Complete mesocolic excision versus conventional hemicolectomy in patients with right colon cancer: a systematic review and meta-analysis

Advancing precision, safety, and education in D3 lymph node dissection for right hemicolectomy using mixed reality technology

Right hemicolectomy (RHC) is an important treatment for colorectal cancer. The superior mesenteric artery and superior mesenteric vein are known for their significant vascular variations. This study evaluated the short-term outcomes of integrating Mixed Reality (MR) technology into RHC for the treatment of colorectal cancer. Patients who underwent RHC for clinical stage II or III colon cancer between January 2015 and August 2024 were included. Patients were divided into two groups: the MR (+) group (n = 47), in which MR was used, and the MR (-) group (n = 145), in which MR was not used. MR using SYNAPSE VINCENT, Holoeyes MD, and HoloLens2 was utilized for detailed 3D visualization of the vascular anatomy preoperatively and intraoperatively. Forty-four patients per group were matched via propensity score matching and surgical outcomes were compared. In both groups, approximately 70% of the surgeries were performed by the training surgeon. Compared with the MR (-) group, intraoperative blood loss and hospital stay were decreased, and the number of lymph nodes harvested around the middle colic artery/vein were increased without prolonging the operative time in the MR (+) group. MR in RHC offers surgical precision, safety, enhanced patient recovery, and educational value.

Factor analysis of postsurgical gastroparesis syndrome after right hemicolectomy for colon cancer

The present study aimed to investigate factors influencing postsurgical gastroparesis syndrome (PGS) in patients with right-sided colon cancer. In total, 260 patients who underwent complete mesocolic excision for right-sided colon cancer were included in the present analysis. Among the included patients, 69 underwent open radical right-sided colon resection, 175 underwent laparoscopic radical right-sided colon resection and 16 underwent robot-assisted radical right-sided colon resection. The occurrence of PGS was observed, and both the χ2 test and multivariate regression analysis were conducted to identify influencing factors. Among the 260 patients, 32 experienced PGS, with an incidence rate of 12.3%. Univariate analysis demonstrated that age, perioperative blood glucose levels, self-rated anxiety scale scores and surgical approach were significantly associated with PGS (P<0.05), whereas sex, surgical duration, diabetes and perioperative albumin levels were not significant factors (P>0.05). Multivariate logistic regression analysis showed that age >70 years, perioperative blood glucose ≥11.1 mmol/l, a self-rating anxiety scale score ≥50 and radical extended right-sided colon resection were risk factors for PGS occurrence. In conclusion, the occurrence of PGS in patients with right-sided colon cancer was revealed to be associated with age, perioperative blood glucose levels, self-rated anxiety scale scores and surgical approach.

The effect of combined head and tail approach during laparoscopic D3 lymph node dissection on pain severity and complications in patients with right colon cancer

OBJECTIVE

To examine the impact of a combined craniocaudal approach on pain and complications during laparoscopic D3 lymph node dissection in clients diagnosed with right colon cancer (RCC).

METHODS

100 RCC patients were divided into Group A and Group B. Both groups underwent laparoscopic D3 lymph node dissection, with Group A undergoing an intermediate approach and Group B undergoing a combined head and tail approach. Two groups of patients' perioperative (surgical time, intraoperative blood loss, number of lymph node dissection) indicators, postoperative recovery (postoperative exhaust time, postoperative hospital stay, drainage tube removal time) indicators, perioperative pain level (VAS scores 1, 3, and 5 days following surgery), and incidence of complications (vascular injury, intestinal obstruction, anastomotic bleeding, incision infection), and the therapeutic efficacy [CEA, CA19-9] indicators were compared.

RESULTS

Clients in the B team had substantially shorter operating times and considerably fewer intraoperative hemorrhage than those in the A team. The VAS grades of clients in the B team were considerably lower than those in the A team the day following surgery. Clients in the B team experienced vascular injury at a substantially lower rate than those in the A team. The overall incidence rate of problems did not differ statistically significantly between the A team and the B team. Following therapy, teams A and B's CEA and CA19-9 levels were considerably lower than those of the same team prior to therapy.

CONCLUSION

Combined craniocaudal technique can significantly reduce intraoperative bleeding, postoperative pain, and the risk of sequelae from vascular injuries.

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.

Short-term morbidity and mortality after right hemicolectomy: an update of national performance in the Netherlands

AIM

The purpose of this Dutch retrospective population-based study was to evaluate how short-term outcomes and inter-hospital variability after right hemicolectomy for colon cancer have evolved between 2012 and 2020.

METHOD

Patients who underwent right hemicolectomy for primary solitary colon cancer between 1 January 2012 and 31 December 2020 and were registered in the Dutch Colorectal Audit were included. Surgical characteristics and outcomes were assessed during three time periods (2012-2014, 2015-2017, 2018-2020). Complications and mortality were the primary outcomes, and reintervention, readmission and length of stay secondary outcomes.

RESULTS

In total, 29 274 patients were included. Significant increase in minimally invasive surgery (51.1% 2012-2014, 73.2% 2015-2017, 85.0% 2018-2020), increase in conversion (6.6%, 7.8%, 9.1%, P < 0.001) and decrease in acute/urgent resections (15.9%, 11.7%, 10.9%, P < 0.001) were found. The overall complication rate was slightly lower in the third period (30.9%, 30.6%, 28.8%, P = 0.004), primarily because of decreasing non-surgical complications (19.7%, 20.6%, 17.6%, P < 0.001), while surgical complications remained unchanged (17.5%, 18.3%, 18.2%, P = 0.277). Postoperative mortality was 3.4%, 2.3% and 3.5%, respectively. Reintervention rate slightly decreased (9.4%, 8.3%, 8.6%, P < 0.001). The proportion of patients admitted for more than 6 days decreased over time (54.3%, 42.4%, 34.3%, P < 0.001), with an increase in readmission rate (7.4%, 6.8%, 9.3%, P < 0.001). Inter-hospital variability decreased over time for complications, length of stay and conversion.

