A Clinical Parameters-Based Model Predicts Anastomotic Leakage After a Laparoscopic Total Mesorectal Excision: A Large Study With Data From China

Machine learning-based preoperative analytics for the prediction of anastomotic leakage in colorectal surgery: a swiss pilot study

BACKGROUND

Anastomotic leakage (AL), a severe complication following colorectal surgery, arises from defects at the anastomosis site. This study evaluates the feasibility of predicting AL using machine learning (ML) algorithms based on preoperative data.

METHODS

We retrospectively analyzed data including 21 predictors from patients undergoing colorectal surgery with bowel anastomosis at four Swiss hospitals. Several ML algorithms were applied for binary classification into AL or non-AL groups, utilizing a five-fold cross-validation strategy with a 90% training and 10% validation split. Additionally, a holdout test set from an external hospital was employed to assess the models' robustness in external validation.

RESULTS

Among 1244 patients, 112 (9.0%) suffered from AL. The Random Forest model showed an AUC-ROC of 0.78 (SD: ± 0.01) on the internal test set, which significantly decreased to 0.60 (SD: ± 0.05) on the external holdout test set comprising 198 patients, including 7 (3.5%) with AL. Conversely, the Logistic Regression model demonstrated more consistent AUC-ROC values of 0.69 (SD: ± 0.01) on the internal set and 0.61 (SD: ± 0.05) on the external set. Accuracy measures for Random Forest were 0.82 (SD: ± 0.04) internally and 0.87 (SD: ± 0.08) externally, while Logistic Regression achieved accuracies of 0.81 (SD: ± 0.10) and 0.88 (SD: ± 0.15). F1 Scores for Random Forest moved from 0.58 (SD: ± 0.03) internally to 0.51 (SD: ± 0.03) externally, with Logistic Regression maintaining more stable scores of 0.53 (SD: ± 0.04) and 0.51 (SD: ± 0.02).

CONCLUSION

In this pilot study, we evaluated ML-based prediction models for AL post-colorectal surgery and identified ten patient-related risk factors associated with AL. Highlighting the need for multicenter data, external validation, and larger sample sizes, our findings emphasize the potential of ML in enhancing surgical outcomes and inform future development of a web-based application for broader clinical use.

Systematic review of preoperative and intraoperative colorectal Anastomotic Leak Prediction Scores (ALPS)

OBJECTIVE

To systematically review preoperative and intraoperative Anastomotic Leak Prediction Scores (ALPS) and validation studies to evaluate performance and utility in surgical decision-making. Anastomotic leak (AL) is the most feared complication of colorectal surgery. Individualised leak risk could guide anastomosis and/or diverting stoma.

METHODS

Systematic search of Ovid MEDLINE and Embase databases, 30 October 2020, identified existing ALPS and validation studies. All records including >1 risk factor, used to develop new, or to validate existing models for preoperative or intraoperative use to predict colorectal AL, were selected. Data extraction followed CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies guidelines. Models were assessed for applicability for surgical decision-making and risk of bias using Prediction model Risk Of Bias ASsessment Tool.

RESULTS

34 studies were identified containing 31 individual ALPS (12 colonic/colorectal, 19 rectal) and 6 papers with validation studies only. Development dataset patient populations were heterogeneous in terms of numbers, indication for surgery, urgency and stoma inclusion. Heterogeneity precluded meta-analysis. Definitions and timeframe for AL were available in only 22 and 11 ALPS, respectively. 26/31 studies used some form of multivariable logistic regression in their modelling. Models included 3-33 individual predictors. 27/31 studies reported model discrimination performance but just 18/31 reported calibration. 15/31 ALPS were reported with external validation, 9/31 with internal validation alone and 4 published without any validation. 27/31 ALPS and every validation study were scored high risk of bias in model analysis.

CONCLUSIONS

Poor reporting practices and methodological shortcomings limit wider adoption of published ALPS. Several models appear to perform well in discriminating patients at highest AL risk but all raise concerns over risk of bias, and nearly all over wider applicability. Large-scale, precisely reported external validation studies are required.

