# Enzymatic Fat Dissolution Improves Detection of Small Lymph Nodes in Colon Cancer Surgery

## TL;DR

A new method using enzymatic fat dissolution helps detect more small lymph nodes during colon cancer surgery, improving staging accuracy.

## Contribution

The study introduces an enzymatic fat dissolution method that outperforms conventional techniques in detecting small lymph nodes.

## Key findings

- The fat dissolution method detected significantly more lymph nodes per patient than the conventional method.
- The method was particularly effective in identifying lymph nodes smaller than 5 mm.
- Lymph node metastasis identification was significantly associated with the fat dissolution method.

## Abstract

Background

Accurate lymph node evaluation is essential for staging colon cancer and guiding postoperative treatment decisions. In this study, we compared the efficacy of a simple enzymatic fat dissolution method with the conventional method for lymph node sampling from specimens after colon cancer surgery.

Methods

We enrolled 58 patients who underwent elective laparoscopic surgery for colon adenocarcinoma between May 2018 and May 2021 at Fukuoka University Hospital in Fukuoka, Japan. The specimens from these patients were treated using fat dissolution and were compared with specimens from 58 patients for which conventional manual palpation was used.

Results

A significantly greater number of lymph nodes were detected by the fat dissolution method compared with the conventional method (average per patient, 27.5 vs. 22.6, P = 0.02). In particular, the between-group difference was significant for lymph nodes measuring <5 mm (average per patient, 26.1 vs. 20.9; P = 0.01). Multivariate analysis showed that, compared with the conventional method, the fat dissolution method was significantly associated with the identification of lymph node metastasis. The positive rate of lymph nodes ≥10 mm in diameter was markedly higher along the inferior mesenteric artery than the ileocolic artery (100% vs. 52.6%).

Conclusions

The use of the fat dissolution method led to an increase in the number of small lymph nodes detected. Rates of metastasis according to lymph node size may depend on the lymph node station.