Complete mesocolic excision (CME) impacts survival only for Stage III right-sided colon cancer: a systematic review and meta-analysis.

INTRODUCTION: Complete mesocolic excision (CME) is widely adopted for its assumed superior oncological outcome. However, it's unclear if all right-sided colon cancer patients benefit from CME. The aim of this systematic review is to investigate whether CME contributes to postoperative outcomes and to determine the surgical indications for CME. MATERIAL AND METHODS: We searched eligible articles about CME versus non-CME procedures for right-sided colon cancer in the OVID Medline, Embase, and Cochrane CENTRAL databases, and a meta-analysis was conducted. RESULTS: Twenty-two articles and seven abstracts involving 8088 patients were included in this study. Among them, 3803 underwent CME and 4285 non-CME procedures. The analysis showed that CME was favoured for three-year disease-free survival (DFS) and overall survival (OS), for local, systemic, and total recurrence, and for hospital stay durations. However, increased vascular injury and longer surgery time were observed in CME. Regarding the three-year OS, the superiority of CME was observed only in Stage III. Additionally, no significant differences were observed between CME and non-CME groups regarding overall complications, 30-day readmission rates, reoperation, or postoperative mortality rates. CONCLUSIONS: CME for right-sided colon cancer should be considered, particularly in Stage III patients, to contribute to improved oncological outcomes. However, careful attention must be paid to the increased risk of vascular injury.

Clinical validation of 3D virtual modelling for laparoscopic complete mesocolic excision with central vascular ligation for proximal colon cancer.

INTRODUCTION: Laparoscopic Complete Mesocolic Excision (CME) with Central Vascular Ligation (CVL) in colon cancer surgery has not been broadly adopted in part because of safety concerns. Pre-operative 3-D virtual modelling (3DVM) may help but needs validation. METHODS: 3DVM were routinely constructed from CT mesenteric angiograms (CTMA) using a commercial service (Visible Patient, Strasbourg, France) for consecutive patients during our CMECVL learning curve over three years. 3DVMs were independently checked versus CTMA and operative findings. CMECVL outcomes were compared versus other patients undergoing standard mesocolic excision (SME) surgery laparoscopically in the same hospital as control. Stakeholders were studied regarding 3DVM use and usefulness (including detail retention) versus CTMA and a physical 3D-printed model. RESULTS: 26 patients underwent 3DVM with intraoperative display during laparoscopic CMECVL within existing workflows. 3DVM accuracy was 96 % re arteriovenous variations at patient level versus CTMA/intraoperative findings including accessory middle colic artery identification in three patients. Twenty-two laparoscopic CMECVL with 3DVM cases were compared with 49 SME controls (age 69 ± 10 vs 70.9 ± 11 years, 55 % vs 53 % males). There were no intraoperative complications with CMECVL and similar 30-day postoperative morbidity (30 % vs 29 %), hospital stay (9 ± 3 vs 12 ± 13 days), 30-day readmission (6 % vs 4 %) and reoperation (0 % vs 4 %) rates. Intraoperative times were longer (215.7 ± 43.9 vs 156.9 ± 52.9 min, p=<0.01) but decreased significantly over time. 3DVM surveys (n = 98, 20 surgeons, 48 medical students, 30 patients/patient relatives) and comparative study revealed majority endorsement (90 %) and favour (87 %). CONCLUSION: 3DVM use was positively validated for laparoscopic CMECVL and valued by clinicians, students, and patients alike.

Comparison between laparoscopic complete mesocolic excision and D2 radical operation in colon carcinoma resection: A propensity score matching analysis.

