Surgical quality assessment for the prospective study of oncologic outcomes after laparoscopic modified complete mesocolic excision for nonmetastatic right colon cancer (PIONEER study).

BACKGROUND: The modified complete mesocolic excision (mCME) procedure for right-sided colon cancer is a tailored approach based on the original complete mesocolic excision (CME) methodology. Limited studies evaluated the safety and feasibility of laparoscopic mCME using objective surgical quality assessments in patients with right colon cancer. The objectives of the PIONEER study were to evaluate oncologic outcomes after laparoscopic mCME and to identify optimal clinically relevant endpoints and values for standardizing laparoscopic right colon cancer surgery based on short-term outcomes of procedures performed by expert laparoscopic surgeons. MATERIALS AND METHODS: This is an ongoing prospective, multi-institutional, single-arm study conducted at five tertiary colorectal cancer centers in South Korea. Study registrants included 250 patients scheduled for laparoscopic mCME with right-sided colon adenocarcinoma (from the appendix to the proximal half of the transverse colon). The primary endpoint was 3-year disease-free survival. Secondary outcomes included 3-year overall survival, incidence of morbidity in the first 4 weeks postoperatively, completeness of mCME, central radicality, and distribution of metastatic lymph nodes. Survival data will be available after the final follow-up date (June 2024). RESULTS: The postoperative complication rate was 12.9%, with a major complication rate of 2.7%. In 87% of patients, central radicality was achieved with dissection at or beyond the level of complete exposure of the superior mesenteric vein. Mesocolic plane resection with an intact mesocolon was achieved in 75.9% of patients, as assessed through photographs. Metastatic lymph node distribution varied by tumor location and extent. Seven optimal clinically relevant endpoints and values were identified based on the analysis of complications in low-risk patients. CONCLUSIONS: Laparoscopic mCME for right-sided colon cancer produced favorable short-term postoperative outcomes. The identified optimal clinically relevant endpoints and values can serve as a reference for evaluating surgical performance of this procedure.

Technical assessment in minimally invasive complete mesocolic excision: Is the complete mesocolic excision competency assessment tool valid and reliable?

AIM: The complete mesocolic excision competency assessment tool (CMECAT) is a novel tool designed to assess technical skills in minimally invasive complete mesocolic excision (CME) surgery. The aim of this study was to assess construct validity and reliability of CMECAT in a clinical context. METHOD: Colorectal surgeons were asked to submit video recorded laparoscopic CME resections for independent assessment of their technical abilities. The videos were grouped by surgeons' training level, and four established CME experts were recruited as CMECAT assessors. Extended reliability analysis (G-theory) was applied to describe assessor agreement. RESULTS: A total of 19 videos and 72 assessments were included in the analysis. Overall, technical skills assessed by CMECAT improved with increased training level: the experts scored significantly better than the untrained surgeons (3.3 vs. 2.5 points; p < 0.01). On right-sided resections, significantly higher scores were reported with increased training level for all categories and sections, while for left-sided resections, the variance across groups was smaller and significantly higher scores were only reported for oncological safety describing items. Overall, assessor agreement was high (G-coefficient: 0.81). CONCLUSION: This study confirms that CMECAT can be applied to video recorded CME cases for technical skill assessment. Further, it can reliably assess technical performance in right sided CME surgery, where construct validity has now been established. More videos are required to evaluate its validity on left colonic CME. In the future, we hope CMECAT can improve feedback during CME training, serve as a tool in certification processes and contribute to distinguishing CME from conventional surgery in future research.

Validation of the German classification system for quality assessment of right-sided colon cancer specimens.

AIM: The German classification system of the completeness of mesocolic excision aims to assess the quality of right-sided colonic cancer surgery by review of photographs. We aimed to validate the reliability of the classification in a clinical context. METHOD: The study was based on a cohort of patients undergoing resection for right-sided colon cancer in two university hospitals served by the same group of pathologists. Prospectively collected photographs of the specimens were assessed twice by six colorectal surgeons to determine the intra-rater and inter-rater accuracy of the German classification and a modification assessing extended right-sided resections. RESULTS: Specimens from 613 resections for right-sided colon cancer were reviewed. Twenty-one specimens were found to be non-assessable, leaving 436 right hemicolectomies, 139 extended right hemicolectomies and 17 right-sided subtotal colectomies. Intra-rater reliability was 0.57-0.74 and weighted kappa coefficients 0.58-0.74, without differences between subgroups. The percentage of agreement between all six participants was 20.3% for all specimens, 21.1% for right hemicolectomy specimens and 18.1% for extended hemicolectomy and right-sided subtotal colectomy specimens. For the right hemicolectomy specimens, the model-based kappa coefficient for agreement was 0.27 (95% CI 0.24-0.30) and for association 0.45 (95% CI 0.41-0.49). CONCLUSION: The German classification of right hemicolectomy specimens showed low intra-rater reliability and inter-rater agreement and association. The use of this classification for scientific purposes appeared not to be reliable.

