Learning curve for endoscopic submucosal dissection of gastric submucosal tumors: is it more difficult than it may seem?

Learning curve for endoscopic resection of gastric gastrointestinal stromal tumors: a single-center experience

BACKGROUND

endoscopic resection (ER) is widely used in the treatment of gastric gastrointestinal stromal tumors (gGISTs). However, no studies have previously described the learning curve (LC) for ER of gGISTs. This study aimed to evaluate the LC based on multifarious operative outcomes.

METHODS

one hundred consecutive patients who underwent ER of gGISTs by a single endoscopist from January 2017 to December 2022 were included. Patients were analyzed in groups of ten to minimize demographic differences, and operative time (OT), conversion rate, intraoperative and postoperative complication were assessed to evaluate the LC. Meanwhile, for the OT, the LC was further analyzed using the cumulative sum (CUSUM) method and patients were organized chronologically in three phases.

RESULT

there was a statistically significant decrease in OT, conversion to laparoscopic surgery, and postoperative complication after 30 cases (median 80.0 min vs 56.0 min, p < 0.001; 10.0 % vs 0 %, p = 0.025; 33.3 % vs 10.0 %, p = 0.004), rate of intraoperative complications after 20 cases (15.0 % vs 1.3 %, p = 0.025). CUSUM chart demonstrated that OT increased dramatically before around 30 cases (phase 1) and decreased after 60 cases (phase 3), with a plateau phase in the middle 30 cases (phase 2). Among the three phases, the R0 resection and conversion rate were not significantly different. However, OT, intraoperative and postoperative complications were gradually decreased (p < 0.05).

CONCLUSIONS

the LC of ER of gGISTs is approximately 60 cases. However, about 30 cases were sufficient to acquire skills to reduce complications and conversion rate during the ER procedure.

Assessment of a Real-world Learning Curve for the Endoscopic Resection of Gastric Gastrointestinal Stromal Tumors

BACKGROUND

Endoscopic resection (ER) is a proven treatment for gastric gastrointestinal stromal tumors (gGISTs). We aimed to assess the learning curve (LC) associated with ER for gGISTs and identify determinants.

METHODS

We conducted an analysis of 289 patients who underwent the ER of gGISTs by an experienced endoscopist. To characterize the LC, we employed cumulative sum analysis of the duration of surgery. The participants were divided into an early phase (cases 1-50) and a later phase (case 51-289), which were compared. Furthermore, we identified risk factors for the conversion from endoscopic to laparoscopic resection (LR).

RESULTS

The durations of surgery and hospitalization were shorter, and there were fewer complications and fasting days in the later phase. The conversion rates to LR were 6.0% and 2.5% in the early and later phases, respectively. The tumor diameter (≥3.0 cm) and invasion beyond the muscularis propria were significant risk factors for conversion to LR (odds ratio 17.92, 95% confidence interval 2.66-120.87; and 58.03, 6.40-525.84; respectively).

CONCLUSIONS

The LC for ER of gGISTs lasts for approximately 50 cases. In addition, tumors ≥3.0 cm in diameter and those that invade beyond the muscularis propria are more likely to require conversion to LR.

Development and validation of a preoperative difficulty scoring system for endoscopic resection of gastric gastrointestinal stromal tumor: a multi-center study

BACKGROUND

Endoscopic resection (ER) is a promising technique for resecting gastric gastrointestinal stromal tumors (gGISTs); however, ER is technically challenging. This study aimed to develop and validate a difficulty scoring system (DSS) to determine the difficulty for ER of a gGIST.

METHODS

This retrospective study enrolled 555 patients with gGISTs in multi-centers from December 2010 to December 2022. Data on patients, lesions, and outcomes of ER were collected and analyzed. A difficult case was defined as an operative time ≥ 90 min, or the occurrence of severe intraoperative bleeding, or conversion to laparoscopic resection. The DSS was developed in the training cohort (TC) and validated in the internal validation cohort (IVC) and external validation cohort (EVC).

