Recent approach for preventing complications in upper gastrointestinal endoscopic submucosal dissection

Which of Vonoprazan Alone or Intravenous Proton Pump Inhibitor Followed by Vonoprazan Is Optimal for Reducing Delayed Bleeding in Gastric Endoscopic Submucosal Dissection?

INTRODUCTION

In gastric endoscopic submucosal dissection (ESD), both vonoprazan alone and intravenous proton pump inhibitor (PPI) followed by vonoprazan have lower delayed bleeding risk than PPI alone. This study aimed to clarify an optimal acid-suppressive method in gastric ESD.

METHODS

This population-based cohort study included patients who underwent gastric ESD on only vonoprazan (vonoprazan alone group) or intravenous PPI followed by vonoprazan (intravenous PPI group) using the Diagnosis Procedure Combination database in Japan between 2014 and 2021. The primary outcome was delayed bleeding. To balance the two comparison groups, propensity score matching (PSM), based on 18 variables, was performed; subsequently, to compare the bleeding outcome, logistic regression analysis was performed.

RESULTS

Of 63,952 patients, 24,710 pairs were compared following PSM. The delayed bleeding risk in the vonoprazan alone group was similar to that in the intravenous PPI group (odds ratio [OR], 1.00; 95% confidence interval, 0.93-1.08; delayed bleeding rate, 5.9% vs. 5.9%). The results were consistent in some sensitivity and subgroup analyses; however, the result was modified by the status of antithrombotic agents (p for interaction = 0.029). In additional analyses, in patients with antithrombotic agent, the vonoprazan alone group had a higher delayed bleeding risk than the intravenous PPI group (OR, 1.15).

CONCLUSION

Both vonoprazan alone and intravenous PPI followed by vonoprazan might be acceptable in gastric ESD when antithrombotic agents were not administered, whereas intravenous PPI followed by vonoprazan might be favorable in patients with antithrombotic agents.

Effects of a training system that tracks the operator's gaze pattern during endoscopic submucosal dissection on hemostasis

BACKGROUND

The early acquisition of skills required to perform hemostasis during endoscopy may be hindered by the lack of tools that allow assessments of the operator's viewpoint. Understanding the operator's viewpoint may facilitate the skills.

AIM

To evaluate the effects of a training system using operator gaze patterns during gastric endoscopic submucosal dissection (ESD) on hemostasis.

METHODS

An eye-tracking system was developed to record the operator's viewpoints during gastric ESD, displaying the viewpoint as a circle. In phase 1, videos of three trainees' viewpoints were recorded. After reviewing these, trainees were recorded again in phase 2. The videos from both phases were retrospectively reviewed, and short clips were created to evaluate the hemostasis skills. Outcome measures included the time to recognize the bleeding point, the time to complete hemostasis, and the number of coagulation attempts.

RESULTS

Eight cases treated with ESD were reviewed, and 10 video clips of hemostasis were created. The time required to recognize the bleeding point during phase 2 was significantly shorter than that during phase 1 (8.3 ± 4.1 seconds vs 23.1 ± 19.2 seconds; P = 0.049). The time required to complete hemostasis during phase 1 and that during phase 2 were not significantly different (15.4 ± 6.8 seconds vs 31.9 ± 21.7 seconds; P = 0.056). Significantly fewer coagulation attempts were performed during phase 2 (1.8 ± 0.7 vs 3.2 ± 1.0; P = 0.004).

CONCLUSION

Short-term training did not reduce hemostasis completion time but significantly improved bleeding point recognition and reduced coagulation attempts. Learning from the operator's viewpoint can facilitate acquiring hemostasis skills during ESD.

Tunneled or pocket creation method versus conventional endoscopic submucosal dissection for gastric lesions: a systematic review and meta-analysis

BACKGROUND AND AIMS

Tunneled endoscopic submucosal dissection (T-ESD) and pocket creation-method ESD (PCM-ESD) are considered to have technical advantages over conventional ESD (C-ESD). However, data comparing these techniques for ESD of gastric lesions are limited.

