Is the ileocolic artery crossing pattern related to oncological outcomes of right-sided colon cancer?

Background: Complete mesocolic excision + D3 lymphadenectomy for right-sided colon cancer is standard procedure in Japan. A postmortem study has shown that in patients with the ileocolic artery (ICA) crossing posterior to the superior mesenteric vein (SMV), D3 lymphadenectomy may be potentially inadequate due to anatomical difficulties in lymphadenectomy of the ventral and lateral areas of the ICA. However, whether the ICA crossing pattern is associated with oncologic outcomes of right-sided colon cancer remains unclear. This study aimed to clarify whether differences in ICA crossing patterns are associated with disease-free survival and overall survival. Methods: In this retrospective study, we searched a prospectively maintained database to identify medical records of patients with right-sided colon cancer who underwent right hemicolectomy and D3 lymphadenectomy. We classified patients into two groups based on the ICA crossing pattern: ICA crossing anterior to the SMV (group A) and ICA crossing posterior to the SMV (group P). We compared oncologic outcomes between the two groups. Results: A total of 336 patients were included in the final analytic cohort: 175 in group A and 161 in group P. There was no significant difference in the number of harvested lymph nodes between the two groups. The two groups did not differ in 5-year overall survival within any disease stage. Similarly, the 5-year disease-free survival rates did not differ significantly between the two groups within any disease stage. We performed univariate and multivariate analyses, which showed the ICA crossing pattern had no clinical relevance. Conclusion: Our study did not show an association between the ICA crossing pattern and oncologic outcomes in patients with right-sided colon cancer who underwent right hemicolectomy with D3 lymphadenectomy.