PROSPERO REGISTRATION NUMBER

CRD42020164804.

Predictive Factors for Anastomotic Leakage Following Colorectal Cancer Surgery: Where Are We and Where Are We Going?

Anastomotic leakage (AL) remains one of the most severe complications following colorectal cancer (CRC) surgery. Indeed, leaks that may occur after any type of intestinal anastomosis are commonly associated with a higher reoperation rate and an increased risk of postoperative morbidity and mortality. At first, our review aims to identify specific preoperative, intraoperative and perioperative factors that eventually lead to the development of anastomotic dehiscence based on the current literature. We will also investigate the role of several biomarkers in predicting the presence of ALs following colorectal surgery. Despite significant improvements in perioperative care, advances in surgical techniques, and a high index of suspicion of this complication, the incidence of AL remained stable during the last decades. Thus, gaining a better knowledge of the risk factors that influence the AL rates may help identify high-risk surgical patients requiring more intensive perioperative surveillance. Furthermore, prompt diagnosis of this severe complication may help improve patient survival. To date, several studies have identified predictive biomarkers of ALs, which are most commonly associated with the inflammatory response to colorectal surgery. Interestingly, early diagnosis and evaluation of the severity of this complication may offer a significant opportunity to guide clinical judgement and decision-making.

Operative blood loss adversely affects short and long-term outcomes after colorectal cancer surgery: results of a systematic review and meta-analysis

BACKGROUND

The aim of this meta-analysis was to assess the impact of operative blood loss on short and long-term outcomes following colorectal cancer surgery.

METHODS

A systematic literature review and meta-analysis were performed, from inception to the 10th of August 2020. A comprehensive literature search was performed on the 10th of August 2020 of PubMed MEDLINE, Embase, Science Citation Index Expanded, and Cochrane Central Register of Controlled Trials. Only studies reporting on operative blood loss and postoperative short term or long-term outcomes in colorectal cancer surgery were considered for inclusion.

RESULTS

Forty-three studies were included, reporting on 59,813 patients. Increased operative blood loss was associated with higher morbidity, for blood loss greater than 150-350 ml (odds ratio [OR] 2.09, p < 0.001) and > 500 ml (OR 2.29, p = 0.007). Anastomotic leak occurred more frequently for blood loss above a range of 50-100 ml (OR 1.14, p = 0.007), 250-300 ml (OR 2.06, p < 0.001), and 400-500 ml (OR 3.15, p < 0.001). Postoperative ileus rate was higher for blood loss > 100-200 ml (OR 1.90, p = 0.02). Surgical site infections were more frequent above 200-500 ml (OR 1.96, p = 0.04). Hospital stay was increased for blood loss > 150-200 ml (OR 1.63, p = 0.04). Operative blood loss was significantly higher in patients that suffered morbidity (mean difference [MD] 133.16 ml, p < 0.001) or anastomotic leak (MD 69.56 ml, p = 0.02). In the long term, increased operative blood loss was associated with worse overall survival above a range of 200-500 ml (hazard ratio [HR] 1.15, p < 0.001), and worse recurrence-free survival above 200-400 ml (HR 1.33, p = 0.01). Increased blood loss was associated with small bowel obstruction caused by colorectal cancer recurrence for blood loss higher than 400 ml (HR 1.97, p = 0.03) and 800 ml (HR 3.78, p = 0.02).

CONCLUSIONS

Increased operative blood loss may adversely impact short term and long-term postoperative outcomes. Measures should be taken to minimize operative blood loss during colorectal cancer surgery. Due to the uncertainty of evidence identified, further research, with standardised methodology, is required on this important subject.

Artificial intelligence assists surgeons' decision-making of temporary ileostomy in patients with rectal cancer who have received anterior resection

BACKGROUND

Due to the difficult evaluation of the risk of anastomotic leakage (AL) after rectal cancer resection, the decision to perform a temporary ileostomy is not easily distinguishable. The aim of the present study was to develop an artificial intelligence (AI) model for identifying the risk of AL to assist surgeons in the selective implementation of a temporary ileostomy.