RESULTS

The difficulty occurred in 97 cases (17.5%). The DSS comprised the following: tumor size ≥ 3.0 cm (3 points) or 2.0-3.0 cm (1 point); location in the upper third of the stomach (2 points); invasion depth beyond the muscularis propria (2 points); lack of experience (1 point). The area under the curve (AUC) of DSS in IVC and EVC was 0.838 and 0.864, respectively, and the negative predictive value (NPV) was 0.923 and 0.972, respectively. The proportions of difficult operation in easy (score 0-3), intermediate (score 4-5), and difficult (score 6-8) categories were 6.5%, 29.4%, and 88.2% in the TC, 7.7%, 45.8%, and 85.7% in the IVC, and 7.0%, 29.4%, and 85.7% in the EVC, respectively.

CONCLUSIONS

We developed and validated a preoperative DSS for ER of gGISTs based on tumor size, location, invasion depth, and endoscopists' experience. This DSS can be used to grade the technical difficulty before surgery.

Automated machine learning to predict the difficulty for endoscopic resection of gastric gastrointestinal stromal tumor

Background

Accurate preoperative assessment of surgical difficulty is crucial to the success of the surgery and patient safety. This study aimed to evaluate the difficulty for endoscopic resection (ER) of gastric gastrointestinal stromal tumors (gGISTs) using multiple machine learning (ML) algorithms.

Methods

From December 2010 to December 2022, 555 patients with gGISTs in multi-centers were retrospectively studied and assigned to a training, validation, and test cohort. A difficult case was defined as meeting one of the following criteria: an operative time ≥ 90 min, severe intraoperative bleeding, or conversion to laparoscopic resection. Five types of algorithms were employed in building models, including traditional logistic regression (LR) and automated machine learning (AutoML) analysis (gradient boost machine (GBM), deep neural net (DL), generalized linear model (GLM), and default random forest (DRF)). We assessed the performance of the models using the areas under the receiver operating characteristic curves (AUC), the calibration curve, and the decision curve analysis (DCA) based on LR, as well as feature importance, SHapley Additive exPlanation (SHAP) Plots and Local Interpretable Model Agnostic Explanation (LIME) based on AutoML.

Results

The GBM model outperformed other models with an AUC of 0.894 in the validation and 0.791 in the test cohorts. Furthermore, the GBM model achieved the highest accuracy among these AutoML models, with 0.935 and 0.911 in the validation and test cohorts, respectively. In addition, it was found that tumor size and endoscopists' experience were the most prominent features that significantly impacted the AutoML model's performance in predicting the difficulty for ER of gGISTs.

Conclusion

The AutoML model based on the GBM algorithm can accurately predict the difficulty for ER of gGISTs before surgery.

Quantifying early gastric cancer in Australia: What is the opportunity for gastric endoscopic submucosal dissection?

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) is the recommended treatment for early gastric cancer (EGC). However, there are challenges in attaining expertise in ESD in countries where the incidence of gastric cancer and proportion diagnosed at an early stage of disease are relatively low. This study aims to establish the proportion of gastric cancer meeting histological criteria for EGC, which may be suitable for ESD, in a Western population.

METHODS

Gastric cancers reported to the Victorian Cancer Registry between January 2011 and December 2016 were analyzed. EGC was defined as tumor confined to mucosa (T1a) or submucosa (T1b). Histology reports were analyzed using Japanese and European guidelines to identify potential ESD candidates. Criteria for extended ESD were based on grade of differentiation, tumor depth, lymphovascular and perineural invasion, and ulceration.

RESULTS

Twenty percent of 1217 gastric cancers was EGC (237 cases), with detailed histopathology reports suitable for evaluating ESD criteria recorded in 182 cases. Standard and extended ESD criteria were met in 46% (84/182) and 75% (132/182), respectively. Actual treatment of the 237 EGC was endoscopic in 14% (n = 33) and surgery in 86% (n = 204). Endoscopically treated EGCs were more likely to be stage T1a and located in the proximal stomach.

