Pathological features of lymph nodes around inferior mesenteric artery in rectal cancer: a retrospective study

A nomogram for predicting lymph nodes metastasis at the inferior mesenteric artery in rectal cancer: a retrospective case-control study

According to past and current literature, metastasis of the lymph nodes at the inferior mesenteric artery (IMA-LN), also known as 253LN of colorectal cancer has been seldom investigated. To date, there are still controversies on whether the 253LN need to be routinely cleaned. Using specific criteria, 347 patients who underwent radical resection for rectal cancer between April 2019 and July 2022 were selected for the study. Logistic regression was used to determine the likelihood that a patient may suffer 253LN metastasis, and a nomogram for 253LN metastasis subsequently developed. The c-index and calibration curve were used to evaluate precision and discrimination in the nomogram, and the appropriateness of the final nomogram for the clinical setting determined using decision curve analysis (DCA). 253LN metastases appeared in the pathological specimens of 29 (8.4%) of the selected patients. Logistic regression showed that preoperative parameters including serum carcinoembryonic antigen (CEA) value ( > 5 ng / ml, OR = 2.894, P = 0.023), distance from anal margin (> 9 cm, OR = 2.406, P = 0.045) and degree of differentiation (poor, OR = 9.712, P < 0.001) were significantly associated with 253LN metastasis. A nomogram to predict 253LN metastasis in rectal cancer was developed and showed considerable discrimination and good precision (c-index = 0.750). Furthermore, DCA confirmed that the nomogram has some feasibility for the clinical environment. Clinicopathological and radiological patient data can be pivotal for making surgical decisions relating to 253LN metastasis. A nomogram was developed using this data, providing an objective method that can significantly improve prognoses in colorectal cancer.

Utility of transversus abdominis plane block on patients undergoing transanal total mesorectal excision

Objective

To evaluate the analgesic effect of transversus abdominis plane block (TAPB) on patients undergoing transanal total mesorectal excision (taTME).

Methods

Medical records of patients who were eligible to receive proctectomy surgery in Renji Hospital, Shanghai Jiao Tong University School of Medicine (From January 2019 to December 2021) were retrospectively reviewed. Propensity score matching (PSM) was applied to the included cases. A total of 120 cases were divided into three groups based on the different operation and anesthesia methods used. Group-A (Lap, n=40) included patients that underwent laparoscopic surgery under general anesthesia. Group- B (ta, n=40) included patients who received taTME surgery under general anesthesia. Group-C (ta+TAPB, n=40) included patients who received taTME surgery under general anesthesia combined with TAPB. The dosage of sufentanil, time of postoperative revival and extubation, anal exhaust time and other adverse events were recorded. Pain assessment using the visual analogue scale (VAS) was performed at 12, 24,48 and 72 hours after the operation.

Results

There were no significant differences in the general parameters, operative conditions, and anesthetic administration between the three groups (P>0.05). The dosage of sufentanil was significantly reduced in Group-C, compared with Group-A and Group-B, with no difference between the groups A and B. There was no significant difference between the three groups in postoperative recovery time and extubation time. VAS score was lower in Group-C than Group-A and Group-B. This difference was more obvious in the early postoperative period and gradually diminished with time. VAS score became similar in all three groups 72 hours after the surgery.

Conclusion

Transanal total mesorectal excision was associated with less pain, compared to laparoscopic TME. TAPB with general anesthesia in patients undergoing taTME is safe and effective. It can significantly reduce the use of sufentanil and has optimal analgesic effect.

Development and validation of artificial intelligence models for preoperative prediction of inferior mesenteric artery lymph nodes metastasis in left colon and rectal cancer

BACKGROUND

Dissection of lymph nodes at the roots of the inferior mesenteric artery (IMAN) should be offered only to selected patients at a major risk of developing IMAN involvement. The aim of this study is to present the first artificial intelligence (AI) models to predict IMAN metastasis risk in the left colon and rectal cancer patients.

METHODS

A total of 2891 patients with descending colon including splenic flexure, sigmoid colon and rectal cancer undergoing major primary surgery and IMAN dissection were included as a study cohort, which was then split into a training set (67%) and a testing set (33%). Feature selection was conducted using the least absolute shrinkage and selection operator (LASSO) regression model. Seven AI algorithms, namely Support Vector Machine (SVM), Logistic Regression (LR), Extreme Gradient Boosting (XGB), Light Gradient Boosting (LGB), Decision Tree Classifier (DTC), Random Forest (RF) classifier, and Multilayer Perceptron (MLP), as well as traditional multivariate LR model were employed to construct predictive models. The optimal hyperparameters were determined with 5 fold cross-validation. The predictive performance of models and the expert surgeon was assessed and compared in the testing set independently.

RESULTS

The IMAN involvement incidence was 4.6%. The optimal set of features selected by LASSO included 10 characteristics: neoadjuvant treatment, age, synchronous liver metastasis, synchronous lung metastasis, signet ring adenocarcinoma, neural invasion, lymphovascular invasion, CA199, endoscopic obstruction, T stage evaluated by MRI. The most accurate model derived from MLP showed excellent prediction power with area under the receiver operating characteristic curve (AUROC) of 0.873 and produced 81.0% recognition sensitivity and 82.5% specificity in the testing set independently. In contrast, the judgment of IMAN metastasis by expert surgeon yield rather imprecise and unreliable results with a significantly lower AUROC of 0.509. Additionally, the proposed MLP had the highest net benefits and the largest reduction of unnecessary IMAN dissection without the cost of additional involved IMAN missed.

CONCLUSION

MLP model was able to maintain its prediction accuracy in the testing set better than other models and expert surgeons. Our MLP model could be used to help identify IMA nodal metastasis and to select candidates for individual IMAN dissection.

Brazilian society of surgical oncology: Guidelines for the surgical treatment of mid-low rectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer in North America, Western Europe, and Brazil, and represents an important public health problem. It is estimated that approximately 30% of all the CRC cases correspond to tumors located in the rectum, requiring complex multidisciplinary treatment. In an effort to provide surgeons who treat rectal cancer with the most current information based on the best evidence in the literature, the Brazilian Society of Surgical Oncology (SBCO) has produced the present guidelines for rectal cancer treatment that is focused on the main topics related to daily clinical practice.

OBJECTIVES

The SBCO developed the present guidelines to provide recommendations on the main topics related to the treatment of mid-low rectal cancer based on current scientific evidence.

METHODS

Between May and June 2021, 11 experts in CRC surgery met to develop the guidelines for the treatment of mid-low rectal cancer. A total of 22 relevant topics were disseminated among the participants. The methodological quality of a final list with 221 sources was evaluated, all the evidence was examined and revised, and the treatment guideline was formulated by the 11-expert committee. To reach a final consensus, all the topics were reviewed via a videoconference meeting that was attended by all 11 of the experts.

RESULTS

The prepared guidelines contained 22 topics considered to be highly relevant in the treatment of mid-low rectal cancer, covering subjects related to the tests required for staging, surgical technique-related aspects, recommended measures to reduce surgical complications, neoadjuvant strategies, and nonoperative treatments. In addition, a checklist was proposed to summarize the important information and offer an updated tool to assist surgeons who treat rectal cancer provide the best care to their patients.

CONCLUSION

These guidelines summarize concisely the recommendations based on the most current scientific evidence on the most relevant aspects of the treatment of mid-low rectal cancer and are a practical guide that can help surgeons who treat rectal cancer make the best therapeutic decision.