CONCLUSION

This study shows a national decreasing inter-hospital variability in clinical outcomes after right hemicolectomy and a decrease in postoperative complications. Despite increasing use of laparoscopy, surgical complications and mortality remained stable over time.

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.

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.

Laparoscopic D3 right hemicolectomy with intracorporeal anastomosis

Complete mesocolic excision (CME) with D3 lymphadenectomy for colon cancer has been shown to improve overall as well as disease-free survival compared to conventional right hemicolectomy. Performing a laparoscopic CME/D3 right hemicolectomy with intracorporeal anastomosis (ICA) can be technically demanding even for experienced operators. Here, we present a systematic, standardized approach to the surgery.

Surgical treatment of right colon cancer

The study aimed to perform a systematic review of the literature on surgical treatment for right colon cancer (RCC) with complete mesocolic excision (CME) and D2/D3 lymph node dissection (LND). Material and Methods. A literature review was performed for studies published between 2013 and 2023 by the online resources from the official Web sites of the societies/panels and PubMed database. Sources included guidelines, meta-analyses, randomized and nonrandomized clinical studies, guidelines by European Society of Medical Oncology, the Japanese Society for Cancer of the Colon and Rectum, and the National Comprehensive Cancer Network, Russian clinical guidelines. Results. CME significantly improved both immediate and long-term treatment results, which was confirmed by numerous meta-analyses. The extent of LND remains one of the most controversial issues in RCC. For many Asian surgeons, D3 LND is the standard procedure for the treatment of RCC, whereas the European approach is more conservative and apical lymph node dissection is not mandatory. There are also large differences in understanding the extent of D3 LND in RCC. Most surgeons understand this term as dissection of adipose tissue along the anterior and lateral surface of the superior mesenteric vein, however, there are authors who perform circular dissection along the superior mesenteric vessels, considering this extent of surgery to be the most radical. Conclusion. It is necessary to standardize methods and effective criteria for quality control of CME for RCC and LND. In this case, external independent assessment of the quality of surgical intervention is important. There is also currently a growing number of studies in which intraoperative fluorescence imaging makes it possible to better visualize the location of the apical lymph nodes and individualize LND.

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.

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.

Challenging case of deficient mismatch repair right-sided locally advanced adenocarcinoma of the ascending colon with duodenal involvement: A case report including step-by-step video of operation

INTRODUCTION AND IMPORTANCE

Irresectable colon cancer presents a complex clinical challenge. Neoadjuvant immunotherapy has shown potential in improving resectability. Additionally, advancements in surgical techniques, including complete mesocolic excision (CME) with central vascular ligation (CVL), have contributed to better outcomes for right-sided colon cancer. This case report aims to demonstrate the successful laparoscopic resection of initial appearing irresectable colon cancer with suspected duodenal involvement.

CASE PRESENTATION

A 70-year-old female presented with an irresectable mismatch repair deficient (dMMR) adenocarcinoma of the ascending colon with suspected duodenal ingrowth. Neoadjuvant treatment with pembrolizumab and ataluren resulted in a significant response, allowing for surgical resection. A laparoscopic right hemicolectomy with CME, including CVL, intracorporeal anastomosis and extraction through a Pfannenstiel incision, was performed. Additionally, the serosal layer of the duodenum was shaved after observing the absence of intraluminal invasion. Postoperatively, transient gastroparesis occurred, but overall outcomes were favourable.

CLINICAL DISCUSSION

This case emphasizes the potential of immunotherapy in improving resectability for irresectable dMMR colon cancer with suspected involvement of surrounding organs. The combination of neoadjuvant therapy and advanced surgical techniques, such as CME with CVL, shows promise in achieving favourable clinical outcomes. However, further studies are needed to validate the effectiveness and safety of this combined approach in a larger cohort of patients.

CONCLUSION

The successful laparoscopic resection of initially irresectable dMMR colon cancer with duodenal involvement, following neoadjuvant immunotherapy, demonstrated promising outcomes. This case advocates for further exploration of neoadjuvant treatments' efficacy, coupled with advanced surgical techniques, in managing locally advanced right-sided colon cancer.

Long-term oncological outcomes of robotic versus laparoscopic approaches for right colon cancer: a systematic review and meta-analysis

PURPOSE

The short-term outcomes of robotic right hemicolectomy for right colon cancer have been extensively studied in comparison to conventional laparoscopic right hemicolectomy. However, the long-term oncological outcomes of the two approaches have not been investigated, except in single-center retrospective studies. Therefore, this meta-analysis aimed to investigate the long-term oncological outcomes of robotic right hemicolectomy compared with those of laparoscopic right hemicolectomy for right colon cancer.

METHODS

We searched PubMed, EMBASE, and Cochrane Library for studies comparing robotic right hemicolectomy with conventional laparoscopic right hemicolectomy for right colon cancer from the date of database inception to August 2022. For survival data extraction, hazard ratios (HRs) with 95% confidence intervals (CI) were calculated using random- or fixed-effects models from the Kaplan-Meier survival curves in the included studies. All calculations and statistical tests were performed using Review Manager software, version 5.4.

RESULTS

A total of 523 patients (robotic right hemicolectomy, 230; laparoscopic right hemicolectomy, 293) from five studies were included in this meta-analysis. There were no significant differences in patient characteristics between the two groups. In terms of pathological characteristics, TNM stage was not different and revealed no differences in the number of harvested lymph nodes even though a larger number of lymph nodes were harvested in the robotic group in one study. Pooled analyses demonstrated no significant difference in disease-free survival (HR 0.72, 95% CI 0.46-1.13, p = 0.15) and overall survival (HR 0.73, 95% CI 0.48-1.13, p = 0.16) between robotic and laparoscopic right hemicolectomy for right colon cancer.

CONCLUSION

Robotic right hemicolectomy for right colon cancer is comparable with conventional laparoscopic right hemicolectomy in terms of long-term oncological survival. More prospective, multicenter, randomized trials are necessary to determine the oncologic safety of robotic right hemicolectomy.