BACKGROUND: Surgery remains the most effective treatment for colon cancer. However, there are still controversies regarding the tumor treatment effect, prognosis, and perioperative impact of complete mesocolic excision (CME) surgery in colon carcinoma resection. OBJECTIVE: This study aims to compare laparoscopic complete mesocolic excision (LCME) and traditional open D2 radical surgery in colon carcinoma resection through a retrospective analysis using 1:1 propensity score matching (PSM). METHODS: 98 cases undergoing LCME or open D2 colon carcinoma resection at our hospital from January 2014 to November 2021 were retrospectively collected. After excluding cases and 1:1 matching using PSM based on baseline clinical data, 86 patients were assigned in research queue. 43 patients were in each group. Two groups were compared for general clinical baseline indicators. Surgical results and postoperative adverse events of patients were also compared. Disease-free survival (DFS) rate and overall survival (OS) rate was analyzed. RESULTS: After 1:1 PSM matching, there was no statistically significant differences in baseline data between the LCME group and D2 group (P> 0.05). LCME was characterized by longer total duration of surgery (P< 0.001), less intraoperative bleeding volume (P< 0.001), more postoperative drainage fluid volume (P< 0.001), greater number of lymph nodes retrieved (P= 0.014). No statistically differences was observed regarding intraoperative blood transfusion, hospital stay, Clavien-Dindo complicating disease classification (all P> 0.05), 1 and 3-year DFS rate (P= 0.84) and OS rate (P⩾ 0.1). CONCLUSION: LCME had a longer duration of surgery but less intraoperative bleeding volume and more postoperative drainage fluid volume and retrieved lymph nodes compared to D2 radical surgery. LCME surgery is comparable to D2 surgery in terms of postoperative prognosis, but LCME surgery shows a positive trend in the overall survival curve.

Learning curve and safety of the implementation of laparoscopic complete mesocolic excision with intracorporeal anastomosis for right-sided colon cancer: results from a propensity score-matched study.

BACKGROUND: Retrospective studies and randomized controlled trials support the safety of laparoscopic complete mesocolic excision (CME) for the treatment of right-sided colon cancer (RSCC). Few studies, however, examine the learning curve of this operation and its impact on safety during an implementation period. We aim to evaluate the learning curve and safety of the implementation of laparoscopic CME with intracorporeal anastomosis for RSCC. METHODS: Consecutive patients undergoing a laparoscopic right colectomy with intracorporeal anastomosis for RSCC between January 2016 and June 2023 were included. Clinical, perioperative, and histopathological variables were collected. Correlation and cumulative sum (CUSUM) analyses between the operating time and case number were performed. Breakpoints of the learning curve were estimated using the broken-line model. CME and conventional laparoscopic right colectomy outcomes were compared after propensity score matching (PSM). RESULTS: Two hundred and ninety patients underwent laparoscopic right colectomy during study period. One hundred and eight met inclusion criteria. After PSM, 56 non-CME and 28 CME patients were compared. CME group had a non-statistically significant tendency to a longer operating time (201 versus 195 min; p = 0.657) and a shorter hospital stay (3 versus 4 days; p = 0.279). No significant differences were found in total complication rates or their profile. Correlation analysis identified a significant trend toward operating time reduction with increasing case numbers (Pearson correlation coefficient = - 0.624; p = 0.001). According to the CUSUM analysis, an institutional learning curve was deemed completed after 13 cases and the broken-line model identified three phases: learning (1-6 cases), consolidation (7-13 cases), and mastery (after 13 cases). CONCLUSION: The learning curve of laparoscopic CME for RSCC can be achieved after 13 cases in centers with experience in advanced laparoscopic surgery and surgeons with familiarity with this technique. Its implementation within this setting seems to be as safe as performing a conventional right colectomy.

Comparing cranial-caudal-medial and medial-lateral approaches for laparoscopic right hemicolectomy: a propensity score-matched analysis.

BACKGROUND: The cranial-caudal-medial approach (CCMA) has been proposed for laparoscopic right hemicolectomy nowadays. This study aimed to investigate the safety and oncological efficacy of CCMA in the treatment of right-sided colon cancer compared to the medial-lateral approach (MLA). METHODS: Patients diagnosed with right-sided colon cancer were included from February 2015 to June 2018, retrospectively, dividing into the CCMA group and the MLA group. We compared the basic characteristics and the short-term and long-term outcomes in two groups. RESULTS: Two hundred and ninety-six patients were included in this study. The baseline characteristics were similar in two groups. Compared with MLA group, CCMA group exhibited shorter operation time (136.3 ± 25.3 min vs. 151.6 ± 21.5 min, P < 0.001), lower estimated blood loss (44.1 ± 15.2 ml vs. 51.4 ± 26.9 min, P = 0.010), and more harvested lymph nodes (18.5 ± 7.1 vs. 16.5 ± 5.7, P = 0.021). The 5-year overall survival (OS) rate for the CCMA group was 76.5%, and the 5-year disease-free survival (DFS) rate was 72.3%, both of which were not inferior to the MLA group. No significant difference was found between two groups in terms of other clinical parameters. CONCLUSION: The CCMA in laparoscopic right hemicolectomy is safe and feasible, making the anatomical plane clearer. This approach can shorten the operation time, reduce intraoperative blood loss, harvest more lymph nodes, and yield satisfactory oncological outcomes.

