Widespread endoscopic mucosal resection of the esophagus with strategies for stricture prevention: a preclinical study

Strategies for Preventing Esophageal Stenosis After Endoscopic Submucosal Dissection and Progress in Stem Cell-Based Therapies

Endoscopic submucosal dissection (ESD) has been widely used in the early neoplasia of the esophagus. However, postoperative esophageal stenosis is a big problem, particularly when a large circumferential proportion of esophageal mucosa is resected. Currently, there are several methods available to prevent esophageal stenosis after ESD, including steroid administration, esophageal stent implantation, and endoscopic balloon dilation (EBD). However, the therapeutic effects of these are not yet satisfactory. Stem cell-based therapies has shown promising potential in reconstructing tissue structure and restoring tissue function. In this study, we discussed the current strategies for preventing esophageal stenosis after ESD and perspectives of stem cell-based therapies for the prevention of esophageal stenosis.

Intralesional steroid infusion using a spray tube to prevent stenosis after endoscopic submucosal dissection of esophageal cancer

Background/Aims

Intralesional steroid injections have been administered as prophylaxis for stenosis after esophageal endoscopic submucosal dissection. However, this method carries a risk of potential complications such as perforation because a fine needle is used to directly puncture the postoperative ulcer. We devised a new method of steroid intralesional infusion using a spray tube and evaluated its efficacy and safety.

Methods

Intralesional steroid infusion using a spray tube was performed on 27 patients who underwent endoscopic submucosal dissection for superficial esophageal cancer with three-quarters or more of the lumen circumference resected. The presence or absence of stenosis, complications, and the number of endoscopic balloon dilations (EBDs) performed were evaluated after treatment.

Results

Although stenosis was not observed in 22 of the 27 patients, five patients had stenosis and dysphagia requiring EBD. The stenosis in these five patients was relieved after four EBDs. No complications related to intralesional steroid infusion using the spray tube were observed.

Conclusions

Intralesional steroid infusion using a spray tube is a simple and safe technique that is adequately effective in preventing stenosis (clinical trial number, UMIN000037567).

Clinical effectiveness of short course oral prednisone for stricture prevention after semi-circumferential esophageal endoscopic submucosal dissection

Background and study aims  Esophageal strictures (ES) occur frequently after semi-circumferential endoscopic submucosal dissection (ESD) for the eradication of superficial esophageal neoplasms and negatively impact a patient's quality of life. Oral corticosteroids have been shown to be clinically effective, but the most appropriate drug, dose and duration is yet to be determined. The aim of the study was to investigate the clinical effectiveness and safety of 30 mg prednisone with a shortened tapering schedule on ES after semi-circumferential ESD. Patients and methods  This was a retrospective observational study that analyzed consecutive patients with esophageal neoplasms who underwent semi-circumferential ESD with a resection defect greater than 75 % of the circumference that received a protocol of oral steroids for stricture prevention. On postoperative day 3, 30 mg prednisone was prescribed, tapering weekly to 20 mg/10 mg/5 mg over 4 weeks. Follow-up included clinic consultation and endoscopic review at weeks 2 and 4. Effectiveness outcomes included ES rates, safety, tolerability, resection, dilatation and recurrence rates. Results  Ninety ESD procedures were carried out during the specified time period and 18 patients met the inclusion criteria for the final analysis. The mean age was 61.5 years, lesion size was 52.5 mm, and final histology was squamous cell carcinoma in all patients. Incidence of intra-procedure complications was: bleeding 5.5 % (1/18) and ES 5.5 % (1/18), requiring a median two endoscopic dilatations. En bloc, R0 and curative resection rates were 88.8 %, 72.2 %, and 55.5 %, respectively. Conclusions  The short tapering schedule of 30 mg oral prednisone is clinically efficacious and safe for prevention of ES after semi-circumferential ESD in Latin American patients.

Recent Advances of Biomedical Materials for Prevention of Post-ESD Esophageal Stricture

Esophageal stricture commonly occurs in patients that have suffered from endoscopic submucosal dissection (ESD), and it makes swallowing difficult for patients, significantly reducing their life qualities. So far, the prevention strategies applied in clinical practice for post-ESD esophageal stricture usually bring various inevitable complications, which drastically counteract their effectiveness. Nowadays, with the widespread investigation and application of biomedical materials, lots of novel approaches have been devised in terms of the prevention of esophageal stricture. Biomedical polymers and biomedical-derived materials are the most used biomedical materials to prevent esophageal stricture after ESD. Both of biomedical polymers and biomedical-derived materials possess great physicochemical properties such as biocompatibility and biodegradability. Moreover, some biomedical polymers can be used as scaffolds to promote cell growth, and biomedical-derived materials have biological functions similar to natural organisms, so they are important in tissue engineering. In this review, we have summarized the current approaches for preventing esophageal stricture and put emphasis on the discussion of the roles biomedical polymers and biomedical-derived materials acted in esophageal stricture prevention. Meanwhile, we proposed several potential methods that may be highly rational and feasible in esophageal stricture prevention based on other researches associated with biomedical materials. This review is expected to offer a significant inspiration from biomedical materials to explore more effective, safer, and more economical strategies to manage post-ESD esophageal stricture.