Complete mesocolic excision versus standard resection for colon cancer: a systematic review and meta-analysis of perioperative safety and an evaluation of the use of a robotic approach

PURPOSE

Complete mesocolic excision (CME) has been associated with improved oncological outcomes in treatment of colon cancer. However, widespread adoption is limited partly because of the technical complexity and perceived risks of the approach. The aim of out study was to evaluate the safety of CME compared to standard resection and to compare robotic versus laparoscopic approaches.

METHODS

Two parallel searches were undertaken in MEDLINE, Embase and Web of Science databases 12 December 2021. The first was to evaluate IDEAL stage 3 evidence to compare complication rates as a surrogate marker of perioperative safety between CME and standard resection. The second independent search compared lymph node yield and survival outcomes between minimally invasive approaches.

RESULTS

There were four randomized control trials (n = 1422) comparing CME to standard resection, and three studies comparing laparoscopic (n = 164) to robotic (n = 161) approaches. Compared to standard resection, CME was associated with a reduction in Clavien-Dindo grade 3 or higher complication rates (3.56% vs. 7.24%, p = 0.002), reduced blood loss (113.1 ml vs. 137.6 ml, p < 0.0001) and greater mean lymph node harvest (25.6 vs. 20.9 nodes, p = 0.001). Between the robotic and laparoscopic groups, there were no significant differences in complication rates, blood loss, lymph node yield, 5-year disease-free survival (OR 1.05, p = 0.87) and overall survival (OR 0.83, p = 0.54).

CONCLUSIONS

Our study demonstrated improved safety with CME. There was no difference in safety or survival outcomes between robotic and laparoscopic CME. The advantage of a robotic approach may lie in the reduced learning curve and an increased penetration of minimally invasive approach to CME. Further studies are required to explore this.

PROSPERO ID

CRD42021287065.

Complete mesocolic excision for right hemicolectomy: an updated systematic review and meta-analysis

PURPOSE

Complete mesocolic excision improves lymphadenectomy for right hemicolectomy and respects the embryological planes. However, its effect on cancer-free and overall survival is questioned. Therefore, we aimed to determine the potential benefits of the technique by performing a systematic review of the literature and meta-analysis of the available evidence.

METHODS

Web of Science, PubMed/Medline, and Embase were searched on February 22, 2023. Original studies on short- and long-term oncological outcomes of adult patients undergoing right hemicolectomy with complete mesocolic excision as a treatment for primary colon cancer were considered for inclusion. Outcomes were extracted and pooled using a model with random effects.

RESULTS

A total of 586 publications were identified through database searching, and 18 from citation searching. Exclusion of 552 articles left 24 articles for inclusion. Meta-analysis showed that complete mesocolic excision increased the lymph node harvest (5 studies, 1479 patients, MD 9.62, 95% CI 5.83-13.41, p > 0.0001, I2 84%), 5-year overall survival (5 studies, 2381 patients, OR 1.88, 95% CI 1.14-3.09, p = 0.01, I2 66%), 5-year disease-free survival (4 studies, 1376 patients, OR 2.21, 95% CI 1.51-3.23, p < 0.0001, I2 0%) and decreased the incidence of local recurrence (4 studies, 818 patients, OR 0.27, 95% CI 0.09-0.79, p = 0.02, I2 0%) when compared to standard right hemicolectomy. Perioperative morbidity was similar between the techniques (8 studies, 3899 patients, OR 1.04, 95% CI 0.89-1.22, p = 0.97, I2 0%).

CONCLUSION

Meta-analysis of observational and randomised studies showed that right hemicolectomy with complete mesocolic excision for primary right colon cancer improves oncologic results without increasing morbidity/mortality. These results need to be confirmed by high-quality evidence and randomised trials in selected patients to assess who may benefit from the procedure.

Efficacy and Feasibility of Complete Mesocolic Excision with Central Vascular Ligation in Complicated Colorectal Cancer

Complete mesocolic excision (CME) with central vascular ligation (CVL) involves sharp dissection through the embryological planes. However, it may be associated with high mortalities and morbidities especially in colorectal emergencies. This study aimed to investigate the outcomes of CME with CVL in complicated colorectal cancers (CRCs). This was a retrospective study of emergency CRC resection in a tertiary center between March 2016 and November 2018. A total of 46 patients, with a mean age of 51 years, underwent an emergency colectomy for cancer (males, 26 [56.5%]; females, 20 [43.5%]). CME with CVL was performed for all patients. The mean operative time and blood loss were 188 min and 397 mL, respectively. Only five (10.8%) patients presented with burst abdomen, whereas only three (6.5%) presented with anastomotic leakage. The mean length of vascular tie was 8.7 cm, and the mean number of harvested lymph nodes (LNs) was 21.2. Emergency CME with CVL is a safe and feasible technique when performed by a colorectal surgeon and will result in obtaining a superior specimen with a large number of LNs.

Surgical and oncological outcomes of laparoscopic right hemicolectomy (D3 + CME) for colon cancer: A prospective single-center cohort study

BACKGROUND

Complete mesocolic excision (CME) or D3 lymphadenectomy led to survival benefits for locally advanced right colon cancer, but with vague definitions in anatomy and debated surgical hazard in clinic. Aiming to achieve a precise definition of it in anatomy, we proposed laparoscopic right hemicolectomy (D3 + CME) as a novel procedure for colon cancer. However, the surgical and oncological results of this procedure in clinic were uncertain.

METHODS

We performed a cohort study involving prospective data collected from a single-center in China. Data from all patients who underwent right hemicolectomy between January 2014 and December 2018 were included. We compared the surgical and oncological outcomes between D3 + CME and conventional CME.

RESULTS

After implementation of exclusion criteria, a total of 442 patients were included. D3 + CME group performed better in lymph nodes harvested (25.0 [17.0, 33.8] vs. 18.0 [14.0, 25.0], P < 0.001) and the proportion of intraoperative blood loss ≥ 50 mL (31.7% vs. 51.8%, P < 0.001); no significant difference was observed in the complication rates between two groups. Kaplan-Meier analysis demonstrated that a better cumulative 5-year disease-free survival (91.3% vs. 82.2%, P = 0.026) and a better cumulative 5-year overall survival (95.2% vs. 86.1%, P = 0.012) were obtained in the D3 + CME group. Multivariate COX regression revealed that D3 + CME was an independent protective factor for disease-free survival (P = 0.026).