Comparison of Postoperative Outcomes and Long-Term Survival Rates between Patients Who Underwent Robotic and Laparoscopic Complete Mesocolic Excision for Right-Sided Colon Cancer.

Introduction: Right colon cancer often requires surgical intervention, and complete mesocolic excision (CME) has emerged as a standard procedure. The study aims to evaluate and compare the safety and efficacy of robotic and laparoscopic CME for patients with right colon cancer and 5-year survival rates examined to determine the outcomes. Materials and Methods: Patients who underwent CME for right-sided colon cancer between 2014 and 2021 were included in this study. Group differences of age, body mass index, operation time, bleeding amount, total harvested lymph nodes, and postoperative stay were analyzed by the Mann-Whitney U test. Group differences of sex, American Society of Anesthesiology, and tumor, node, and metastasis stage were analyzed by the Chi-squared test. Disease-free and overall survival were assessed using Kaplan-Meier curves with the log-rank Mantel-Cox test. Results: From 109 patients, 74 of them were 1:1 propensity score matched and used for analysis. Total harvested lymph node (P ≤ .001) and estimated blood loss (P = .031) were found to be statistically significant between the groups. We found no statistically significant difference between the groups in terms of disease-free and overall survival (P = .27, .86, respectively), and the mortality rate was 9.17%, with no deaths directly attributed to the surgery. Conclusions: Study shows that minimally invasive surgery is a feasible option for CME in right colon cancers, with acceptable overall survival rates. Although the robotic approach has a higher lymph node yield, there was no significant difference in survival rates. Further randomized trials are needed to determine the clinical significance of both approaches.

Quality assessment of surgery for colorectal cancer: Where do we stand?

Quality assurance in surgery has been one of the most important topics of debate among colorectal surgeons in the past decade. It has produced new surgical standards that led in part to the impressive oncological outcomes we see in many units today. Total mesorectal excision, complete mesocolic excision (CME), and the Japanese D3 lymphadenectomy are now benchmark techniques embraced by many surgeons and widely recommended by surgical societies. However, there are still ongoing discrepancies in outcomes largely based on surgeon performance. This is one of the main reasons why many countries have shifted colorectal cancer surgery only to high volume centers. Defining markers of surgical quality is thus a perquisite to ensure that standards and oncological outcomes are met at an institutional level. With the evolution of CME surgery, various quality markers have been described, mostly based on measurements on the surgical specimen and lymph node yield, while others have proposed radiological markers (i.e. arterial stumps) measured on postoperative scans as part of the routine cancer follow-up. There is no ideal marker; however, taken together and assembled into a new score or set of criteria may become a future point of reference for reporting outcomes of colorectal cancer surgery in research studies and defining subspecialization requirements both at an individual and hospital level.

Robotic approach to colonic resection: For some or for all patients?

The robotic approach is rapidly gaining momentum in colorectal surgery. Its benefits in pelvic surgery have been extensively discussed and are well established amongst those who perform minimally invasive surgery. However, the same cannot be said for the robotic approach for colonic resection, where its role is still debated. Here we aim to provide an extensive debate between selective and absolute use of the robotic approach for colonic resection by combining the thoughts of experts in the field of robotic and minimally invasive colorectal surgery, dissecting all key aspects for a critical view on this exciting new paradigm in colorectal surgery.

Laparoscopic right colectomy: correct technique based on key anatomical principles.