Extracellular vesicles from adipose stromal cells combined with a thermoresponsive hydrogel prevent esophageal stricture after extensive endoscopic submucosal dissection in a porcine model

In this study, we investigated the combination of extracellular (nano) vesicles (EVs) from pig adipose tissue-derived stromal cells (ADSCs) and a thermoresponsive gel, Pluronic® F-127 (PF-127), to prevent stricture formation after endoscopic resection in a porcine model. ADSC EVs were produced at a liter scale by a high-yielding turbulence approach from ADSCs 3D cultured in bioreactors and characterized in terms of size, morphology and membrane markers. The thermoresponsive property of the PF-127 gel was assessed by rheology. The pro-regenerative potency of ADSC EVs was investigated ex vivo in esophageal biopsies under starvation. In vivo tests were performed in a porcine model after extended esophageal endoscopic mucosal dissection (ESD). Pigs were randomized into 3 groups: control (n = 6), gel (n = 6) or a combination of 1.45 × 1012 EVs + gel (n = 6). Application of gel ± EVs was performed just after ESD with a follow-up finalized on day 21 post-ESD. There was a trend towards less feeding disorder in the EV + gel group in comparison with the gel and the control groups (16.67% vs. 66.7% vs. 83.33%, respectively) but without reaching a statistically significant difference. A significant decrease in the esophageal stricture rate was confirmed by endoscopic, radiological and histological examination for the EV + gel group. A decrease in the mean fibrosis area and larger regenerated muscularis mucosae were observed for the EV + gel group. In summary, the application of EVs + gel after extended esophageal endoscopic resection succeeded in preventing stricture formation with an anti-fibrotic effect. This nano-therapy may be of interest to tackle an unmet medical need considering that esophageal stricture is the most challenging delayed complication after extended superficial cancer resection by endoscopy.

Prevention of esophageal stricture after circumferential endoscopic submucosal dissection using a modified self-assembling peptide

Circumferential endoscopic resection (ER) of the esophageal mucosa could find its place in the treatment of dysplastic Barrett's esophagus or extensive squamous cell neoplasia. However, the occurrence of esophageal strictures remains a major complication after ER exceeding 75% of the circumference. The aim of this study was to assess the effect of a modified, pH = 2, self-assembling peptide matrix (4[Arg-Ala-Asp-Ala]) (SAP) on the development of esophageal stricture after circumferential ER in a swine model. We performed a circumferential ER in 35 swine under general anesthesia. Five animals were included in the control group, 11 animals received the SAP matrix immediately after the resection, and 11 received the SAP matrix associated to a local steroid immediately after the resection. Follow-up endoscopy and esophagogram were performed before slaughter and necropsy at day 14. Eight treated animals were kept alive until day 28. At day 14, 27% of the animals in the SAP group developed a symptomatic stricture versus 100% in the control group (P = 0.008) and 50% in the SAP-triamcinolone group (P = 0.11). Application of an SAP matrix after circumferential ER in the swine allowed a significant reduction of the incidence of symptomatic stricture at day 14. Adding triamcinolone brought no significant improvement.

Histological changes in the human esophagus following triamcinolone injection to prevent esophageal stricture after endoscopic submucosal dissection

BACKGROUND

Locoregional steroid injection prevents post-endoscopic submucosal dissection (ESD) esophageal stricture, but histological changes that occur following steroid injection in the human esophagus are unclear. This study investigated the histopathological characteristics caused by locoregional triamcinolone acetonide (TA) injection using human esophagectomy specimens.

METHODS

From January 2014 to December 2019, among 297 patients (373 lesions) who underwent esophageal ESD, 13 patients who underwent additional esophagectomy after ESD were examined. Seven patients (TA group) with wide excisions were injected with TA after ESD and another six patients (Non-TA group) with smaller tumors were not injected with TA. The clinical background of these patients and histopathological features of ESD ulcer scar obtained from esophagectomy specimens were retrospectively investigated.

RESULTS

The circumferential rate of ESD excision was more than three-quarters in all cases in the TA group, whereas it was less than three-quarters in the Non-TA group. No other statistical difference in the clinical background was found between the two groups. The subepithelial fibrous tissue of the ESD ulcer scar in the TA group was significantly thinner than that in the Non-TA group (P < 0.05). There was no significant difference in the thickness of the regenerated epithelium and muscularis propria layer of the ESD ulcer scar.

