Post-operative computed tomography scan – reliable tool for quality assessment of complete mesocolic excision

Abstract

BACKGROUNDQuality control in colon cancer surgery is an ongoing debate ever since standardization proved to be highly efficient in improving survival in rectal cancer. Complete mesocolic excision (CME) is widely acclaimed as the new gold-standard in colon cancer resections, thus it is imperative to establish quality criteria of CME in order to make it easily understood and verified by surgeons worldwide. One simple and reproducible tool could be the measurement of arterial stumps postoperatively and a straightforward way to test its reliability is to test it in a comparative study between CME and non-CME surgery.AIMTo validate arterial stump measurement as a surgical quality tool by comparing CME with conventional radical colectomies.METHODSThis was a retrospective study, carried out on a prospective database. We collected data from two groups of patients, divided according to standard CME with D2 central vascular ligation (group A) and non-standardized surgery (group B). The two groups were compared with regard to the arterial stump length after right- and left-sided colectomies for colon cancer. The actual stump lengths of the ileocolic artery (ICA) and inferior mesenteric artery (IMA) were compared with their theoretical best D2 position of predicted ligation levels (D2PLLs) for calculating the potential for improvement. Measurements on follow-up computed tomography scans were carried out by three observers. Pathological data were recorded (specimen length, lymph node yield) and correlated with stump length.RESULTSWe analysed 58 colectomies. The stump lengths (mean ± SD) in group A were 16.97 ± 4.77 mm for ICA and 31.70 ± 15.71 mm for IMA, whereas group B had 49.93 ± 20.29 mm for ICA and 67.24 ± 28.71 mm for IMA. 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. Except for a 5.85 ± 4.71 mm difference for right colectomies, all the ligations from group A significantly reached their potential height (0.26 ± 12.18 mm from D2PLL; χ2 = 0.005, P = 0.944). Apart from three left colectomies, group B failed to reach D2PLL, by a mean difference of 32.14 ± 26.15 mm (χ2 = 21.77, P < 0.001). The calculated improvement potentials were significantly shorter in group A than in group B, by a mean of 31.88 mm (χ2 = 22.13, P < 0.001). The large spread of results in group B showed that there is significant variability (P = 0.004) when compared to standard surgery. Significant correlations were found between stump length, specimen length and number of lymph nodes (P = 0.018 and P = 0.008 respectively). No statistical difference was found between observers’ measurements (P = 0.866).CONCLUSIONArterial stump monitoring is a significant step in defining surgical quality, as longer stumps contain residual mesocolic tissue and correlate with major prognostic factors.

Postoperative Quality Assessment Score Can Select Patients with High Risk for Locoregional Recurrence in Colon Cancer

“…All 3600 unique entries were individually analyzed for inclusion and exclusion criteria. Of these, 502 passed all the eligibility criteria (Figure 1) and were recorded with the following information to input in the analysis score: age at surgery, surgical department, colectomy date and type, eligible post-operative CT scan, time interval from surgery to post-operative CT, arterial stump angiometry parameters consistent with previous work published from our workgroup (actual stump length; theoretical best D2 position of predicted ligation level (D2PLL); theoretical best D3 position of predicted ligation level (D3PLL); D2 improvement potential (D2IP); D3 improvement potential (D3IP)) [9], pathological specimen parameters, established as independent prognostic factors for LRR [24,40,41] (pTNM stage, histological type of cancer; degree of differentiation; number of LNs, lymph-node index (LNI), expressed as the ratio between positive and total LNs; perineural [42], lymphatic and vascular invasion; tumor deposits (pN1c)), total follow-up interval, presence and type of LRR, and LRR-free survival (LRFS). The primary long-term oncological outcome was the LRFS.…”

“…The technical aspects of the imaging protocol for the patients scanned at the IRO were consistent with previous work published from our workgroup [9]. The radiology department examined 400 patients included in our study on a BrightSpeed 16SL CT scanner with 16 detectors (GE Healthcare, Waukesha, WI, United States).…”

“…Some professional and national societies such as the American Japanese, Norwegian and French colon cancer societies recommend CME but with variations regarding the lymphadenectomy level [3][4][5][6][7][8]. The concept of CME with central vascular ligation (CVL) provides an elegant anatomical standardization, but it is still not used universally, with only tertiary centers and colorectal cancer specialists performing CME with consistent precision [2,[9][10][11]. Moreover, surgical centers and countries with an interest in adopting CME with standardized systematic D2 or D3 lymphadenectomy have shown the benefits of a good surgical quality care program in reducing locoregional recurrence (LRR) [12][13][14][15].…”

“…A predictable instrument of quality control was presented in our previous studies—the arterial stump length (ASL), which correlates with the number of harvested LNs. We believe that the actual quantitative length of the arterial stump, rather than the unspecific qualitative description of vascular ligation (D 2 /high/central/D 3 ), could be a better quality marker and may be included in a score of LRR prediction, alongside the established risk factors [ 9 , 28 ].…”

Predictive value of computed tomography with coronal reconstruction in right hemicolectomy with complete mesocolic excision for right colon cancers: a retrospective study

“…Portal phase MSCT data were used for coronal reconstruction because these data can simultaneously show the central veins and arteries for right hemicolectomy, including the ICV, ICA, GTH, SMV and SMA. Preoperative visualisation of these vessels can be used to determine the extent of the CVL region during right hemicolectomy, whilst postoperative visualisation of these vessels can be used to assess the quality of CME [ 27 ].…”