METHODS

PubMed and Cochrane databases were reviewed for relevant studies from their inceptions to October 31, 2023. Studies comparing T-ESD or PCM-ESD (T/PCM-ESD) with C-ESD for gastric lesions were included. The primary outcomes were dissection speed and en-bloc resection. Secondary outcomes were R0 resection, recurrence, perforation, and post-ESD bleeding. A random effects meta-analysis was conducted.

RESULTS

Eight observational studies (359 patients with T/PCM-ESD, 670 patients with C-ESD) were included. T/PCM-ESD was associated with a significantly faster dissection speed (mean difference, 4.42 mm2/min; 95% confidence interval [CI], 2.05-6.79; I2 = 79%). There were no significant differences between the groups in terms of en-bloc resection (risk ratio [RR], 1.01; 95% CI, 1.00-1.03; I2 = 0%), R0 resection (RR, 1.03; 95% CI, 0.99-1.07; I2 = 0%), and recurrence (RR, 0.73; 95% CI, 0.14-3.84; I2 = 0%). Although T/PCM-ESD was associated with a significantly lower risk of perforation (RR, 0.21; 95% CI, 0.06-0.80; I2 = 0%), post-ESD bleeding rates were not significantly different.

CONCLUSIONS

T/PCM-ESD facilitates faster and safer gastric ESD than C-ESD, with similar en-bloc resection, R0 resection, and recurrence rates. A future randomized controlled control trial is required.

Optimal direct oral anticoagulant for upper gastrointestinal endoscopic submucosal dissection

BACKGROUND

The patients taking direct oral anticoagulants (DOACs) are at high risk for developing ischemic stroke and delayed bleeding in upper gastrointestinal endoscopic submucosal dissection (ESD). We aimed to identify the optimal DOAC based on both adverse events in upper gastrointestinal ESD.

METHODS

A retrospective population-based cohort study was conducted using the Diagnosis Procedure Combination database in Japan. We included patients on a DOAC undergoing upper gastrointestinal ESD between 2012 and 2021. The primary outcomes were ischemic stroke occurring after upper gastrointestinal ESD and delayed bleeding in gastroduodenal and esophageal ESD. Inverse probability weightings were applied to balance the four DOAC groups (dabigatran, rivaroxaban, apixaban, and edoxaban), and logistic regression analyses were performed to compare the outcomes.

RESULTS

We analyzed 9729 patients on a DOAC undergoing upper gastrointestinal ESD. Ischemic stroke developed after upper gastrointestinal ESD in 1.4%, 0.7%, 0.6%, and 0.8% of patients taking dabigatran, rivaroxaban, apixaban, and edoxaban, respectively, after weighting. Rivaroxaban and apixaban showed significantly lower risk of ischemic stroke compared with dabigatran (odds ratio, 0.15 and 0.12, respectively) in standard doses. The delayed bleeding developed after gastroduodenal ESD in 7.6%, 14.6%, 19.2%, and 17.3% of patients taking each DOAC, respectively, with the lowest risk in dabigatran, followed by rivaroxaban. A similar pattern was observed in delayed bleeding in esophageal ESD (3.2%, 5.4%, 7.5%, and 5.5% in each DOAC), but with no significant results.

CONCLUSIONS

Rivaroxaban might be an optimal DOAC for upper gastrointestinal ESD showing a lower risk for both ischemic stroke and delayed bleeding.

Comparison of clinical outcomes between conventional and underwater endoscopic mucosal resection for duodenal neuroendocrine tumors