CONCLUSION

D3 + CME could improve surgical and oncological outcomes simultaneously for right colon cancer compared to conventional CME. Large-scale randomized controlled trials were further required to confirm this conclusion, if possible.

Simultaneous, Multi-Channel, Near-Infrared Fluorescence Visualization of Mesenteric Lymph Nodes Using Indocyanine Green and Methylene Blue: A Demonstration in a Porcine Model

Near-infrared fluorescence (NIRF) image-guided surgery is a useful tool that can help reduce perioperative complications and improve tissue recognition. Indocyanine green (ICG) dye is the most frequently used in clinical studies. ICG NIRF imaging has been used for lymph node identification. However, there are still many challenges in lymph node identification by ICG. There is increasing evidence that methylene blue (MB), another clinically applicable fluorescent dye, can also be useful in the intraoperative fluorescence-guided identification of structures and tissues. We hypothesized that MB NIRF imaging could be used for lymph node identification. The aim of this study was to evaluate the feasibility of intraoperative lymph node fluorescence detection using intravenously (IV) administered MB and compare it to ICG via a camera that has two dedicated near-infrared (NIR) channels. Three pigs were used in this study. ICG (0.2 mg/kg) was administered via a peripheral venous catheter followed by immediate administration of MB (0.25 mg/kg). NIRF images were acquired as video recordings at different time points (every 10 min) over an hour using the QUEST SPECTRUM® 3 system (Quest Medical Imaging, Middenmeer, The Netherlands), which has two dedicated NIR channels for simultaneous intraoperative fluorescence guidance. The 800 nm channel was used to capture ICG fluorescence and the 700 nm channel was used for MB. The target (lymph nodes and small bowel) and the background (vessels-free field of the mesentery) were highlighted as the regions of interest (ROIs), and corresponding fluorescence intensities (FI) from these ROIs were measured. The target-to-background ratio (TBR) was then computed as the mean FI of the target minus the mean FI of the background divided by the mean FI of the background. In all included animals, a clear identification of lymph nodes was achieved at all time points. The mean TBR of ICG in lymph nodes and small bowel was 4.57 ± 1.00 and 4.37 ± 1.70, respectively for the overall experimental time. Regarding MB, the mean TBR in lymph nodes and small bowel was 4.60 ± 0.92 and 3.27 ± 0.62, respectively. The Mann-Whitney U test of the lymph node TBR/small bowel TBR showed that the TBR ratio of MB was statistically significantly higher than ICG. The fluorescence optical imaging technology used allows for double-wavelength assessment. This feasibility study proves that lymph nodes can be discriminated using two different fluorophores (MB and ICG) with different wavelengths. The results suggest that MB has a promising potential to be used to detect lymphatic tissue during image-guided surgery. Further preclinical trials are needed before clinical translation.

Robot-assisted versus laparoscopic short- and long-term outcomes in complete mesocolic excision for right-sided colonic cancer: a systematic review and meta-analysis

BACKGROUND

Complete mesocolic excision (CME) surgery is increasingly implemented for the resection of right-sided colonic cancer, possibly resulting in improved 5-year overall and disease-free survival compared to non-CME surgery. However, it is not clear what surgical platform should be used. The aim of this study was to compare the following outcomes between robot-assisted and laparoscopic CME-surgery for right-sided colonic cancer: (i) short-term clinical outcomes, (ii) pathological specimen quality, and (iii) long-term oncological outcomes.

METHODS

Medline, Embase, and Cochrane Database of Systematic Reviews were searched from inception until August 2021. Pooled proportions were calculated by applying the inverse variance method. Heterogeneity was explored by I-square and supplemented by sensitivity- and meta-regression analyses. The risk of bias was evaluated by either MINORS or Cochrane's risk-of-bias tool (RoB 2).

RESULTS

Fifty-five studies with 5.357 patients (740 robot-assisted and 4617 laparoscopic) were included in the meta-analysis. Overall postoperative morbidity was 17% [95% CI (14-20%)] in the robot-assisted group and 13% [95%CI (12-13%)] in the laparoscopic group. Robot-assisted CME was associated with a shorter hospital stay, lower intraoperative blood loss, a higher amount of harvested lymph nodes, and better 3-year oerall and disease-free survival. MINORS and RoB2 indicated a serious risk of bias across studies included.

CONCLUSIONS

This review which includes predominantly non-randomized studies suggests a possible advantage of the robot-assisted CME compared with a laparoscopic technique for several short-term outcomes.

Complete mesocolic excision for right colonic cancer: prospective multicentre study

BACKGROUND

Complete mesocolic excision (CME) for right colonic cancer is a more complex operation than standard right hemicolectomy but evidence to support its routine use is still limited. This prospective multicentre study evaluated the effect of CME on long-term survival in colorectal cancer centres in Germany (RESECTAT trial). The primary hypothesis was that 5-year disease-free survival would be higher after CME than non-CME surgery. A secondary hypothesis was that there would be improved survival of patients with a mesenteric area greater than 15 000 mm2.

METHODS

Centres were asked to continue their current surgical practices. The surgery was classified as CME if the superior mesenteric vein was dissected; otherwise it was assumed that no CME had been performed. All specimens were shipped to one institution for pathological analysis and documentation. Clinical data were recorded in an established registry for quality assurance. The primary endpoint was 5-year overall survival for stages I-III. Multivariable adjustment for group allocation was planned. Using a primary hypothesis of an increase in disease-free survival from 60 to 70 per cent, a sample size of 662 patients was calculated with a 50 per cent anticipated drop-out rate.