MATERIALS AND METHODS

The data from 2240 patients with rectal cancer who received anterior resection were collected, and these patients were divided into one training and two test cohorts. Five AI algorithms, such as support vector machine (SVM), logistic regression (LR), Naive Bayes (NB), stochastic gradient descent (SGD) and random forest (RF) were employed to develop predictive models using clinical variables and were assessed using the two test cohorts.

RESULTS

The SVM model indicated good discernment of AL, and might have increased the implementation of temporary ileostomy in patients with AL in the training cohort (p < 0.001). Following the assessment of the two test cohorts, the SVM model could identify AL in a favorable manner, which performed with positive predictive values of 0.150 (0.091-0.234) and 0.151 (0.091-0.237), and negative predictive values of 0.977 (0.958-0.988) and 0.986 (0.969-0.994), respectively. It is important to note that the implementation of temporary ileostomy in patients without AL would have been significantly reduced (p < 0.001) and which would have been significantly increased in patients with AL (p < 0.05).

CONCLUSION

The model (https://alrisk.21cloudbox.com/) indicated good discernment of AL, which may be used to assist the surgeon's decision-making of performing temporary ileostomy.

Association between circular stapler size and anastomotic leakage after laparoscopic low anterior resection for rectal cancer

Background

Anastomotic leakage (AL) is one of the most severe and frequent complications occurring after laparoscopic low anterior resection (LAR) for rectal cancer. This study aimed to examine the association between circular stapler size and AL after laparoscopic LAR.

Methods

This retrospective single-institution study involved 181 patients with rectal cancer who underwent laparoscopic LAR performed by a single surgical team between July 2016 and June 2021. The characteristics of the patients were analyzed. Risk factors for AL were identified via univariate and multivariate analyses. Additionally, a further propensity score matching (PSM) analysis was performed to reduce the selection bias.

Results

Among the 181 patients who underwent laparoscopic LAR for rectal cancer, 17 (9.4%) developed clinical AL. In the univariate and multivariate analyses, male sex, incomplete intestinal obstruction, and the usage of a 32-mm stapler during the surgery were independent risk factors for the occurrence of AL. Furthermore, the PSM analysis confirmed that the incidence of AL with a 32-mm stapler was higher than that with a 29-mm stapler after laparoscopic low anterior resection. However, there was no difference in the incidence of anastomotic bleeding and stenosis.

Conclusion

Choosing a smaller-diameter circular stapler may reduce the incidence of AL after laparoscopic LARfor rectal cancer without increasing the incidence of anastomotic stenosis.

A systematic review of the literature assessing operative blood loss and postoperative outcomes after colorectal surgery

PURPOSE

There is no consensus in the literature regarding the association between operative blood loss and postoperative outcomes in colorectal surgery, despite evidence suggesting a link. Therefore, this systematic review assesses the association between operative blood loss, perioperative and long-term outcomes after colorectal surgery.

METHODS

A literature search of MEDLINE, EMBASE, Science Citation Index Expanded and Cochrane was performed to identify studies reporting on operative blood loss in colorectal surgery.

RESULTS

The review included forty-nine studies reporting on 61,312 participants, with a mean age ranging from 53.4 to 78.1 years. The included studies demonstrated that major operative blood loss was found to be a risk factor for mortality, anastomotic leak, presacral abscess, and postoperative ileus, leading to an increased duration of hospital stay. In the long term, the studies suggest that significant blood loss was an independent risk factor for future small bowel obstruction due to colorectal cancer recurrence and adhesions. Studies found that survival was significantly reduced, whilst the risk of colorectal cancer recurrence was increased. Reoperation and cancer-specific survival were not associated with major blood loss.