Assessment of adjuvant chemotherapy benefits after complete mesocolic excision in patients with colon cancer: Reanalysis of data from the ESCME trial.

AIM: The benefits of adjuvant chemotherapy (AC) in colon cancer after complete mesocolic excision (CME) have not been evaluated sufficiently. We reanalysed the ESCME trial data to investigate the survival benefits and establish AC stratified indications. METHODS: The data of Stage II and III colon cancer patients who received CME in the ESCME trial were reanalysed. Patients were divided into AC and non-AC (NAC) groups. The primary outcomes measured were differences in 5-year cancer-specific survival and disease-free survival (DFS) between the groups. RESULTS: Of the 206 patients enrolled in the study, 125 patients (AC, 49; NAC, 76) had Stage II cancer and 111 (AC, 86; NAC, 25) had Stage III cancer. There were no significant differences in the adjusted 5-year cancer-specific survival and DFS between the AC and NAC groups. Poor differentiation (hazard ratio [HR] 2.947; 95% CI 1.218-7.131) and RAS mutation (HR 3.140; 95% CI 1.363-7.234) affected the 5-year DFS significantly in multivariate Cox regression analysis for Stage II and III cancer, respectively. In subgroup analysis, AC significantly improved 5-year DFS (HR 0.369; 95% CI 0.140-0.978) for Stage III cancer with lymphovascular/perineural invasion compared to NAC. CONCLUSION: The current indication and benefits of AC for colon cancer patients after CME should be re-evaluated. AC is more appropriate for Stage III cancer with lymphovascular/perineural invasion.

[Key vessels assessment and operation highlights in laparoscopic extended right hemicolectomy].

Laparoscopic radical colectomies have been more widely used gradually, among which laparoscopic extended right hemicolectomy is considered as the most difficult procedure. The difficulty of extended right hemicolectomy lies in the need to dissect lymph nodes along the superior mesenteric vein (SMV) and disconnect numerous and possible aberrant vessels. To address this problem, we emphasize two points in key vessel assessment: getting familiar with the anatomy along the medial-to-lateral approach and having a good understanding about the preoperative imaging presentations. An accurately preoperative imaging assessment by abdominal enhanced CT can help the surgeon understand the relative position of the key vessels to be dealt with during operation and the situation of the possible aberrant vessels so as to guide the procedure more effectively and facilitate the prevention and management of the intraoperative complications. During operation, the operator should pay special attention to the management of the vessels in the ileocolic vessel region, Henle's trunk and middle colon vessels. The operation highlights of the key vessels are as follows: (1) The ileocolic vessels: identifying the Toldt's gap correctly and opening the vascular sheath of the SMV securely; making sure that the duodenum is well protected. (2) Henle's trunk: dissecting along the surface of the Henle's trunk; preserving the anterior superior pancreaticoduodenal vein (ASPDV) and main trunk of the Henle's trunk; disconnecting the roots of the right colic vein (RCV) and right gastroepiploic vein (RGEV), and then dissecting lymph nodes along the surface of the pancreas. (3) The middle colon vessels: identifying the root of the middle colon vessel along the lower edge of the pancreas; avoiding entering behind the pancreas; mobilizing the transverse mesocolon sufficiently along the surface of the pancreas. Finally, we discuss and analyze the disputes currently existing in laparoscopic extended right hemicolectomy, including dissection of No.6 lymph nodes, naking the SMA and dissecting lymph nodes around the roots of the branches of SMA. This article shares our experience about laparoscopic extended right hemicolectomy, hoping that it could help beginners master the technique more safely and skillfully.

Simple instruments facilitating achievement of transanal total mesorectal excision in male patients.

AIM: To assess the efficacy of a modified approach with transanal total mesorectal excision (taTME) using simple customized instruments in male patients with low rectal cancer. METHODS: A total of 115 male patients with low rectal cancer from December 2006 to August 2015 were retrospectively studied. All patients had a bulky tumor (tumor diameter ≥ 40 mm). Forty-one patients (group A) underwent a classical approach of transabdominal total mesorectal excision (TME) and transanal intersphincteric resection (ISR), and the other 74 patients (group B) underwent a modified approach with transabdominal TME, transanal ISR, and taTME. Some simple instruments including modified retractors and an anal dilator with a papilionaceous fixture were used to perform taTME. The operative time, quality of mesorectal excision, circumferential resection margin, local recurrence, and postoperative survival were evaluated. RESULTS: All 115 patients had successful sphincter preservation. The operative time in group B (240 min, range: 160-330 min) was significantly shorter than that in group A (280 min, range: 200-360 min; P = 0.000). Compared with group A, more complete distal mesorectum and total mesorectum were achieved in group B (100% vs 75.6%, P = 0.000; 90.5% vs 70.7%, P = 0.008, respectively). After 46.1 ± 25.6 mo follow-up, group B had a lower local recurrence rate and higher disease-free survival rate compared with group A, but these differences were not statistically significant (5.4% vs 14.6%, P = 0.093; 79.5% vs 65.1%, P = 0.130). CONCLUSION: Retrograde taTME with simple customized instruments can achieve high-quality TME, and it might be an effective and economical alternative for male patients with bulky tumors.