RESULTS

A total of 1004 patients from 53 centres were recruited for the final analysis (496 CME, 508 no CME). Most operations (88.4 per cent) were done by an open approach. Anastomotic leak occurred in 3.4 per cent in the CME and 1.8 per cent in the non-CME group. There were slightly more lymph nodes found in CME than non-CME specimens (mean 55.6 and 50.4 respectively). Positive central mesenteric nodes were detected more in non-CME than CME specimens (5.9 versus 4.0 per cent). One-fifth of patients had died at the time of study with recorded recurrences (63, 6.3 per cent), too few to calculate disease-free survival (the original primary outcome), so overall survival (not disease-specific) results are presented. Short-term and overall survival were similar in the CME and non-CME groups. Adjusted Cox regression indicated a possible benefit for overall survival with CME in stage III disease (HR 0.52, 95 per cent c.i. 0.31 to 0.85; P = 0.010) but less so for disease-free survival (HR 0.66; P = 0.068). The secondary outcome (15 000 mm2 mesenteric size) did not influence survival at any stage (removal of more mesentery did not alter survival).

CONCLUSION

No general benefit of CME could be established. The observation of better overall survival in stage III on unplanned exploratory analysis is of uncertain significance.

Computer-Assisted Differentiation between Colon-Mesocolon and Retroperitoneum Using Hyperspectral Imaging (HSI) Technology

Complete mesocolic excision (CME), which involves the adequate resection of the tumor-bearing colonic segment with "en bloc" removal of its mesocolon along embryological fascial planes is associated with superior oncological outcomes. However, CME presents a higher complication rate compared to non-CME resections due to a higher risk of vascular injury. Hyperspectral imaging (HSI) is a contrast-free optical imaging technology, which facilitates the quantitative imaging of physiological tissue parameters and the visualization of anatomical structures. This study evaluates the accuracy of HSI combined with deep learning (DL) to differentiate the colon and its mesenteric tissue from retroperitoneal tissue. In an animal study including 20 pig models, intraoperative hyperspectral images of the sigmoid colon, sigmoid mesentery, and retroperitoneum were recorded. A convolutional neural network (CNN) was trained to distinguish the two tissue classes using HSI data, validated with a leave-one-out cross-validation process. The overall recognition sensitivity of the tissues to be preserved (retroperitoneum) and the tissues to be resected (colon and mesentery) was 79.0 ± 21.0% and 86.0 ± 16.0%, respectively. Automatic classification based on HSI and CNNs is a promising tool to automatically, non-invasively, and objectively differentiate the colon and its mesentery from retroperitoneal tissue.

Qualitative umbrella review of systematic reviews on complete mesocolic excision for colon cancer

BACKGROUND

Complete mesocolic excision (CME) of colon cancer with extended lymphadenectomy was suggested to improve radical resection of colon cancer. This comprehensive review aimed to assess the current literature for the outcomes of CME of colon cancer through an appraisal of the findings of published systematic reviews and meta-analyses.

METHODS

A systematic literature review searching for the studies that assessed the outcome of CME of colon cancer was conducted. Electronic databases were queried from 2009 through November 2020. The main objectives of this review were to illustrate the technical aspects and outcome of CME and to summarize the findings of the published systematic reviews.

RESULTS

Thirteen systematic reviews were retrieved. All reviews found CME to provide longer bowel, larger area of mesentery resected, and more lymph nodes (LNs) retrieved than standard colectomy. All systematic reviews except two found similar complication rates between CME and standard colectomy. Four systematic reviews documented the survival benefit of CME in regards to improved overall and disease-free survival. Using the laparoscopic approach for CME did not compromise the oncologic outcomes of the procedures, yet was associated with less intraoperative blood loss, faster recovery, and potential survival benefits.

CONCLUSIONS

CME is associated with better specimen quality, more LNs clearance, and potential survival benefits compared to standard colectomy. However, the lack of robust data from well-designed multicenter randomized trials may prevent drawing firm conclusions on the oncologic benefits of CME. Further high-quality studies are needed before recommending CME as the standard of care for colon cancer.

Pattern of recurrence and survival after D2 right colectomy for cancer: is there place for a routine more extended lymphadenectomy?

BACKGROUND

Conventional Right Colectomy with D2 lymphadenectomy (RC-D2) currently represent the most common surgical treatment of right-sided colon cancer (RCC). However, whether it should be still considered a standard of care, or replaced by a routine more extended D3 lymphadenectomy remains unclear. In the present study, we aim to critically review the patterns of relapse and the survival outcomes obtained from our 11-year experience of RC-D2.

METHODS

Clinical data of 489 patients who underwent RC-D2 for RCC at two centres, from January 2009 to January 2020, were retrospectively reviewed. Patients with synchronous distant metastases and/or widespread nodal involvement at diagnosis were excluded. Post-operative clinical-pathological characteristics and survival outcomes were evaluated including the pattern of disease relapse.

RESULTS

We enrolled a total of 400 patients with information follow-up. Postoperative morbidity was 14%. The median follow-up was 62 months. Cancer recurrence was observed in 55 patients (13.8%). Among them, 40 patients (72.7%) developed systemic metastases, and lymph-node involvement was found in 7 cases (12.8%). None developed isolated central lymph-node metastasis (CLM), in the D3 site. The estimated 3- and 5-year relapse-free survival were 86.1% and 84.4%, respectively. The estimated 3- and 5-year cancer-specific OS were 94.5% and 92.2%, respectively.

CONCLUSIONS

The absence of isolated CLM, as well as the cancer-specific OS reported in our series, support the routine use of RC-D2 for RCC. However, D3 lymphadenectomy may be recommended in selected patients, such as those with pre-operatively known CLM, or with lymph-node metastases close to the origin of the ileocolic vessels.

Lymph node yield in the pathological staging of resected nonmetastatic colon cancer: The more the better?

INTRODUCTION

Guidelines recommend regional lymphadenectomy with a lymph node yield (LNY) of at least 12 lymph nodes (LN) for adequate colon cancer (CC) staging. LNY ≥22LN may improve survival, especially in right-sided CC [Lee et al., Surg Oncol, 27(3), 2018]. This multicentric retrospective cohort study evaluated the impact of LNY and tumor laterality on CC staging and survival.

MATERIALS AND METHODS

Patients with stage I-III CC that underwent surgery from 2012 to 2018 were grouped according to LNY: <22 and ≥ 22. Primary outcomes were LN positivity (N+ rate) and disease-free survival (DFS). Overall survival (OS) was the secondary outcome. Exploratory analyses were performed for laterality and stage.

