Impact of pelvic dimensions on anastomotic leak after anterior resection for patients with rectal cancer

Multi-Modal Machine Learning for Evaluating the Predictive Value of Pelvimetric Measurements (Pelvimetry) for Anastomotic Leakage After Restorative Low Anterior Resection

Background/Objectives: Anastomotic leakage (AL) remains a major complication after restorative rectal cancer surgery, with accurate preoperative risk stratification posing a significant challenge. Pelvic measurements derived from magnetic resonance imaging (MRI) have been proposed as potential predictors of AL, but their clinical utility remains uncertain. Methods: This retrospective, multicenter cohort study analyzed rectal cancer patients undergoing restorative surgery between 2013 and 2021. Pelvic dimensions were assessed using MRI-based pelvimetry. Univariate and multivariate regression analyses identified independent risk factors for AL. Subsequently, machine Learning (ML) models-logistic regression, random forest classifier, and XGBoost-were developed to predict AL using preoperative clinical data alone and in combination with pelvimetry. Model performance was evaluated using F1 scores, with the area under the receiver operating characteristic (ROC-AUC) and precision-recall curves (AUC-PR) as primary metrics. Results: Among 487 patients, the overall AL rate was 14%. Multivariate regression analysis identified distance to the anorectal junction, pelvic inlet width, and interspinous distance as independent risk factors for AL (p < 0.05). The logistic regression model incorporating pelvimetry achieved the highest predictive performance, with a mean ROC-AUC of 0.70 ± 0.09 and AUC-PR of 0.32 ± 0.10. Although predictive models that included pelvic measurements demonstrated higher ROC-AUCs compared to those without pelvimetry, the improvement was not statistically significant. Conclusions: Pelvic dimensions, specifically pelvic inlet and interspinous distance, were independently associated with an increased risk of AL. While ML models incorporating pelvimetry showed only moderate predictive performance, these measurements should be considered in developing clinical prediction tools for AL to enhance preoperative risk stratification.

[Anastomotic leaks in colorectal surgery]

A leakage of a colorectal anastomosis represents a severe complication in visceral surgery. An anastomotic insufficiency (AI) is a potentially life-threatening complication for patients that carries a high risk of subsequent complications and long-term stoma care. Numerous factors influence the risk of AI. Knowing and being able to estimate these factors are essential for successful treatment in colorectal surgery as they help determine the surgical strategy. The recognition of an AI can be challenging for practitioners due to the variability in the clinical presentation. If the presence of AI is suspected appropriate diagnostic measures must therefore be taken. If an AI has occurred a colorectal specialist should definitely be involved in the treatment as this can significantly reduce further complications and the rate of permanent stomas.

Prophylactic defunctioning stomas improve clinical outcomes of anastomotic leak following rectal cancer resections: An analysis of the US Rectal Cancer Consortium

PURPOSE

Anastomotic leak (AL) is a complication of low anterior resection (LAR) that results in substantial morbidity. There is immense interest in evaluating immediate postoperative and long-term oncologic outcomes in patients who undergo diverting loop ileostomies (DLI). The purpose of this study is to understand the relationship between fecal diversion, AL, and oncologic outcomes.

METHODS

This is a retrospective multicenter cohort study using patient data obtained from the US Rectal Cancer Consortium database compiled from six academic institutions. The study population included patients with rectal adenocarcinoma undergoing LAR. The primary outcome was the incidence of AL among patients who did or did not receive DLI during LAR. Secondary outcomes included risk factors for AL, receipt of adjuvant therapy, 3-year overall survival, and 3-year recurrence.

RESULTS

Of 815 patients, 38 (4.7%) suffered AL after LAR. Patients with AL were more likely to be male, have unintentional preoperative weight loss, and are less likely to undergo DLI. On multivariable analysis, DLI remained protective against AL (p < 0.001). Diverted patients were less likely to undergo future surgical procedures including additional ostomy creation, completion proctectomy, or pelvic washout for AL. Subgroup analysis of 456 patients with locally advanced disease showed that DLI was correlated with increased receipt of adjuvant therapy for patients with and without AL on univariate analysis (SHR:1.59; [95% CI 1.19-2.14]; p = 0.002), but significance was not met in multivariate models.

