# Is computed tomography assessment of residual arterial pedicle length following colorectal cancer surgery a useful marker of surgical quality?

## TL;DR

This study examines if measuring residual arterial pedicle length via CT scans is a reliable indicator of surgical quality in colorectal cancer surgery.

## Contribution

The study evaluates the feasibility and reproducibility of RAPL measurement in non-routine CVL surgeries and its association with survival outcomes.

## Key findings

- RAPL measurements showed excellent inter-rater reliability in both anterior resection and right hemicolectomy patients.
- RAPL was not associated with overall or disease-free survival in either surgical group.
- RAPL lacked correlation with nodal harvest in either surgical type, highlighting the need for thorough pathology examination.

## Abstract

In vivo residual arterial pedicle length (RAPL) has been proposed as a quality indicator for central vascular ligation (CVL [i.e., RAPL ≤ 10 mm]) in colorectal cancer (CRC) surgery. However, its survival association in non-routine CVL practice requires clarification. This study aimed to assess the feasibility and reproducibility of measuring RAPL alongside its oncological associations in non-routine CVL surgery.

A prospective cohort study at Concord Hospital was conducted on anterior resection (AR) or right hemicolectomy (RH) patients with stage I to III CRC (1995–2019). Using surveillance computed tomography (CT), RAPL of the inferior mesenteric artery (IMA) or ileo-colic artery (ICA) pedicle was measured independently by two observers. The intra-class correlation coefficient assessed the reproducibility of the measurements. Kaplan-Meier and univariate Cox regression analyses estimated overall survival (OS) and disease-free survival (DFS), while univariate and multivariate linear regression models tested correlations between RAPL and clinicopathological features.

A total of 1425 patients underwent a CRC operation. Post-operative CTs were reviewed in 424 patients, with 422 (mean age 69.0 years [SD 12.3]; 54.0% males) RAPLs measured. The majority studied underwent an AR (59.2%). Excellent inter-rater reliability was noted in AR (ICC = 0.97; P < 0.001) and RH (ICC = 0.89; P < 0.001) patients. No association was observed between RAPL and OS or DFS in either group. Also, RAPL lacked association with nodal harvest in either AR (P = 0.54) or RH (P = 0.16) patients.

The value of RAPL as a quality marker of CRC surgery in non-routine CVL practice has not been confirmed. Furthermore, its lack of association with nodal harvest emphasizes the importance and the need for comprehensive pathology examination of the specimen following resection of CRC.