RESULTS

We included 795 patients (417 < 22LN, 378 ≥ 22LN); 53% had left-sided CC and 29%/37%/38% had stage I/II/III tumors. There was no association between LNY ≥22LN and N+ rate after adjustment for grade, T stage, lymphovascular invasion (LVI) and perineural invasion; a trend for a higher N+ rate in left-sided CC was identified (interaction p = 0.033). With a median follow-up of 63.6 months for DFS and 73.2 months for OS, 254 patients (31.9%) relapsed and 207 (26.0%) died. In multivariate analysis adjusted for age, ASA score, laparoscopic approach, T/N stage, mucinous histology, LVI and adjuvant chemotherapy, LNY ≥22LN was significantly associated with both DFS (HR 0.75, p = 0.031) and OS (HR 0.71, p = 0.025). Restricted cubic spline analysis showed a more significant benefit for right-sided CC.

CONCLUSION

LNY ≥22LN was associated with longer DFS and OS in patients with operable CC, especially for right-sided CC.

Reliability and Educational Value of YouTube Videos of Complete Meso-Colic Excision With Right Hemicolectomy in the COVID-19 Pandemic

Aim: To investigate the reliability and educational value of YouTube videos of minimally invasive complete mesocolic excision with right hemicolectomy procedures.

Materials and methods: We searched YouTube with the terms “Laparoscopic and Robotic Complete Mesocolic Excision with Right Hemicolectomy” on January 12, 2021. To assess the reliability of the videos, we evaluated nine steps in each video and scored the videos based on the key steps they contained. The videos were divided into three groups according to the source of the upload. The total number of views, length, time since upload, and the number of likes, dislikes, and comments were recorded for each video. Narration, the use of descriptive subtitles, and the upload status by an expert surgeon were also examined.

Results: Sixty-eight videos were included in the study. A positive significant correlation was identified between the comprehensiveness score (CS) and the number of views (p=0.025). The CSs of the videos accessed from academic channels, as well as those accessed from journals, congress, and association channels, recorded higher CSs than those obtained from the personal channels of consultants (p=0.003). It was also found that CSs were higher in the videos of expert surgeons (p<0.001) and narrated videos (p<0.001).

Conclusion: Not all YouTube videos on this subject have reliability and educational value. Surgical videos on YouTube may be evaluated by a video review commission formed by academic institutions, surgical associations, or expert surgeons, and videos suitable for education could be brought together and published via a free channel.

Reconstructing topography and extent of injury to the superior mesenteric artery plexus in right colectomy with extended D3 mesenterectomy: a composite multimodal 3-dimensional analysis

Background

Superior mesenteric artery plexus (SMAP) injury is reported to cause postoperative intractable diarrhea after pancreatic/colonic surgery with extended lymphadenectomy. This study aims to describe the SMAP microanatomy and extent of injury after right colectomy with extended D3 mesenterectomy for cancer.

Methods

Three groups (I) anatomical dissection, (II) postmortem histology, and (III) surgical specimen histology were included. Nerve count and area were compared between groups II and III and paravascular sheath thickness between groups I and II. 3D models were generated through 3D histology, nanoCT scanning, and finally through 3D printing.

Results

A total of 21 specimens were included as follows: Group (I): 5 (3 females, 80–93 years), the SMAP is a complex mesh surrounding the superior mesenteric artery (SMA), branching out, following peripheral arteries and intertwining between them, (II): 7 (5 females, 71–86 years), nerve count: 53 ± 12.42 (38–68), and area: 1.84 ± 0.50 mm2 (1.16–2.29), and (III): 9 (5 females, 55–69 years), nerve count: 31.6 ± 6.74 (range 23–43), and area: 0.889 ± 0.45 mm2 (range 0.479–1.668). SMAP transection injury is 59% of nerve count and 48% of nerve area at middle colic artery origin level. The median values of paravascular sheath thickness decreased caudally from 2.05 to 1.04 mm (anatomical dissection) and from 2.65 to 1.17 mm (postmortem histology). 3D histology models present nerve fibers exclusively within the paravascular sheath, and lymph nodes were observed only outside. NanoCT-derived models reveal oblique nerve fiber trajectories with inclinations between 35° and 55°. Two 3D-printed models of the SMAP were also achieved in a 1:2 scale.

Conclusion

SMAP surrounds the SMA and branches within the paravascular sheath, while bowel lymph nodes and vessels lie outside. Extent of SMAP injury on histological slides (transection only) was 48% nerve area and 59% nerve count. The 35°–55° inclination range of SMAP nerves possibly imply an even larger injury when plexus excision is performed (lymphadenectomy). Reasons for later improvement of bowel function in these patients can lie in the interarterial nerve fibers between SMA branches.

Laparoscopic versus open colectomy for locally advanced T4 colonic cancer: meta-analysis of clinical and oncological outcomes

BACKGROUND

The aim of this study was to review the early postoperative and oncological outcomes after laparoscopic colectomy for T4 cancer compared with open surgery.

METHOD

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched for any relevant clinical study comparing laparoscopic and open colectomy as treatment for T4 colonic cancer. The risk ratio (RR) with 95 per cent c.i. was calculated for dichotomous variables, and the mean difference (m.d.) with 95 per cent confidence interval for continuous variables. Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was implemented for assessing quality of evidence (QoE).

RESULTS

Twenty-four observational studies (21 retrospective and 3 prospective cohort studies) were included, analysing a total of 18 123 patients: 9024 received laparoscopic colectomy and 9099 underwent open surgery. Laparoscopic colectomy was associated with lower rates of mortality (RR 0.48, 95 per cent c.i. 0.41 to 0.56; P < 0.001; I2 = 0 per cent, fixed-effect model; QoE moderate) and complications (RR 0.61, 0.49 to 0.76; P < 0.001; I2 = 20 per cent, random-effects model; QoE very low) compared with an open procedure. No differences in R0 resection rate (RR 1.01, 1.00 to 1.03; P = 0.12; I2 = 37 per cent, random-effects model; QoE very low) and recurrence rate (RR 0.98, 0.84 to 1.14; P = 0.81; I2 = 0 per cent, fixed-effect model; QoE very low) were found.