CONCLUSION

Lack of DLI and preoperative weight loss was associated with anastomotic leak. Fecal diversion may improve the timely initiation of adjuvant oncologic therapy. The long-term outcomes following routine diverting stomas warrant further study.

What affects the selection of diverting ileostomy in rectal cancer surgery: a single-center retrospective study

BACKGROUND

The selection of diverting ileostomy (DI) is controversial. This study aimed to explore the factors affecting the selection of diverting ileostomy (DI) following laparoscopic low anterior resection for rectal cancer.

METHODS

This retrospective, case-control study included patients who underwent laparoscopic-assisted sphincter-saving surgery for mid-low rectal cancer from January 2019 to June 2021. Univariate and multivariate analyses were performed on the patient's clinicopathological characteristics and pelvic dimensions measured by abdominopelvic electron beam computed tomography.

RESULTS

A total of 382 patients were included in the analysis, of which 182 patients (47.6%) did not undergo DI, and 200 patients (52.4%) underwent DI. The univariate analysis suggested that male sex (p = 0.003), preoperative radiotherapy (p < 0.001), patients with an anastomosis below the levator ani plane (p < 0.001), the intertuberous distance (p < 0.001), the sacrococcygeal distance (p = 0.025), the mid pelvis anteroposterior diameter (p = 0.009), and the interspinous distance (p < 0.001) were associated with performing DI. Multivariate analysis confirmed that preoperative radiotherapy (p = 0.037, odds ratio [OR] = 2.98, 95% confidence interval [CI] = 1.07-8.30), anastomosis below the levator ani plane (p < 0.001, OR = 7.09, 95% CI = 4.13-12.18), and the interspinous distance (p = 0.047, OR = 0.97, 95% CI = 0.93-1.00) were independently associated with performing DI.

CONCLUSION

Pelvic parameters also influence the choice of DI. According to this single-center experience, patients with a shorter interspinous distance, particularly narrow pelvic with an interspinous distance of < 94.8 mm, preoperative radiotherapy, and anastomosis below the levator ani plane, prefer to have a DI and should be adequately prepared by the physician.

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.

Exposure to oestrogen and risk of anastomotic leakage after colorectal cancer surgery - A clue to the different leak rates in men and women

BACKGROUND

Colorectal anastomotic leakage is consistently more common in men, regardless of tumour location. This fact is largely unexplained but might be a consequence of biological differences including hormonal exposure and not only related to anatomy.

METHODS

This was a retrospective, nationwide registry-based observational study of post-menopausal women operated for colorectal cancer with an anastomosis between 2007 and 2016. Hormonal exposure before surgery, as defined by prescribed drugs affecting oestrogen levels, was related to postoperative anastomotic leakage, using mixed-effects logistic regression models with adjustment for confounding. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were derived. In addition, separate estimates according to tumour location were computed, and a sensitivity analysis excluding topical oestrogen hormone exposure was conducted.

RESULTS

Some 16,535 post-menopausal women were included, of which 16.2% were exposed to drugs increasing oestrogen levels before surgery. In this exposed group compared to the unexposed, leak rates were 3.1 and 3.8%, respectively. After adjustment, a reduction of anastomotic leakage in the exposed group was detected (OR: 0.77; 95% CI: 0.59-0.99). This finding was largely attributed to the rectal cancer subgroup (OR: 0.55; 95% CI: 0.36-0.85), while the exclusion of topical oestrogen drugs further reduced the estimates of the main analysis (OR: 0.63; 95% CI: 0.38-1.02).