CONCLUSIONS

EGCs represented 20% of reported gastric adenocarcinomas with the majority fulfilling criteria for ESD. ESD should be considered in the management algorithm and discussed at tumor board meetings involving interventional endoscopists. To increase utilization of ESD, systems need to be implemented to improve training, accreditation, and access to ESD.

Usefulness of tumor traction with a snare and endoclips in gastric submucosal tumor resection: a propensity-score-matching analysis

Background

Endoscopic resection, including endoscopic submucosal dissection (ESD) and endoscopic full-thickness resection (EFR), was used to resect small gastric submucosal tumors (SMTs). Our team explored a method of tumor traction using a snare combined with endoclips to assist in the resection of SMTs. This study aims to explore the safety and effectiveness of the method.

Methods

This research performed a propensity-score-matching (PSM) analysis to compare ESD/EFR assisted by a snare combined with endoclips (ESD/EFR with snare traction) with conventional ESD/EFR for the resection of gastric SMTs. Comparisons were made between the two groups, including operative time, en bloc resection rate, perioperative complications, and operation-related costs.

Results

A total of 253 patients with gastric SMTs resected between January 2012 and March 2019 were included in this study. PSM yielded 51 matched pairs. No significant differences were identified between the two groups in perioperative complications or the costs of disposable endoscopic surgical accessories. However, the ESD/EFR-with-snare-traction group had a shorter median operative time (39 vs 60 min, P = 0.005) and lower rate of en bloc resection (88.2% vs 100%, P = 0.027).

Conclusions

ESD/EFR with snare traction demonstrated a higher efficiency and en bloc resection rate for gastric SMTs, with no increases in perioperative complications and the costs of endoscopic surgical accessories. Therefore, the method seems an appropriate choice for the resection of gastric SMTs.

Splash M-knife versus Flush Knife BT in the technical outcomes of endoscopic submucosal dissection for early gastric cancer: a propensity score matching analysis

BACKGROUND

Endoscopic submucosal dissection (ESD) is a standard treatment for early gastric cancer. A new multi-functional ESD device was developed to achieve complete ESD with a single device. A metal plate attached to its distal sheath achieves better hemostasis during the procedure than the other needle-knife device, Flush Knife BT®, that has been conventionally used. The aim of this study was to compare the technical outcomes of ESD for early gastric cancer using the Splash M-Knife® with those using the Flush Knife BT.

METHODS

We conducted a retrospective review of the case records of 149 patients with early gastric cancer treated with ESD using the needle-type ESD knives between January 2012 and August 2016 at Kitakyushu Municipal Medical Center. Lesions treated with ESD using the Splash M-knife (ESD-M) and the Flush Knife BT (ESD-F) were compared. Multivariate analyses and propensity score matching were used to compensate for the differences in age, gender, underlying disease, antithrombotic drug use, lesion location, lesion position, macroscopic type, tumor size, presence of ulceration, operator level and types of electrosurgical unit used. The primary endpoint was the requirement to use hemostatic forceps in the two groups. The secondary endpoints of procedure time, en bloc and complete resection rates, and adverse events rates were evaluated for the two groups.

RESULTS

There were 73 patients in the ESD-M group, and 76 patients in the ESD-F group. Propensity score matching analysis created 45 matched pairs. Adjusted comparisons between the two groups showed a significantly lower usage rate of hemostatic forceps in the ESD-M group than in the ESD-F group (6.7% vs 84.4%, p < 0.001). Treatment outcomes showed an en bloc resection rate of 100% in both groups; complete resection rate of 95.6% vs 100%, p = 0.49; median procedure time of 74.0 min vs 71.0 min, p = 0.90; post-procedure bleeding of 2.2% vs 2.2%, p = 1, in the ESD-M and ESD-F groups, respectively. There were no perforations in either group.

CONCLUSIONS

ESD-M appeared to reduce the usage of hemostatic forceps during ESD for early gastric cancer without increasing the adverse effects. Thus, it may contribute to a reduction in the total ESD cost.