subgroup analysis. The number of patients were 135 in Group A and 496 in Group B. The patient backgrounds did not differ between groups. The median operative time, median blood loss, and the proportion of grade 1 or more anastomotic leakage and intestinal paralysis were not remarkably different (Group A vs. Group B: 185 min vs 186 min, 60 ml vs. 50 ml, 3.0% vs. 5.0%, and 2.2% vs. 3.8%). However, overall postoperative complication occurred more in Group B than in Group A (9.6% and 21.6%, p = 0.022). In terms of efficacy, 5-year relapse-free survival (RFS) and overall survival (OS) tended to be better in Group A than Group B (RFS: 83.7% and 80.5%, HR 1.25 (95% CI 0.79-1.96), OS: 96.3% and 91.1%, HR 2.47 (95% CI 1.13-5.40)). Conclusions: Short and long-term outcomes were better in Group A than Group B. It was considered that D3 lymph node dissection preserving LCA could be alternative treatment for D3 lymph node dissection. Clinical trial information: C000000105.