Duodenal neuroendocrine tumors are relatively rare subepithelial tumors that arise from cells of the neuroendocrine system. Small duodenal neuroendocrine tumors can be treated endoscopically because of their low potential for metastasis. This study aimed to evaluate the clinical outcomes of conventional and underwater endoscopic mucosal resection for duodenal neuroendocrine tumors. Between March 2009 and March 2023, 15 patients with duodenal neuroendocrine tumors resected using conventional (n = 7) and underwater (n = 8) endoscopic mucosal resections were retrospectively enrolled. The median specimen size and median tumor size were 1.0 cm (interquartile range: 0.8-1.2 cm) and 0.6 cm (interquartile range: 0.4-0.6 cm), respectively. More than half of duodenal neuroendocrine tumors were located in the duodenal bulb (9/15, 60%). The en bloc and complete resection rates of both conventional and underwater endoscopic mucosal resections were 100%. Only one perforation event occurred in the conventional endoscopic mucosal resection group (14.3%). The patient with the perforation was treated with endoscopic clipping. The median follow-up period was 39.5 months (interquartile range: 19.5-57.3 months). There was no local recurrence or distant metastasis during the follow-up period. Underwater endoscopic mucosal resection is a safe and effective treatment option for small duodenal neuroendocrine tumors and is the preferred treatment option for flat-type duodenal neuroendocrine tumors.

Risk factor analysis and predictive model construction for postoperative bleeding in early esophageal cancer

OBJECTIVE

A multivariate logistic regression model was developed to identify the risk factors for postoperative bleeding in patients undergoing endoscopic submucosal dissection (ESD) for early esophageal cancer.

METHODS

The clinical data of 258 patients with early esophageal cancer who received ESD in Jiujiang Number One People's Hospital from April 2019 to March 2022 were retrospectively analyzed. Patients with or without postoperative bleeding were included into a bleeding group and a control group, respectively, and general information with statistically significant difference between the two groups was included in the multivariate logistic regression model to screen the risk factors for postoperative bleeding in the patients. The risk factors were then used to construct a nomogram prediction model for postoperative bleeding, and internal (training set) and external (validation set) validation was performed.

RESULTS

(1) The incidence of post-ESD bleeding was 12.02% in the 258 patients with early esophageal cancer. (2) History of hypertension, lesion diameter, submucosal fibrosis, C-reactive protein (CRP), and albumin (ALB) were independent risk factors for postoperative bleeding after ESD in the patients (P<0.05). (3) The results of receiver operator characteristic curve (ROC) showed that the area under the curve (AUC) was 0.821 for the training set and 0.740 for the validation set. (4) The correction curve showed that the actual and predicted values of the training and validation sets were well fitted.

CONCLUSION

Hypertension history, lesion diameter, submucosal fibrosis, CRP, and ALB are risk factors for postoperative bleeding in patients with early esophageal cancer undergoing ESD. The nomograms established based on these factors has good predictive value for postoperative bleeding in these patients.

A pilot study on endoscopic delivery of injectable bioadhesive for esophageal repair in a porcine model

Endoscopic submucosal dissection (ESD) is the gold-standard surgical procedure for superficial esophageal cancer. A significant and challenging complication of this technique is post-ESD esophageal stricture. In this study, the feasibility of endoscopic catheter delivery of bioadhesive to esophageal lesions in a porcine model was tested. Injectable bioadhesive was composed of oxidized dextran (ODA) and chitosan hydrochloride (CS), its physicochemical properties, injectability, antibacterial activity, and cytocompatibility were investigated beforein vivotest. ODA-CS bioadhesive was delivered to the wound bed of the esophageal tissue using a custom-made catheter device after ESD in a porcine model. Our results show that the ODA-CS bioadhesive is of good injectability, tissue adhesive strength, antibacterial capacity, and blood compatibility.In vivodelivery was achieved by endoscopic spraying of ODA and CS in separate catheters fixed on the endoscopic probe. ODA and CS can be mixed well to allow in situ bioadhesive formation and firmly adhere to the esophageal wound surface. After two weeks, the bioadhesive maintained structural integrity and adhered to the surface of esophageal wounds. However, histological analysis reveals that the ODA-CS bioadhesive did not show improvement in attenuating inflammatory response after ESD. This pilot study demonstrates the feasibility of ODA-CS bioadhesive for shielding esophageal wounds after ESD, whereas efforts need to improve its anti-inflammatory activity to reduce fibrosis for stricture prevention.