Since the early1990s, laparoscopic right colon resections have been the most performed advanced laparoscopic procedures just after laparoscopic left colectomies and sigmoid resections. Indications for laparoscopic right colectomies are either benign or malignant diseases. Despite its many indications, a laparoscopic right or extended right colectomy is mostly performed for cancer of the caecum, the ascending colon, the hepatic flexure or the proximal transverse colon. Worldwide, colorectal cancer is the third most diagnosed cancer: an estimated 1,880,725 people were diagnosed with colorectal cancer in 2020, out of which 1,148,515 were colon cancer cases and 40% were located in the right colon. These figures make an oncologic sound surgery for right colon cancer of the utmost relevance. More recently, complete mesocolic excision has been advocated as the optimal choice in term of radicality, especially in node-positive patients with right colon cancer. Laparoscopic standard right colectomy and extended right colectomy with or without CME should be performed according to defined principles based on a close knowledge of key anatomical landmarks. This knowledge will allow to trace anatomical structures and drive instruments along the correct surgical planes and has its foundations in teachings from surgeons and scientists of past and present time.

Resultados perioperatorios de la implementación de la resección completa del mesocolon por vía laparoscópica en cáncer de colon derecho y transverso

Introducción: La técnica de resección completa del mesocolon (RCM) en la hemicolectomía derecha consiste en la disección por planos embriológicos para lograr la resección completa del envoltorio mesocolónico, además de una ligadura vascular central (LVC) con linfadenectomía D3, que no se realiza normalmente con la técnica estándar. Esta técnica se asocia a mejores resultados de sobrevida global y libre de enfermedad que la cirugía convencional en trabajos retrospectivos. Sin embargo, no existen datos de su implementación a nivel nacional. El objetivo de este estudio es evaluar los resultados perioperatorios de la implementación del RCM en un centro universitario en nuestro medio. Materiales y Método: Estudio retrospectivo de cohorte de pacientes consecutivos sometidos a hemicolectomía derecha laparoscópica con técnica de RCM-LVC entre Enero 2022 y Junio 2023. Se recopilaron variables demográficas, perioperatorias, postoperatorias e histopatológicas. Los resultados se analizaron utilizando estadística descriptiva. Resultados: En el periodo, 29 pacientes se sometieron a RCM laparoscópica (mediana de edad 66(57-76) y 15(52%) sexo femenino). La mediana del tiempo quirúrgico fue 202,9 minutos. No hubo casos de conversión, filtración anastomótica, ni mortalidad. Hubo morbilidad en 9 casos (31%) y de estos solo 1(3,4%) fue Clavien-Dindo III (hematoma Pfannenstiel reintervenido). No hubo lesiones vasculares intraoperatorias. Mediana de hospitalización de 3 días. Doce casos (41%) eran etapa II y 8(28%) etapa III. La mediana de linfonodos resecados fue 23(18-28). Conclusión: Esta serie demuestra que la implementación de la RCM-LVC por vía laparoscópica para el tratamiento del cáncer de colon derecho y transverso es factible en centros con experiencia en cirugía colorrectal laparoscópica avanzada.

Introduction: Complete mesocolic excision (CME) consists in the dissection on embryologic planes in order to achieve a complete resection of the mesocolic envelope and performing a central vascular ligation (CVL) with a D3 lymphadenectomy which is not routinely done for standard right colectomies. CME has been associated with better overall survival and disease-free survival in comparison with conventional surgery in retrospective studies. However, there is no data on its implementation in Chile. The aim of this study is to assess the perioperative results of the implementation of CME in our center. Methods: A retrospective cohort study was conducted. Consecutive patients undergoing a laparoscopic right hemicolectomy with CME-CVL between January 2022 and June 2023 were included. Demographic, perioperative, postoperative and histopathological data were collected. Results were analyzed using descriptive statistics. Results: During the study period, 34 patients underwent CME; 29 of them underwent laparoscopic CMECVL (median age 66 (57-76) and 15 (52%) female). The median operating time was 202,9 minutes. There were no cases of conversion, anastomotic leakage or mortality. There was morbidity in 9 cases (31%) and one of these (3,4%) was a Clavien-Dindo III morbidity (reoperation due to a Pfannenstiel haematoma). There were no intraoperative vascular injuries. The median length of stay was 3 days. Twelve cases (41%) were stage II and 8(28%) stage III. The median number of lymph nodes harvested was 23(18-28). Conclusion: This series demonstrate that the implementation of laparoscopic CME-CVL for right and transverse colon cancer is feasible in centers with experience in advanced laparoscopic colorectal cancer.

