Implementing complete mesocolic excision for colon cancer - mission completed?

Defining distal splenopancreatectomy by the mesopancreas

BACKGROUND

The implementation of the pathologic CRM (circumferential resection margin) staging system for pancreatic head ductal adenocarcinomas (hPDAC) resulted in a dramatic increase of R1 resections at the dorsal resection margin, presumably because of the high rate of mesopancreatic fat (MP) infiltration. Therefore, mesopancreatic excision (MPE) during pancreatoduodenectomy has recently been promoted and has demonstrated better local disease control, fueling the discussion of neoadjuvant downsizing regimes in MP + patients. However, it is unknown to what extent the MP is infiltrated in patients with distal pancreatic (tail/body) carcinomas (dPDAC). It is also unknown if the MP infiltration status affects surgical margin control in distal pancreatectomy (DP). The aim of our study was to histopathologically analyze MP infiltration and elucidate the influence of resection margin clearance on recurrence and survival in patients with dPDAC. Furthermore, the results were compared to a collective receiving MPE for hPDAC.

METHOD

Clinicopathological and survival parameters of 295 consecutive patients who underwent surgery for PDAC (n = 63 dPDAC and n = 232 hPDAC) were evaluated. The CRM evaluation was performed in a standardized fashion and the specimens were examined according to the Leeds pathology protocol (LEEPP). The MP area was histopathologically evaluated for cancerous infiltration.

RESULTS

In 75.4% of dPDAC patients the MP fat was infiltrated by vital tumor cells. The rates of MP infiltration and R0CRM- resections were similar between dPDAC and hPDAC patients (p = 0.497 and 0.453 respectively). MP- infiltration status did not correlate with CRM implemented resection status in dPDAC patients (p = 0.348). In overall survival analysis, resection status and MP status remained prognostic factors for survival. In follow up analysis. surgical margin clearance in dPDAC patients was associated with a significant improvement in local recurrence rates (5.2% in R0CRM- resected vs. 33.3 in R1/R0CRM + resected, p = 0.002).

CONCLUSION

While resection margin status was not affected by the MP status in dPDAC patients, the high MP infiltration rate, as well as improved survival in MP- dPDAC patients after R0CRM- resection, justify mesopancreatic excision during splenopancreatectomy. Larger scale studies are urgently needed to validate our results and to study the effect on neoadjuvant treatment in dPDAC patients.

Identification of High-Risk Patients for Postoperative Myocardial Injury After CME Using Machine Learning: A 10-Year Multicenter Retrospective Study

Purpose

The occurrence of myocardial injury, a grave complication post complete mesocolic excision (CME), profoundly impacts the immediate and long-term prognosis of patients. The aim of this inquiry was to conceive a machine learning model that can recognize preoperative, intraoperative and postoperative high-risk factors and predict the onset of myocardial injury following CME.

Patients and Methods

This study included 1198 colon cancer patients, 133 of whom experienced myocardial injury after surgery. Thirty-six distinct variables were gathered, encompassing patient demographics, medical history, preoperative examination characteristics, surgery type, and intraoperative details. Four machine learning algorithms, namely, extreme gradient boosting (XGBoost), random forest (RF), multilayer perceptron (MLP), and k-nearest neighbor algorithm (KNN), were employed to fabricate the model, and k-fold cross-validation, ROC curve, calibration curve, decision curve analysis (DCA), and external validation were employed to evaluate it.

Results

Out of the four predictive models employed, the XGBoost algorithm demonstrated the best performance. The ROC curve findings indicated that the XGBoost model exhibited remarkable predictive accuracy, with an area under the curve (AUC) value of 0.997 in the training set and 0.956 in the validation set. For internal validation, the k-fold cross-validation method was utilized, and the XGBoost model was shown to be steady. Furthermore, the calibration curves demonstrated the XGBoost model's high predictive capability. The DCA curve revealed higher benefit rates for patients who underwent interventional treatment under the XGBoost model. The AUC value for the external validation set was 0.74, which indicated that the XGBoost prediction model possessed good extrapolative capacity.

Conclusion

The myocardial injury prediction model for patients undergoing CME that was developed using the XGBoost machine learning algorithm in this study demonstrates both high predictive accuracy and clinical utility.

Comparative effectiveness of pathologic techniques to improve lymph node yield from colorectal cancer specimens. A systematic review and network meta-analysis

BACKGROUND

A number of randomized controlled trials (RCT) have compared different techniques to improve lymph node yield (LNY) in colorectal cancer specimens but data on comparative effectiveness are sparse. Our aim was to compare the relative effectiveness and rank all available techniques.

METHODS

A systematic search of Embase, Cochrane, PubMed and Scopus was performed for randomized trials. Pairwise meta-analysis performed if more than two homogeneous studies were available for each comparison. Network meta-analysis was used to rank and compare all available techniques.

RESULTS

Fifteen studies fulfilled the inclusion criteria. Techniques that were compared included methylene blue (MB), GEWF, Carnoy solution (CS), patent blue (PB), formalin, fat clearing (FC) and their combinations. The overall quality of studies was found to be fair. In pairwise meta-analysis MB had a higher lymph node yield weighted mean difference [WMD] 13.67 [4.83-22.51], P<0.01, lower number of specimens with less than 12 lymph nodes log Odds Ratio= -1.88(-2.8, -0.91), P<0.01 and higher LNY in patients with prior chemoradiotherapy (WMD 9.11 [3.15,15.08], p=0.02) as compared to formalin. Evaluation of the network plot revealed a well-connected network. In network meta-analysis MBFC had a higher LNY with [Mean Difference (MD) 13 and 95% credible interval (CI) (2.09- 23.91)] as compared to formalin. MBFC probability of being the best technique for LNY was 91.4%. In network meta-analysis MB did not have a statistically significant difference when compared to formalin.

CONCLUSIONS

MBFCS seems to be the most effective technique for LNY. Further studies are required to make safe conclusions for outcomes such positive lymph nodes and upstaging.

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.

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.

Minimally invasive complete mesocolic excision for right colon cancer

Complete mesocolic excision (CME) with central vascular ligation (CVL) follows the same principles as the total mesorectal excision (TME) in the rectum of following the embryological planes for right-sided cancers. The number of lymph nodes yielded increased with a resultant improvement in the oncological outcomes and by reducing local recurrence rates. Hohenberger's radical CME and CVL and the East's modified CME with D3 lymphadenectomy, which traditionally followed the embryological plane dissection for most of its intraabdominal cancer resection, have both shown to harvest significantly higher number of lymph nodes leading to a higher overall survival rate than the traditional right hemicolectomies of the West. To achieve the oncologically superior excision of the CME, awareness of the significant vascular anatomical variation will enhance the precision of the oncosurgery as well as minimize the risk of vascular complications. There has been an increasing body of evidence emerging on the safety of minimally invasive surgery (MIS); both its oncological safety as well as complication rates in the hands of expert and trained surgeons. The surgical technique of a CME right hemicolectomy is described step by step to aid standardization. There is mounting evidence that CME + CVL/ D3 improves survival in patients with colon cancer. Whilst the technical aspect of MIS is more challenging than the left, with a standardized technique and systematic teaching method, safety and benefits for patients can be achieved.