Efficacy of robot arm-assisted endoscopic submucosal dissection in live porcine stomach (with video)

Endoscopic submucosal dissection (ESD) is technically challenging and requires a high level of skill. However, there is no effective method of exposing the submucosal plane during dissection. In this study, the efficacy of robot arm-assisted tissue traction for gastric ESD was evaluated using an in vivo porcine model. The stomach of each pig was divided into eight locations. In the conventional ESD (C-ESD) group, one ESD was performed at each location (N = 8). In the robot arm-assisted ESD (R-ESD) group, two ESDs were performed at each location (N = 16). The primary endpoint was the submucosal dissection speed (mm2/s). The robot arm could apply tissue traction in the desired direction and successfully expose the submucosal plane during submucosal dissection in all lesion locations. The submucosal dissection speed was significantly faster in the R-ESD group than in the C-ESD group (p = 0.005). The blind dissection rate was significantly lower in the R-ESD group (P = 0.000). The robotic arm-assisted traction in ESD enabled a significant improvement in submucosal dissection speed, blind dissection rate which suggests the potential for making ESD easier and enhancing procedural efficiency and safety.

Widespread use of proton pump inhibitors or potassium-competitive acid blocker has changed the status of gastrointestinal bleeding in patients with ischemic heart disease: real-world data from high volume centers

BACKGROUND

Although proton pump inhibitors (PPIs) or potassium-competitive acid blocker (PCAB) are useful in peptic ulcer prevention, their efficacy in preventing other gastrointestinal bleeding remains unclear. This study aimed to identify the status of gastrointestinal bleeding in the modern era when PPIs are widely used.

METHODS

This study included patients who underwent percutaneous coronary intervention (PCI) between 2018 and 2019 at two high-volume centers. Patients were categorized based on whether they experienced gastrointestinal bleeding within 2 years of PCI into groups A (patients who experienced gastrointestinal bleeding within 2 years after PCI) and B (patients who did not experience gastrointestinal bleeding).

RESULTS

Groups A and B included 21 (4.1%) and 494 (95.9%) patients, respectively (a total of 515 patients). Age at the initial PCI (77.8±2.4 and 72.0±0.5 years in groups A and B, respectively; p = 0.02), weight (53.8±3.2 and 61.8±0.7 kg in groups A and B, respectively; p = 0.01), and concomitant warfarin use (14.3% and 2.0% in groups A and B, respectively; p = 0.0005) were significantly different between the groups. The high bleeding risk rate (90.5% and 47.6% in groups A and B, respectively; p = 0.0001) was significantly different between the groups. A total of 95.9% of patients were taking PPIs or PCAB without significant differences between the groups. However, only one patient, who was taking steroids, had a gastric ulcer during PCAB treatment.

CONCLUSIONS

Acid-related upper gastrointestinal bleeding is largely controlled by PPIs in post-PCI patients. Furthermore, the risk factors for non-acid-related bleeding include older age, lower weight, and concomitant warfarin use.

Characteristics and Risk Factors of Delayed Perforation in Endoscopic Submucosal Dissection for Early Gastric Cancer

(1) Background: Delayed perforation after gastric endoscopic submucosal dissection (ESD) for early gastric cancer is a relatively uncommon and serious complication that sometimes requires emergency surgery. This study aimed to determine the clinicopathological features, risk factors, and appropriate management strategies for delayed perforation. (2) Methods: This study included 735 patients with 791 lesions who underwent ESD for early gastric cancer at a single institution between July 2009 and June 2019. We retrospectively compared the clinical features of patients with and without delayed perforations. (3) Results: The incidence of delayed perforations was 0.91%. The identified risk factors included a postoperative stomach condition and histopathological ulceration. A comparison between delayed and intraoperative perforations revealed a postoperative stomach condition as a characteristic risk factor for delayed perforation. Patients with delayed perforation who avoided emergency surgery tended to exhibit an earlier onset of symptoms such as abdominal pain and fever. No peritoneal seeding following delayed perforation was observed for any patient. (4) Conclusions: A postoperative stomach condition and histopathological ulceration were risk factors for delayed perforation. Delayed perforation is a significant complication that requires careful monitoring after gastric ESD for early gastric cancer, particularly in patients with postoperative gastric conditions.