Effect of complete mesocolic excision (cme) on long-term survival after right colectomy for cancer: multivariate meta-analysis and restricted mean survival time estimation.

INTRODUCTION: Debate exists concerning the impact of complete mesocolic excision (CME) on long-term oncological outcomes. The aim of this review was to condense the updated literature and assess the effect of CME on long-term survival after right colectomy for cancer. METHODS: PubMed, MEDLINE, Scopus, and Web of Science were searched through July 2023. The included studies evaluated the effect of CME on survival. The primary outcome was long-term overall survival. Restricted mean survival time difference (RMSTD), hazard ratio (HR), and 95% confidence intervals (CI) were used as pooled effect size measures. GRADE methodology was used to summarize the certainty of evidence. RESULTS: Ten studies (3665 patients) were included. Overall, 1443 (39.4%) underwent CME. The RMSTD analysis shows that at 60-month follow-up, stage I-III CME patients lived 2.5 months (95% CI 1.1-4.1) more on average compared with noCME patients. Similarly, stage III patients that underwent CME lived longer compared to noCME patients at 55-month follow-up (6.1 months; 95% CI 3.4-8.5). The time-dependent HRs analysis for CME vs. noCME (stage I-III disease) shows a higher mortality hazard in patients with noCME at 6 months (HR 0.46, 95% CI 0.29-0.71), 12 months (HR 0.57, 95% CI 0.43-0.73), and 24 months (HR 0.73, 95% CI 0.57-0.92) up to 27 months. CONCLUSIONS: This study suggests that CME is associated with unclear OS benefit in stage I-III disease. Caution is recommended to avoid overestimation of the effect of CME in stage III disease since the marginal benefit of a more extended resection may have been influenced by tumor biology/molecular profile and multimodal adjuvant treatments.

Developing a phantom for simulating robotic-assisted complete mesocolic excision using 3D printing and medical imaging.

BACKGROUND: Robotic-assisted complete mesocolic excision is an advanced procedure mainly because of the great variability in anatomy. Phantoms can be used for simulation-based training and assessment of competency when learning new surgical procedures. However, no phantoms for robotic complete mesocolic excision have previously been described. This study aimed to develop an anatomically true-to-life phantom, which can be used for training with a robotic system situated in the clinical setting and can be used for the assessment of surgical competency. METHODS: Established pathology and surgical assessment tools for complete mesocolic excision and specimens were used for the phantom development. Each assessment item was translated into an engineering development task and evaluated for relevance. Anatomical realism was obtained by extracting relevant organs from preoperative patient scans and 3D printing casting moulds for each organ. Each element of the phantom was evaluated by two experienced complete mesocolic excision surgeons without influencing each other's answers and their feedback was used in an iterative process of prototype development and testing. RESULTS: It was possible to integrate 35 out of 48 procedure-specific items from the surgical assessment tool and all elements from the pathological evaluation tool. By adding fluorophores to the mesocolic tissue, we developed an easy way to assess the integrity of the mesocolon using ultraviolet light. The phantom was built using silicone, is easy to store, and can be used in robotic systems designated for patient procedures as it does not contain animal-derived parts. CONCLUSIONS: The newly developed phantom could be used for training and competency assessment for robotic-assisted complete mesocolic excision surgery in a simulated setting.

Surgical outcomes of a prospective, phase 2 trial of robotic surgery for resectable right-sided colon cancer (the ROBOCOLO trial).