CONCLUSION

Laparoscopic colectomy for T4 colonic cancer is safe, and is associated with better clinical outcomes than open surgery and similar oncological outcomes.

Is Laparoscopic Complete Mesocolic Excision and Central Vascular Ligation Really Necessary for All Patients With Right-Sided Colon Cancer?

Colon cancer treatment is on the way to evolution over several decades. The minimally invasive surgery has improved postoperative short-term outcomes. Adjuvant chemotherapy has prolonged the survival of advanced colon cancer patients. Hohenberger proposed the noble concept of complete mesocolic excision (CME) which consists of 3 components: plane surgery, sufficient longitudinal bowel resection, and central vascular ligation (CVL). Mesocolic plane surgery shares the same surgical principle of total mesorectal excision, which is maintaining the intact mesothelial envelope. However, there remain debates about the extent of bowel resection and the level of CVL for maximizing lymph node dissection. There is no solid clinical evidence for the oncological necessity and benefit of extended radical dissection in right hemicolectomy. CME with CVL based on open surgery has been adopted in laparoscopic surgery. So, it is also necessary to look at how the CME could be transformed and successfully implanted in the laparoscopic era. Recent rapid advances in surgical technology and cancer biology are preparing for fundamental changes in cancer surgery. In this study, we reviewed the history, oncological necessity, and compatibility of CME for the right hemicolectomy in the laparoscopic era and outline the new perspectives on the evolution of cancer surgery.

Laparoscopic and open complete mesocolic excision with central vascular ligation for right colonic adenocarcinoma: a retrospective comparative study

BACKGROUND

To examine the outcome of patients treated with complete mesocolic excision (CME) with central vascular ligation (CVL) after conventional and laparoscopic surgery.

METHODS

We retrospectively evaluated stage I-IV colon adenocarcinoma patients treated by the same surgeon (L.M.) from 2013 to 2018. Postoperative complications, recurrences and survival are assessed.

RESULTS

Fifty-one patients (M/F: 24/27) underwent laparoscopic right hemicolectomy with CME (L-CME) or open CME (O-CME) plus CVL. Tumour location was the caecum in 39.2% of cases, the transverse in 23.5%, the hepatic colonic flexure in 21.5%, and the ascending colon in 15.6%. Twenty-four patients underwent L-CME while 27 underwent O-CME. More than 15 harvested lymphnodes are reported in 74.1% of O-CME patients and in 66.7% of L-CME patients (p = 0.562). Postoperative complications occurred in 7 O-CME and 5 L-CME patients, respectively (p = 0.669). Three-year overall survival, including stage IV, was of 75% versus 77.8% for L-CME and O-CME patients, respectively, while for stage I-III, was of 88.9% vs. 80% in L-CME and O-CME, respectively (p = 0.440). The median follow-up was of 2.43 years.

CONCLUSION

CME with CVL is a meticulous, complex but feasible technique. In our experience, oncological results in terms of recurrences and overall survival, after conventional and laparoscopic CME plus CVL, are comparable. Patients with stage I-III colon adenocarcinoma have a better prognostic trend especially when more than 15 lymphnodes are removed. The respect of oncological radicality and the correct indication to minimally invasive surgery are the undiscussed key outcome variables.

Mesenteric closure with polymer-ligating clips after right colectomy with complete mesocolic excision for cancer and mesentery-based ileocolic resection for Crohn's disease

Mesenteric closure following right colectomy remains controversial and, following the advent of laparoscopic surgery, many surgeons do not routinely close the mesentery after colorectal resection. Nevertheless, especially after the introduction of operations such as right colectomy with complete mesocolic excision and ileocolic resections with extensive mesentery removal for Crohn's disease, the wide mesenteric defect resulting from the dissections can certainly expose the patients to complications such as internal hernias or volvuli. In general, mesenteric closure requires intracorporeal suturing. We describe a simple technique for the closure of the mesentery after surgical resection using polymer-ligating clips. This novel technique seems to minimize the time, effort and risk inherent to the procedure, even after large mesenteric excisions.

Snapshots of lymphatic pathways in colorectal cancer surgery using near-infrared fluorescence, in vivo and ex vivo

INTRODUCTION

Indocyanine green (ICG) fluorescence imaging has been used for blood flow assessment in anastomoses in the field of colorectal cancer surgery. However, whether ICG fluorescence is related to the presence of cancer cells in the lymph nodes is unclear. We explored the utilization of ICG fluorescence in colorectal cancer surgery.

MATERIALS AND METHODS

ICG was injected into the submucosa around the tumor before radical resection in colorectal cancer patients. Intraoperatively, near-infrared (NIR) fluorescence was used for lymphatic flow visualization. After specimen removal, harvested lymph nodes were classified as positive or negative based on the detection of fluorescence, followed by pathological examination. ICG distribution on a section of each lymph node was examined by fluorescence microscopy.

RESULTS

Overall, 155 patients underwent real-time NIR fluorescence imaging-guided surgery. Altogether, 1,017 lymph nodes were retrieved from these patients. Metastatic lymph nodes were present in 36 (5.8%) of 622 fluorescence-negative lymph nodes, which was significantly higher than 11 (2.8%) of 395 fluorescence-positive lymph nodes (odds ratio: 2.15, P = 0.03). Fluorescence microscopy of metastatic lymph nodes showed that ICG fluorescence was present in the normal structural region but not in the cancerous region of the lymph nodes. Furthermore, ICG fluorescence was observed in all metastatic lymph nodes, except those with cancer cells occupying >90% of the total area.

CONCLUSIONS

ICG fluorescence detected only the normal parts of the lymph node draining from the peritumoral area and not the cancer tissues. This finding is important for developing appropriate strategies for navigation surgery using NIR fluorescence.