Underwater clip closure method for mucosal defects after duodenal endoscopic submucosal dissection (with video)

Conventional clip closure of mucosal defects after duodenal endoscopic submucosal dissection decreases the incidence of delayed adverse events, but may result in incomplete closure, depending on size or location. This study aimed to assess the effectiveness of the underwater clip closure method for complete duodenal defect closure without the difficulties associated with conventional closure methods. We investigated 19 patients with 20 lesions who underwent endoscopic submucosal dissection of the duodenum and subsequent mucosal defect closure in underwater conditions at our facility between February 2021 and January 2022. The success rate of the underwater clip closure method was defined as the complete endoscopic closure of the mucosal defect; a success rate of 100% was achieved. The median resected specimen size was 34.3 mm, the median procedure time for mucosal defect closure was 14 min, and the median number of clips used per patient was 12. No delayed adverse events were observed. The underwater clip closure method is a feasible option for complete closure of mucosal defects, regardless of the size or location of a duodenal endoscopic submucosal dissection.

Endoscopic submucosal dissection for early gastric cancer: It is time to consider the quality of its outcomes

Endoscopic resection, particularly endoscopic submucosal dissection (ESD), is widely used as a standard treatment modality for early gastric cancer (EGC) when the risk of lymph node metastasis is negligible. Compared with surgical gastrectomy, ESD is a minimally invasive procedure with additional advantages, such as preservation of the entire stomach and maintenance of the patient's quality of life. However, not all patients achieve curative resection after ESD of EGC. Several patients require surgical gastrectomy after ESD to achieve a curative treatment. Additional surgery after ESD, owing to non-curative resection, places considerable emotional and financial burdens on patients. Recently, as the number of endoscopists performing ESD has increased, the rate of non-curative resection after ESD has increased correspondingly. In order to decrease the non-curative resection rate, as well as determine the ideal rate of non-curative resection after ESD, it is time to consider quality indicators for the outcomes of ESD for EGC.

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.

Hybrid Dry Powders for Rapid Sealing of Gastric Perforations under an Endoscope

Effective wound sealing is key to prevent postoperative complications arising from gastric endoscopic submucosal dissection (ESD). Accurate delivery of the adhesive to wet and dynamic tissues and rapid action of the adhesive onsite should be considered for endoscopic operation. A hybrid dry powder (HDP) strategy, characterized by decoupling of powder gelation and tissue adhesion, for rapid sealing of wet tissues is presented. HDPs carrying oppositely charged polyelectrolytes become a hydrogel layer over the target tissue by absorbing the surrounding water and forming strong electrostatic interactions between heterogeneous components. Strong adhesion is realized through hydrogen bonding between the adhesive component, poly(acrylic acid), and the tissue. Wet tissue adhesion can be achieved in a few seconds (adhesion strength of ∼30 kPa to porcine skin). Notably, the HDP-assembled hydrogel can maintain a low swelling rate and resist degradation in acidic aqueous environments (pH 1). Furthermore, HDPs can be delivered to target tissues by spraying via an endoscope. The results of in vivo experiments indicate that healing of gastric ESD perforations by sealing with the powder-assembled hydrogel is as effective as that by sealing with clips. This strategy is expected to facilitate the development of fast-acting hydrogel-based adhesives for endoscopic operation.

Deep Learning for the Diagnosis of Esophageal Cancer in Endoscopic Images: A Systematic Review and Meta-Analysis