Aim: We evaluated the safety of robotic surgery for right-sided colon cancer in Japan. Methods: This was a prospective, open-label, single-arm phase II trial conducted at two institutions. Patients ≥20 years old with stage I-III right-sided colon cancer and scheduled for radical resection with ≥D2 lymph node dissection were eligible. The criterion for surgeons was experience performing robot-assisted rectal resection in ≥40 cases. The primary endpoint was the postoperative complication rate ≤30 days after surgery. Results: From August 2021 to February 2023, 42 patients were enrolled; three were excluded, with 39 analyzed as the full analysis set. The median age was 72 years, and the median body mass index was 23.2. The tumor was located in the cecum in 13 cases (33.3%), ascending colon in 20 cases (51.3%), and transverse colon in six cases (15.4%). Ileocolic resection was performed in 17 cases (43.5%) and right hemicolectomy in 22 cases (56.5%), both with D3 lymph node dissection. The median console time was 109 min, and the operative time was 170 min. The mean blood loss was 7.7 mL. Intracorporeal anastomosis was performed in 28 patients (71.8%). There were no conversions and no intraoperative adverse events. The median postoperative stay was 5 days. Postoperative complications occurred in four patients (10.2%; paralytic ileus [n = 3] and pneumonia [n = 1]). All postoperative complications were grade 1 or 2, with no mortalities noted. R0 resection was achieved in all patients. Conclusions: This study demonstrated the safety and feasibility of robotic surgery for right-sided colon cancer.

Early recurrence after complete mesocolic excision for right-sided colon cancer with D3 lymphadenectomy: pattern, risk factors, prognostic impact, and individualized follow-up.

The definition of early recurrence (ER) for right-sided colon cancer patients after complete mesocolic excision (CME) with D3 lymphadenectomy remains unclear. This study aimed to define the optimal time for ER and clarify risk factors for ER and post-recurrence survival (PRS). A total of 578 right-sided colon cancer patients who underwent CME with D3 lymphadenectomy were included. The minimum p value method was used to evaluate theme optimal time of recurrence-free survival to discriminate between ER and late recurrence (LR). Risk factors for ER were determined by a logistics regression model. The PRS was compared between ER and LR. The optimal time to define ER was 15 months (P = 1.8697E-7). 93 patients developed tumor recurrence, 46 patients had ER (≤15 months) and 47 patients had LR (>15 months). Preoperative serum CA19-9 > 37 U/mL (OR = 3.185, P = 0.001), pathological N+ stage (OR = 3.042, P = 0.027), and lymphovascular invasion (OR = 2.182, P = 0.027) were identified as independent risk factors associated with ER. Age > 75 years (HR = 1.828, P = 0.040), pathological N2 stage (HR = 1.850, P = 0.009), multiple sites of recurrence (HR = 1.680, P = 0.024), and time to recurrence ≤15 months (HR = 2.018, P = 0.043) were significantly associated with worse PRS in patients with recurrence. 15 months was the optimal time to distinguish ER and LR. ER was associated with a poor PRS. Elevated preoperative serum CA19-9 level, pathological N+ stage, and lymphovascular invasion were significantly predictive of ER.

Complete mesocolic excision and extended lymphadenectomy: Where should we stand?

Debate regarding the risks and merits of complete mesocolic excision and extended lymphadenectomy is ongoing, particularly for right-sided colon cancers. In this article, we hope to provide a succinct yet encompassing review of the relevant literature. We posit that complete mesocolic excision with D3 dissection is indicated in select patients with colon cancers, particularly those distal to the cecum.

Complete mesocolic excision for colon cancer: current status and controversies.

According to Hohenberger's original description, complete mesocolic excision for colon cancer involves precise dissection of the avascular embryonic plane between the parietal retroperitoneum and visceral peritoneum of the mesocolon. This ensures mesocolic integrity, access to high ligation of the supplying vessels at their origin and an associated extended lymphadenectomy. Results from centres which have adopted this approach routinely have demonstrated that oncological outcomes can be improved by the rigorous implementation of established principles of cancer surgery. Meticulous anatomical dissection along embryonic planes is a well-established principle of precision cancer surgery used routinely by the specialist colorectal surgeon. Therefore, the real question concerns the need for true central vascular ligation and associated extended (D3) lymphadenectomy or otherwise, particularly along the superior mesenteric vessels when performing a right colectomy. Whether this approach results in improved overall or disease-free survival remains unclear and its role remains controversial particularly given the potential for significant morbidity associated with a more extensive central vascular dissection. Current literature is limited by considerable bias, as well as inconsistent and variable terminology, and the results of established randomized trials are awaited. As a result of the current state of equipoise, various national guidelines have disparate recommendations as to when complete mesocolic excision should be performed if at all. This article aims to review the rationale for and technical aspects of complete mesocolic excision, summarize available short and long term outcome data and address current controversies.