CONCLUSION

The results of this systematic review suggest that major operative blood loss increases the risk of perioperative adverse events and has short and long-term repercussions on postoperative outcomes. Laparoscopic and robotic surgery, vessel ligation technology and anaesthetic considerations are essential for reducing blood loss and improving outcomes. This review highlights the need for further high quality, prospective, multicentre trials with a greater number of participants, and accurate and standardised methods of measuring operative blood loss.

Transanal Drainage Tube Use for Preventing Anastomotic Leakage After Laparoscopic Low Anterior Resection in Patients With Rectal Cancer: A Randomized Clinical Trial

Importance

Preventing anastomotic leakage (AL) is crucial for colorectal surgery. Some studies have suggested a positive role of transanal drainage tubes (TDTs) in AL prevention after low anterior resection, but this finding is controversial.

Objective

To assess the effect of TDTs in AL prevention after laparoscopic low anterior resection for rectal cancer.

Design, Setting, and Participants

This multicenter randomized clinical trial with parallel groups (TDT vs non-TDT) was performed from February 26, 2016, to September 30, 2020. Participants included patients from 7 different hospitals in China who were undergoing laparoscopic low anterior resection with the double-stapling technique for mid-low rectal cancer; 576 patients were initially enrolled in this study, and 16 were later excluded. Ultimately, 560 patients were randomly divided between the TDT and non-TDT groups.

Interventions

A silicone tube was inserted through the anus, and the tip of the tube was placed approximately 5 cm above the anastomosis under laparoscopy at the conclusion of surgery. The tube was fixed with a skin suture and connected to a drainage bag. The TDT was scheduled for removal 3 to 7 days after surgery.

Main Outcomes and Measures

The primary end point was the postoperative AL rate within 30 days.

Results

In total, 576 patients were initially enrolled in this study; 16 of these patients were excluded. Ultimately, 560 patients were randomly divided between the TDT group (n = 280; median age, 61.5 years [IQR, 54.0-68.8 years]; 177 men [63.2%]) and the non-TDT group (n = 280; median age, 62.0 years [IQR, 52.0-69.0 years]; 169 men [60.4%]). Intention-to-treat analysis showed no significant difference between the TDT and non-TDT groups in AL rates (18 [6.4%] vs 19 [6.8%]; relative risk, 0.947; 95% CI, 0.508-1.766; P = .87) or AL grades (grade B, 14 [5.0%] and grade C, 4 [1.4%] vs grade B, 11 [3.9%] and grade C, 8 [2.9%]; P = .43). In the stratified analysis based on diverting stomas, there was no significant difference in the AL rate between the groups, regardless of whether a diverting stoma was present (without stoma, 12 [5.8%] vs 15 [7.9%], P = .41; and with stoma, 6 [8.3%] vs 4 [4.5%], P = .50). Anal pain was the most common complaint from patients in the TDT group (130 of 280, 46.4%). Accidental early TDT removal occurred in 20 patients (7.1%), and no bleeding or iatrogenic colonic perforations were detected.

Conclusions and Relevance

The results from this randomized clinical trial indicated that TDTs may not confer any benefit for AL prevention in patients who undergo laparoscopic low anterior resection for mid-low rectal cancer without preoperative radiotherapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02686567.

Comparison of the efficacy of growth factor collagen and antibiotic collagen on colon anastomosis in experimental animals with peritonitis

INTRODUCTION

In spite of advances in surgical techniques, the significance of anastomosis leak continues in colorectal surgery. There is no ideal method in spite of all studies and technical advances in this field. Our aim of this study was to use fibroblast growth factor collagen (FGF-C) and antibiotic collagen (AB-C) to increase the rate of anastomosis healing in experimental animals with peritonitis.

METHODS

This animal experimental study received ethics committee approval. The animals were divided into three groups of seven animals each; the first group was control, the second group was the fibroblast growth factor collagen group, and the third group was the antibiotic collagen group. Under anesthesia, more than 50% of the colonic lumen was opened 4-5 cm distal to the ileocecal junction to create a defect. Twenty-four hours later, primary anastomosis was performed. The second group had the anastomosis line covered with a cover containing FGF-C. The third group had the anastomosis line covered by material containing AB-C. The experiment was concluded on the postoperative 7th day, and the anastomosis burst pressure, tissue hydroxyproline level, and histopathological assessment were performed.