Esophageal cancer, one of the most common cancers with a poor prognosis, is the sixth leading cause of cancer-related mortality worldwide. Early and accurate diagnosis of esophageal cancer, thus, plays a vital role in choosing the appropriate treatment plan for patients and increasing their survival rate. However, an accurate diagnosis of esophageal cancer requires substantial expertise and experience. Nowadays, the deep learning (DL) model for the diagnosis of esophageal cancer has shown promising performance. Therefore, we conducted an updated meta-analysis to determine the diagnostic accuracy of the DL model for the diagnosis of esophageal cancer. A search of PubMed, EMBASE, Scopus, and Web of Science, between 1 January 2012 and 1 August 2022, was conducted to identify potential studies evaluating the diagnostic performance of the DL model for esophageal cancer using endoscopic images. The study was performed in accordance with PRISMA guidelines. Two reviewers independently assessed potential studies for inclusion and extracted data from retrieved studies. Methodological quality was assessed by using the QUADAS-2 guidelines. The pooled accuracy, sensitivity, specificity, positive and negative predictive value, and the area under the receiver operating curve (AUROC) were calculated using a random effect model. A total of 28 potential studies involving a total of 703,006 images were included. The pooled accuracy, sensitivity, specificity, and positive and negative predictive value of DL for the diagnosis of esophageal cancer were 92.90%, 93.80%, 91.73%, 93.62%, and 91.97%, respectively. The pooled AUROC of DL for the diagnosis of esophageal cancer was 0.96. Furthermore, there was no publication bias among the studies. The findings of our study show that the DL model has great potential to accurately and quickly diagnose esophageal cancer. However, most studies developed their model using endoscopic data from the Asian population. Therefore, we recommend further validation through studies of other populations as well.

Bleeding following Endoscopic Submucosal Dissection for Early Gastric Cancer in Surgically Altered Stomach

INTRODUCTION

Few studies have focused on bleeding following endoscopic submucosal dissection (ESD) in surgically altered stomach. We aimed to reveal the bleeding risk in surgically altered stomach following ESD for early gastric cancer (EGC).

METHODS

We enrolled patients with ESD for EGC at 33 institutions between 2013 and 2016. In study 1, we evaluated bleeding risk following ESD in surgically altered stomach, compared with whole stomach. In study 2, we evaluated factors associated with bleeding following ESD in patients with surgically altered stomach.

RESULTS

Of 11,452 patients, 445 patients had surgically altered stomach with the bleeding rate following ESD of 4.9%. In study 1, the bleeding risk in surgically altered stomach was not significant (odds ratio [OR], 1.37; 95% confidence interval [CI], 0.87-2.17) in the multivariate logistic regression analysis. No significant results were obtained when the surgically altered stomach was subdivided into various types. In study 2, the multivariate logistic regression analysis revealed that independent risk factors for bleeding following ESD were ischemic heart disease (OR, 7.52; 95% CI, 2.00-28.25) and P2Y12 receptor antagonist (OR, 4.81; 95% CI, 1.21-19.14).

DISCUSSION/CONCLUSION

In this nationwide study, we found that the bleeding risk of surgically altered stomach following ESD for EGC did not significantly differ from that of whole stomach. The risk factors for ESD in patients with surgically altered stomach were ischemic heart disease and P2Y12 receptor antagonist.

Management of Superficial Esophageal Squamous Cell Carcinoma and Early Gastric Cancer following Non-Curative Endoscopic Resection

According to the European and Japanese guidelines, additional treatment is recommended for cases of superficial esophageal squamous cell carcinoma (ESCC) and early gastric cancer (EGC) that do not meet the curability criteria for endoscopic resection (ER), i.e., non-curative ER, owing to the risk of lymph node metastasis (LNM). However, the rates of LNM in such cases were relatively low (e.g., 8% for EGC). Several recent advances have been made in this field. First, pathological risk stratification for metastatic recurrence following non-curative ER without additional treatment was developed for both superficial ESCC and EGC. Second, the pattern of metastatic recurrence and prognosis after recurrence following non-curative ER without additional treatment was found to be considerably different between superficial ESCC and EGC. Third, a combination of ER and selective chemoradiotherapy was developed as a minimally invasive treatment method for clinical T1b-SM ESCC. These findings may help clinicians decide the treatment strategy for patients following non-curative ER; however, for optimal therapeutic decision-making in such patients, it is also important to predict the prognosis other than SESCC or EGC and impaired quality of life. Thus, a novel algorithm that considers these factors, as well as metastatic recurrence, should be developed.