Complete mesocolic excision for right colon cancer: Is D3 lymphadenectomy necessary?

AIM: Although complete mesocolic excision (CME) for colon cancer is oncologically sound, to date, there has been no consensus on the extent of lymphadenectomy in radical right colectomy. This study essentially compared the perioperative and survival outcomes of CME with two templates of lymphadenectomy for right colon cancer. METHOD: This was a propensity matched, retrospective analysis of a single centre, prospectively maintained database of all patients undergoing elective right colectomy for nonmetastatic, biopsy-proven adenocarcinoma from November 2013 to October 2018. CME + D3 was adopted selectively, documented prospectively, and compared with patients undergoing CME + central vascular ligation (CVL). The only technical difference between the groups was the excision of the surgical trunk of Gillot in the CME + D3 group. Postoperative, long-term outcomes and patterns of recurrence were compared between the groups. RESULTS: Of the 244 eligible patients, 88 (36.1%) and 156 (63.9%) underwent CME + D3 and CME + CVL, respectively. Matched groups (72 [CME + D3] vs. 108 [CME + CVL]) showed no difference in histology, tumour grade, postoperative complications, mortality, and hospital stay. CME + D3 was preferentially performed laparoscopically (35.2% vs. 9%), was associated with lower blood loss (215 mL vs. 297 mL, p = 0.001), higher nodal yield (31 vs. 25 nodes, p = 0.003) and a higher incidence of chyle leak (4 vs. 0, p = 0.013). At a median follow-up of more than 57 months, there was no significant difference in local recurrence, disease-free or overall survival. CONCLUSION: In this retrospective study, lymphadenectomy along the superior mesenteric vein, as a component of CME for right colon cancer, offered a higher nodal yield with no improvement in oncological outcome. Dissection of the SMV, over and above a D2 dissection, could therefore be restricted to specialized colorectal units until further studies establish the incremental oncological benefit of this extended lymphadenectomy or define a patient group in whom it is beneficial.

A Randomized Phase III Trial of Complete Mesocolic Excision Compared with Conventional Surgery for Right Colon Cancer: Interim Analysis of a Nationwide Multicenter Study of the Italian Society of Surgical Oncology Colorectal Cancer Network (CoME-in trial).

BACKGROUND: Although complete mesocolic excision (CME) is supposed to be associated with a higher lymph node (LN) yield, decreased local recurrence, and survival improvement, its implementation currently is debated because the evidence level of these data is rather low and still not supported by randomized controlled trials. METHOD: This is a multicenter, randomized, superiority trial (NCT04871399). The 3-year disease-free survival (DFS) was the primary end point of the study. The secondary end points were safety (duration of operation, perioperative complications, hospital length of stay), oncologic outcomes (number of LNs retrieved, 3- and 5-year overall survival, 5-year DFS), and surgery quality (specimen length, area and integrity rate of mesentery, length of ileocolic and middle-colic vessels). The trial design required the LN yield to be higher in the CME group at interim analysis. RESULTS: Interim data analysis is presented in this report. The study enrolled 258 patients in nine referral centers. The number of LNs retrieved was significantly higher after CME (25 vs. 20; p = 0.012). No differences were observed with respect to intra- or post-operative complications, postoperative mortality, or duration of surgery. The hospital stay was even shorter after CME (p = 0.039). Quality of surgery indicators were higher in the CME arm of the study. Survival data still were not available. CONCLUSIONS: Interim data show that CME for right colon cancer in referral centers is safe and feasible and does not increase perioperative complications. The study documented with evidence that quality of surgery and LN yield are higher after CME, and this is essential for continuation of patient recruitment and implementation of an optimal comparison. Trial registration The trial was registered at ClinicalTrials.gov with the code NCT04871399 and with the acronym CoME-In trial.