# Tailored lymph node dissection in right hemicolectomy: a retrospective study focusing on the anterior tissue of the superior mesenteric vein surgical trunk

## TL;DR

This study examines lymph node dissection techniques in colon cancer surgery, finding that extended dissection retrieves more nodes but increases complications.

## Contribution

The study introduces a tailored lymph node dissection strategy based on tumor location and SMV surgical trunk anatomy.

## Key findings

- Dissection extending to the left side of the SMV retrieved significantly more lymph nodes than the right side.
- Extended dissection increased postoperative complications and prolonged bowel recovery time.
- Tumor location above the ileocolic vein root and elevated CA 19-9 levels are risk factors for lymph node metastasis.

## Abstract

The optimal extent of lymph node dissection in right hemicolectomy for colon cancer remains a topic of debate. This study aimed to refine lymph node dissection strategies by investigating the histopathological characteristics of the anterior tissue of the superior mesenteric vein (SMV) surgical trunk.

One hundred sixty-two patients underwent surgery, with their medial resection border determined to be either to the right or left of the SMV. Pathological and perioperative variables were assessed, and the anterior tissue of the SMV was analyzed to quantify lymph nodes and nerve fibers.

Of the patients included, 84 were in the SMV-right group and 78 in the SMV-left group. After propensity score matching (PSM), the SMV-left group with dissection extending to the left side of the SMV and removal of the anterior tissue of SMV surgical trunk, retrieved more lymph nodes (36.9 vs. 26.8, P < 0.001) than the SMV-right group. However, there was no difference in node-positive staging. The SMV-left group also experienced more postoperative complications (16.7% vs. 1.7%, P = 0.011) and prolonged postoperative defecation times (4.2 vs. 3.5, P = 0.035), accompanied by a higher resection of nerve fibers (12.1 ± 4.2/case). Multivariate analysis identified tumor location above the ileocolic vein (ICV) root and elevated preoperative CA 19-9 levels as independent risk factors for metastasis to main lymph nodes.

Right hemicolectomy with extended lymph node dissection improves lymph node retrieval but increases complication risks and prolongs bowel recovery time. For patients with tumors located below the ICV root, a more limited dissection with the right side of the SMV as the medial boundary may be a preferable option, given the low rate of main lymph node metastasis.