Complete mesocolic excision an assessment of feasibility and outcome.

Surgery is the most important factor for radical treatment of colon cancer, and the long-term prognosis can be improved by improving the surgical treatment without increased risk of perioperative mortality. Complete mesocolic excision (CME), in which more extensive lymph node (LN) dissection is performed, has been shown in single-centre studies with historical controls to be associated with better oncological outcome. However, better evidence is needed. The main purpose of this PhD thesis was to investigate whether CME could be implemented in a colorectal surgical department in Denmark, whether more extensive dissection could demonstrate LN metastases outside the mesocolon, and to demonstrate a possible association between CME and improved oncological results without increased risk of perioperative mortality. This thesis includes five articles. Two articles (IV and V) are based on the population of patients undergoing elective resection for colon cancer in the Capital Region from June 2008 to December 2013. Two articles (II and III) are based on data from the local colon database in Hillerød, and the last article (I) is a systematic review concerning the risk of metastases from colon cancer to the central LNs in the mesocolon. Article I found a risk of metastases in central LNs to be reported in 1-22% of the cases of right-sided colon cancers, and in up to 12% of the cases with sigmoid tumours. The populations included and methods used in the studies were very heterogeneous and no definitive conclusions can be drawn. It was shown in article II that the surgical quality, i.e. quality of the specimens assessed by the pathologists, improved with implementation of CME in Hillerød. The vascular tie was higher, and the implementation was not associated with an increased risk of perioperative mortality. Article III demonstrated a risk of LN metastases in the gastrocolic ligament along the stomach for tumours located in the transverse colon, in the ascending or descending colon close to or in the flexures. It occurred in 4% of all patients and 13% of the patients with LN metastases in mesocolon. Resection of these LNs seems advisable for these tumour locations. Article IV showed no association between increased perioperative mortality and CME (n = 529) when compared with non-CME (n = 1,701). The 30-day mortality was 4.2% after CME compared with 3.7% after non-CME (p = 0.605), and the 90-day mortalities were 6.2% and 4.9% (p = 0.219) respectively. Odds ratios for 30-day and 90-day mortalities after CME were respectively 1.07 (95% confidence interval: 0.62-1.80) and 1.25 (0.77-1.94) in the multi-variable logistic regression analyses. Postoperative respiratory failure and need for vasopressors were significantly more frequent in the CME group and, besides CME itself, could be associated with the fewer laparoscopic resections and more severe preoperative comorbidity in the CME Group. Article V demonstrated an association between higher four-year disease-free survival for stage I-III tumours and CME (n = 364) when compared with non-CME (n = 1,031). Most notable was the difference for stage I and II cancers. The four-year disease-free survival for stage I was 100% in the CME group compared with 89.8% (83.1-96.6) in the non-CME group (p = 0.046). For stage II the disease-free survivals were 91.9% (87.2-96.6%) in the CME group and 77.9% (71.6-84.1%) in the non-CME group (p = 0.0033), and for stage III 73.5% (63.6-83.5) and 67.5% (61.8-73.2) (p = 0.13) respectively. In the multivariable Cox regression models, CME was a significant predictive factor for higher dis-ease-free four-year survival for stage I-III patients with hazard ratios (HR) for CME of 0.59 (0.42-0.83, p = 0.0025). For stage II the HR was 0.44 (0.23-0.86, p = 0.018) and for stage III 0.64 (0.42-1.00, p = 0.048).

Combined laparoscopic-assisted nephrectomy and complete mesocolic excision for synchronous renal and colon cancers.

Cancers of the colon and kidney are common malignancies, however, the occurrence of primary synchronous neoplasms of these two organs is uncommon. To the best of our knowledge, this is the first case report of a laparoscopic radical left nephrectomy and extended right complete mesocolic excision (CME) for a patient with synchronous renal and colon cancers. While a radical nephrectomy has long been the standard of care for a renal malignancy, CME has only recently been used. Combined surgeries provide the patient with various benefits such as decreased hospital stay, less postoperative pain and morbidity, early return to work and better cosmoses.