Perspectives for circulating tumor DNA in clinical management of colorectal cancer

Growing evidence has demonstrated that circulating tumor DNA (ctDNA) detection in colorectal cancer might be a promising approach to address current important clinical questions. During chemotherapy for metastatic colorectal cancer, tumor cells acquire potential resistance by generating additional somatic mutations related to therapeutic resistance. ctDNA can capture the tumor landscape, including heterogeneity, which might provide the opportunity for additional treatment options. Moreover, ctDNA detection is advantageous, because it can monitor tumor heterogeneity serially, in a non-invasive manner. ctDNA is considered valid for detecting minimal residual disease after a curable resection. By utilizing ctDNA detection, adjuvant chemotherapy for patients with stage II-III colorectal cancer might be omitted for patients at low risk of recurrence; or conversely, adjuvant chemotherapy might be highly recommended for patients at high risk, based on ctDNA findings. During multidisciplinary treatments for locally advanced rectal cancer, it is essential to monitor the responses to sequential treatments to make appropriate decisions. Currently, these decisions are mainly based on radiological or pathological findings. ctDNA can add value by providing the real-time status of locally advanced rectal cancer. In this review, we summarized the current evidence and discussed future strategies for using ctDNA in the treatment of colorectal cancer.

Chylous ascites in colorectal surgery: A systematic review

BACKGROUND

Chylous ascites is a rare complication in colorectal surgery with limited evidence.

AIM

To systematically review all available evidence to describe the incidence, clinical presentation, risk factors and management strategies.

METHODS

The systematic review was performed through PubMed, MEDLINE, EMBASE and Cochrane and cross-checked up to November 2020. The data collated included: Demographics, indications (benign vs malignant), site of disease, surgical approach, extent of lymphadenectomy, day to and method of diagnosis of chylous ascites and management strategies.

RESULTS

A total of 28 studies were included in the final analysis (426 cases). Patient age ranged from 31 to 89 years. All except one case were performed for malignancy. Of the 426 cases, 195 were right-colonic, 121 left-colonic, 103 pelvic surgeries and 7 others. The majority were diagnosed during the same inpatient stay by recognition of typical drain appearance and increased volume. Three cases were diagnosed during outpatient visits with increased abdominal distention and subsequently underwent paracentesis. Most cases were managed successfully non-operatively (fasting with prolonged drainage, total parenteral nutrition, somatostatin analogues or a combination of these). Only three cases required surgical intervention after failing conservative management and subsequently resolved completely. Risk factors identified include: Right-colonic surgery/ tumour location, extent of lymphadenectomy and number of lymph nodes harvested.

CONCLUSION

Chylous ascites after colorectal surgery is a relatively rare complication. Whilst the majority of cases resolved without surgical intervention, preventative measures should be undertaken such as meticulous dissection and clipping of lymphatics during lymphadenectomy to prevent morbidity.

Complete Mesocolic Excision and D3 Lymphadenectomy versus Conventional Colectomy for Colon Cancer: A Systematic Review and Meta-Analysis

BACKGROUNDS

Previous systematic reviews suggest that the implementation of 'complete mesocolon excision' (CME) for colon tumors entails better specimen quality but with limited long-term outcomes. We performed a meta-analysis to compare the pathological, perioperative, and oncological results of CME with conventional surgery (CS) in primary colon cancer.

METHODS

Embase, MEDLINE and CENTRAL databases were searched using Medical Subject Headings for CME and D3 lymphadenectomy. The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 18,989 patients from 27 studies were included. Postoperative complications were higher in the CME group (relative risk [RR] 1.13, 95% confidence interval [CI] 1.04-1.22, I² = 0%), while no differences were observed in terms of anastomotic leak (I² = 0%) or perioperative mortality (I² = 49%). CME was associated with a higher number of lymph nodes harvested (I² = 95%), distance to high tie (I² = 65%), bowel length (I² = 0%), and mesentery area (I² = 95%). CME also had positive effects on 3- and 5-year overall survival (RR 1.09, 95% CI 1.04-1.15, I² = 88%; and RR 1.05, 95% CI 1.02-1.08, I² = 62%, respectively) and 3-year disease-free survival (RR 1.10, 95% CI 1.04-1.17, I² = 22%), as well as decreased local (RR 0.35, 95% CI 0.24-0.51, I² = 51%) and distant recurrences (RR 0.71, 95% CI 0.60-0.85, I² = 34%).

CONCLUSIONS

Limited evidence suggests that CME improves oncological outcomes with a higher postoperative adverse events rate but no increase in anastomotic leak rate or perioperative mortality, compared with CS.

Complete mesocolic excision and D3 lymphadenectomy with central vascular ligation in right-sided colon cancer: a systematic review of postoperative outcomes, tumor recurrence and overall survival

BACKGROUND

In right-sided colon cancer surgery, currently there is a great deal of discussion and debate regarding complete mesocolic excision (CME) versus conventional right hemicolectomy (CRH) on postoperative outcomes and oncological results. Our aim was to perform a systematic review of the short- and long-term outcomes of CME to standardize surgical approach in patients with right-sided colon cancer.

METHODS

A systematic review was performed examining available data on randomized and non-randomized studies evaluating the role of CME and D3 lymphadenectomy in the treatment of right-sided colon cancer, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards.

RESULTS

After literature search, 919 studies have been recorded, 110 studies underwent full-text reviews and 30 studies met inclusion criteria. The total number of CME procedures was 5931. Postoperative complications was reported in 28 studies with pooled overall complications of 1.88% for CME surgery. Six studies reported 0% of overall postoperative complications and they demonstrated a low incidence of complications following CME procedure. Anastomotic leak was reported in 27 studies with pooled proportion of 0.92% after CME resections. There were 16 papers reporting overall survival following CME procedure, with a mean of 85% of patients survived at 5 years. Mean 5-year overall survival was 93.05% in stage I patients, 89.76% in stage II patients and 79.65% in stage III patients. Local and distant recurrence were included in 21 studies, reporting tumor recurrence rate of 12.25% following CME. 5-year tumor recurrence was 5.8% in stage I patients, 7.68% in stage II patients and 15.69% in stage III patients.

CONCLUSIONS

CME does not increase the risk of postoperative complications and significantly improves the long-term oncological impact. Prospective multicentre studies results are needed to verify if CME could be considered standard surgery for right colon cancer.