RESULTS

Though the burst pressure was higher in the experimental groups, it was not statistically significant. In the second and third groups, vascular proliferation and fibroblastic activity appeared to be better than in the control group. Hydroxyproline values were statistically significant in the experimental groups compared to the control group.

CONCLUSION

FGF-C and AB-C may have potential utility in anastomosis healing, especially in those susceptible to infection due to anastomosis leak.

Colorectal anastomosis dehiscence: a call for more detailed morphological classification

Introduction

A proactive approach is recommended in colorectal anastomosis leak treatment, and early diagnosis is very important. Early postoperative endoscopy would allow rapid diagnosis of anastomotic pathologies and consequent prompt intervention according to anastomotic disruption morphology.

Aim

To evaluate the effectiveness of close endoscopic follow-up of all patients (including asymptomatic ones) in improving diagnosis of acute leak (AL) and reducing its complications.

Material and methods

This study included 124 patients who had undergone rectum resection for rectal cancer with stapled anastomosis. Endoscopy was performed between the 7^th and 10^th postoperative day and 1 month postoperatively. For defect morphology assessment, a classification system was created based on four levels of severity. Photographic findings were evaluated by an independent, experienced gastroenterologist.

Results

Postoperative endoscopy revealed 28 (22.6%) patients with acute leakage. Initial endoscopy confirmed AL in 18 patients. Six (31.6%) patients were asymptomatic and 13 (68.4%) were symptomatic. The second endoscopy revealed another 9 (32.1%) leaks (4 (44.5%) asymptomatic and 5 (55.5%) symptomatic). Sixteen (57.1%) patients had grade A leakages, 7 (25.0%) had grade B leakages, and 5 (17.9%) had grade C leakages. Furthermore, 22 of 27 (81%) defects were located posterior and posterior-laterally. Fifteen (55.5%) defects were smaller than 1/3 the circumference, 7 (25.9%) affected 1/3–1/2 of the circumference, and 5 (18.5%) affected more than 1/2 of the circumference.

Conclusions

Incorporation of early endoscopy in postoperative management allows rapid diagnosis of AL and allows faster intervention, even in leaks that are clinically silent.

Risk prediction models for postoperative outcomes of colorectal cancer surgery in the older population - a systematic review

BACKGROUND

An increasing number of patients with Colorectal Cancer (CRC) is 65 years or older. We aimed to systematically review existing clinical prediction models for postoperative outcomes of CRC surgery, study their performance in older patients and assess their potential for preoperative decision making.

METHODS

A systematic search in Pubmed and Embase for original studies of clinical prediction models for outcomes of CRC surgery. Bias and relevance for preoperative decision making with older patients were assessed using the CHARMS guidelines.

RESULTS

26 prediction models from 25 publications were included. The average age of included patients ranged from 61 to 76. Two models were exclusively developed for 65 and older. Common outcomes were mortality (n = 10), anastomotic leakage (n = 7) and surgical site infections (n = 3). No prediction models for quality of life or physical functioning were identified. Age, gender and ASA score were common predictors; 12 studies included intraoperative predictors. For the majority of the models, bias for model development and performance was considered moderate to high.

CONCLUSIONS

Prediction models are available that address mortality and surgical complications after CRC surgery. Most models suffer from methodological limitations, and their performance for older patients is uncertain. Models that contain intraoperative predictors are of limited use for preoperative decision making. Future research should address the predictive value of geriatric characteristics to improve the performance of prediction models for older patients.