CONCLUSIONS

Anastomotic leakage rates are lower in women exposed to hormone replacement therapy before surgery for colorectal cancer, which might explain some of the difference in leak rates between men and women, especially regarding rectal cancer.

An MRI-based pelvimetry nomogram for predicting surgical difficulty of transabdominal resection in patients with middle and low rectal cancer

Objective

The current work aimed to develop a nomogram comprised of MRI-based pelvimetry and clinical factors for predicting the difficulty of rectal surgery for middle and low rectal cancer (RC).

Methods

Consecutive mid to low RC cases who underwent transabdominal resection between June 2020 and August 2021 were retrospectively enrolled. Univariable and multivariable logistic regression analyses were carried out for identifying factors (clinical factors and MRI-based pelvimetry parameters) independently associated with the difficulty level of rectal surgery. A nomogram model was established with the selected parameters for predicting the probability of high surgical difficulty. The predictive ability of the nomogram model was assessed by the receiver operating characteristic (ROC) curve and decision curve analysis (DCA).

Results

A total of 122 cases were included. BMI (OR = 1.269, p = 0.006), pelvic inlet (OR = 1.057, p = 0.024) and intertuberous distance (OR = 0.938, p = 0.001) independently predicted surgical difficulty level in multivariate logistic regression analysis. The nomogram model combining these predictors had an area under the ROC curve (AUC) of 0.801 (95% CI: 0.719–0.868) for the prediction of a high level of surgical difficulty. The DCA suggested that using the nomogram to predict surgical difficulty provided a clinical benefit.

Conclusions

The nomogram model is feasible for predicting the difficulty level of rectal surgery, utilizing MRI-based pelvimetry parameters and clinical factors in mid to low RC cases.

Risk Factors and Preventive Measures for Anastomotic Leak in Colorectal Cancer

Anastomotic leak (AL) represents one of the most detrimental complications after colorectal surgery. The patient-related factors and surgery-related factors leading to AL have been identified in previous studies. Through early identification and timely adjustment of risk factors, preventive measures can be taken to reduce potential AL. However, there are still many problems associated with AL. The debate about preventive measures such as preoperative mechanical bowel preparation (MBP), intraoperative drainage, and surgical scope also continues. Recently, the gut microbiota has received more attention due to its important role in various diseases. Although the underlying mechanisms of gut microbiota on AL have not been validated completely, new strategies that manipulate intrinsic mechanisms are expected to prevent and treat AL. Moreover, laboratory examinations for AL prediction and methods for blood perfusion assessment are likely to be promoted in clinical practice. This review outlines possible risk factors for AL and suggests some preventive measures in terms of patient, surgery, and gut microbiota.

Risk Factors for Surgical Treatment of Endometrial Cancer Using Traditional and Laparoscopic Methods

Surgical treatment is the most important part of therapy for endometrial cancer. The aim of the study was to define factors having the most significant impact on surgical treatment of endometrial cancer when using traditional and laparoscopic methods. In the study, we evaluated 75 females who were treated for endometrial cancer via laparoscopic surgery in 2019 and used a historical control of 70 patients treated by laparotomy in 2011. The evaluated risk factors included the method of surgery, type of lymphadenectomy, patient's age, various obesity parameters, histological grading, cancer clinical staging, pelvic dimensions, previous abdominal surgeries, comorbidities, and number of deliveries. The duration of hospitalization, operation time, loss of hemoglobin, and procedure-related complications were used as parameters of perioperative outcomes. Multivariable linear regression analysis confirmed the following factors as being predictors of worse perioperative outcomes: laparotomy, abdominal obesity (waist circumstance and waist-to-hip ratio), range of lymphadenectomy, prior abdominal surgeries, and larger pelvic dimensions. Abdominal obesity is a significant risk factor in the treatment of endometrial cancer. Laparotomy continues to be utilized frequently in the management of endometrial cancer in Poland as well as elsewhere, and adopting a minimally invasive approach is likely to be beneficial for patient outcome.