Published online Mar 15, 2019. doi: 10.4251/wjgo.v11.i3.208
Peer-review started: October 2, 2018
First decision: November 15, 2018
Revised: December 6, 2018
Accepted: January 9, 2019
Article in press: January 10, 2019
Published online: March 15, 2019
Surgery has witnessed a paradigm shift in colon cancer management ever since prominent researchers have proposed complete mesocolic excision (CME) as the optimal surgical technique. CME specimens have been demonstrated as superior to standard resections, and patient outcomes have significantly improved. Despite this, adoption among surgeons is still not clear because quality criteria are not well defined. On this basis, researchers have proposed various quality markers - lymph node yield, mesocolon area, distance from central vascular ligation (CVL) to colon margin, etc.
Because quality criteria in colon surgery are not yet defined, CME adoption is still behind total mesorectal excision. A consensus is needed to group already-proven pathological quality markers with newly-advocated radiological markers and to establish standards in colon surgery. The value of measuring arterial stumps on post-operative computed tomography (CT) scans has been previously analysed, but never in a comparative study between CME and standard specimens.
In our advent to better define quality criteria for colon resections, we sought to analyse the value of measuring arterial stumps on post-operative CT scans in a comparative setting between CME and non-CME specimens, for the first time. By testing our hypothesis that arterial stumps are shorter in the CME group and are correlated with prognosis, we aimed to establish arterial stumps as tools to assess CME surgery.
This study was designed as a retrospective analysis and conducted on a prospectively maintained database. Two groups of adult patients were included in consecutive order. All underwent surgery with curative intent for colon cancer (stages I-III UICC 7th edition) and had at least one post-operative good quality contrast-enhanced CT scan that was available for re-evaluation. Group A were operated based on standard CME principles whereas group B underwent conventional colectomy. Measurements of arterial stumps were done by three observers. Shapiro-Wilk test was used to verify normal distribution of data. Kruskal-Wallis test confirmed inter-observer correlation. Stump measurements were analysed comparatively using Student’s t-test. Paired and independent t-test was used to quantify potential for improvement of the ligation height and to compare potentials for improvement between the two groups. Non-normal distribution and non-parametric data was analysed using Kruskal-Wallis test.
From 193 consecutive patients, 58 patients were selected after applying the inclusion and exclusion criteria (29 in CME group, 29 in non-CME group). After comparatively analyzing stump length in both groups, Shorter lengths were obtained in group A, by a mean difference of 35.66 mm (χ2= 27.38, P < 0.001), which was significant for all types of colectomies. Ligations from group A significantly reached their potential height (0.26 ± 12.18 mm from D2PLL; χ2= 0.005, P = 0.944) in comparison with group B were the overwhelming majority failed to reach D2PLL, by a mean difference of 32.14 ± 26.15 mm (χ2 = 21.77, P < 0.001). Moreover, improvement potentials were far shorter in group A than group B (χ2= 22.13, P < 0.001). Significant more variability was found in resections of group B (P = 0.004). No significant difference was found when measurements of three different observers were analysed (P = 0.866). Stump length was statistically correlated with specimen length and lymph node yield (P = 0.018 and P = 0.008 respectively).
Measuring arterial stumps is a simple and standard tool for defining surgical quality of colon resections. It may be, as well, a straightforward prognostic factor given its correlation with lymph node yield.
Our study is a step forward in refining quality criteria for colon surgery. Further research is needed on larger cohorts to compare the value of stump measurement to specimen measurements such as CVL distance or mesocolon surface area. The threshold for CVL should be further analysed, as D3 dissection may not aid in significantly better surgical specimens and outcomes.