High versus low ligation of inferior mesenteric artery during laparoscopic radical resection of rectal cancer: A retrospective cohort study

Laparoscopic radical resection is standard treatment for resectable rectal cancer. However, whether high or low inferior mesenteric artery (IMA) ligation should be performed remains controversial. This retrospective cohort study compared the advantages and disadvantages of low vs high IMA ligation in patients undergoing laparoscopic total mesorectal excision for rectal cancer.Rectal cancer patients (n = 322) undergoing total mesorectal excision at our institution in 2010 to 17 were enrolled; 174 underwent high IMA ligation group and 148 low IMA ligation (LIMAL group). Baseline data on patients, operative indices, economic indices, pathology findings, perioperative complications, and survival in the 2 groups were analyzed retrospectively.The low IMA ligation group had significantly higher anus retention ratio (P = .022), shorter hospital stay (P = .025), lower medical expenses (P = .032), fewer cases of anastomotic leakage (P = .023) and anastomotic stricture (P < .001), and lower incidence of postoperative genitourinary dysfunction (P = .003). Cox regression analysis indicated that local recurrence, distant metastasis, tumor differentiation, and tumor-node-metastasis stage were independently associated with survival.Low ligation of the IMA during laparoscopic radical resection of rectal cancer appears to be associated with a lower risks for anastomotic leakage, anastomotic stricture, and genitourinary dysfunction, a shorter hospital stay, and lower costs. In contrast, the rate of lymph node harvest, tumor recurrence rate, metastasis, or mortality was not found to be related with the level of IMA ligation.

Drain fluid's pH predicts anastomotic leak in colorectal surgery: results of a prospective analysis of 173 patients

BACKGROUND

The early risk assessment of anastomotic leak (AL) after colorectal surgery is crucial. Several markers have been proposed, including peritoneal fluid's pH. Aim of the present study is to evaluate the role of drain fluid pH as predictor of AL.

METHODS

All patients undergoing colorectal surgery from January 2015 to December 2017 were considered eligible. Hartmann procedures, procedures including temporary ileostomy and emergency surgery were excluded. Drain fluid was submitted for pH and chemical-physical assessment on postoperative day 1 (POD1) and postoperative day 3 (POD3).

RESULTS

Out of 173 patients, those who developed AL showed a lower drain fluid's pH on POD1 and on POD3 compared to patients who did not (P<0.05). The plotted ROC curves identified 7.53 as pH cut-off on POD1 (AUC 0.80) and 7.21 on POD3 (AUC 0.86). With both the cut-offs, pH was an independent predictor of AL at multivariable analysis (P<0.001). pH<7.53 on POD1 and pH<7.21 on POD3 showed 93.75% sensitivity and 97% specificity respectively.

CONCLUSIONS

Drain fluid's pH on POD1 is useful to select patients who will not develop AL while on POD3 it might identify those requiring a more careful management.

MRI-based score to predict surgical difficulty in patients with rectal cancer

BACKGROUND

Rectal cancer surgery is technically challenging and depends on many factors. This study evaluated the ability of clinical and anatomical factors to predict surgical difficulty in total mesorectal excision.

METHODS

Consecutive patients who underwent total mesorectal excision for locally advanced rectal cancer in a laparoscopic, robotic or open procedure after neoadjuvant treatment, between 2005 and 2014, were included in this retrospective study. Preoperative clinical and MRI data were studied to develop a surgical difficulty grade.

RESULTS

In total, 164 patients with a median age of 61 (range 26-86) years were considered to be at low risk (143, 87·2 per cent) or high risk (21, 12·8 per cent) of surgical difficulty. In multivariable analysis, BMI at least 30 kg/m² (P = 0·021), coloanal anastomosis (versus colorectal) (P = 0·034), intertuberous distance less than 10·1 cm (P = 0·041) and mesorectal fat area exceeding 20·7 cm² (P = 0·051) were associated with greater surgical difficulty. A four-item score (ranging from 0 to 4), with each item (BMI, type of surgery, intertuberous distance and mesorectal fat area) scored 0 (absence) or 1 (presence), is proposed. Patients can be considered at high risk of a difficult or challenging operation if they have a score of 3 or more.

CONCLUSION

This simple morphometric score may assist surgical decision-making and comparative study by defining operative difficulty before surgery.