CONCLUSIONS

Histological finding of thinning of the subepithelial fibrous tissue of ESD ulcer scar in the human esophagus after TA injection was obtained. This suggests that TA suppresses the proliferation of the fibrous tissue of the subepithelial layer to help prevent esophageal stricture after widespread ESD in the human esophagus.

Effectiveness of fibrin sealant as a hemostatic technique in accelerating endoscopic submucosal dissection-induced ulcer healing and preventing stricture in the esophagus: A retrospective study

The aim of the present retrospective study was to evaluate the effectiveness of conservative electrocoagulation followed by porcine fibrin sealant (FS) as a protective hemostatic technique for wounded microvessels in promoting the healing of endoscopic submucosal dissection (ESD)-induced ulcer, and preventing esophageal strictures that follow ESD. A total of 203 patients with early esophageal cancer or precancerous lesions were retrospectively analyzed. The 1-month ulcer healing and stricture rates were compared between the two groups (combined hemostats and electrocautery groups). The 1-month complete healing rate was 77.0% in the combined hemostats group and 52.6% in the electrocautery group (P=0.003). The use of FS and a smaller resected range (<3/4 circumference) was associated with a better 1-month healing rate. For patients with a ≥3/4 circumference mucosal defect, the esophageal stricture rate was 31.6% (6/19) in the combined hemostats group and 25.0% (2/8) in the electrocautery group. There was no difference in the stricture rate (P=0.737) and dilation time (P=0.733) between the two groups. In conclusion, the application of conservative electrocoagulation followed by porcine FS as a wound-protection technique promoted ESD-induced ulcer healing in the esophagus. However, this combined hemostatic technique was not superior to the conventional hemostatic method in preventing post-ESD stricture in patients with large esophageal mucosal defects.

Prospective multicenter study of the esophageal triamcinolone acetonide-filling method in patients with subcircumferential esophageal endoscopic submucosal dissection

BACKGROUND AND AIM

The esophageal triamcinolone acetonide (TA)-filling method is a novel local approach for stenosis prevention after extensive esophageal endoscopic submucosal dissection (ESD). We evaluated this method after subcircumferential ESD.

METHODS

We enrolled 20 patients with esophageal cancer requiring subcircumferential ESD in a prospective multicenter study. Esophageal TA filling was carried out 1 day and 1 week after ESD, with follow-up endoscopy every 2 weeks. We treated severe stenosis preventing endoscope passage with endoscopic balloon dilatation (EBD) and additional TA filling, and mild stenosis allowing endoscope passage with additional TA filling only. Primary endpoint was incidence of severe stenosis; secondary endpoints were total number of EBD, rate of additional TA filling, time to stenosis and complete re-epithelialization, dysphagia score, and adverse events. Horizontal resection grade was divided into grades 1 (≥ 9/12 and <10/12 of the circumference), 2 (≥ 10/12 and <11/12), and 3 (≥ 11/12 but not circumferential) and analyzed statistically for correlation with endpoints.

RESULTS

Incidence of severe stenosis was 5.0% (1/20; 0.1-24.8%) and was treated with three EBD. Six patients showed mild stenosis. Additional TA filling was carried out in these seven patients: 0% (0/9) for grade 1 resection, 40% (2/5) for grade 2, and 83% (5/6) for grade 3 (P < 0.05). Median time to stenosis and re-epithelialization was 3 and 7 weeks, respectively. Dysphagia score deteriorated in one patient. No adverse events occurred.

CONCLUSIONS

The esophageal TA-filling method prevented stenosis after subcircumferential ESD. Grade ≥2 resection showed a high risk for stenosis, but additional TA filling for mild stenosis inhibited stenosis progression (UMIN000024384).

Efficacy of hydrocortisone sodium succinate and aluminum phosphate gel for stricture prevention after ≥3/4 circumferential endoscopic submucosal dissection

Objective

Endoscopic submucosal dissection (ESD) is widely used in early-stage esophageal cancer, but the quality of life of patients with postoperative stricture is markedly reduced, requiring long-term repeat, periodic endoscopic balloon dilatation. We evaluated the combination of hydrocortisone sodium succinate and aluminum phosphate gel administered orally for stricture prevention.

Methods

We retrospectively assigned 27 patients who underwent ≥3/4 circular ESD for esophageal superficial squamous cell cancer to one of two groups according to the preventative strategy: endoscopic intralesional steroid injection and systemic steroid (IT+ST group) and oral combination of hydrocortisone sodium succinate and aluminum phosphate gel (OHA group). Stricture rate was compared between the two groups.

Results

There were six and seven complete and ≥3/4 circular ESD cases, respectively, in the IT+ST group and four and ten cases in the OHA group. Stricture rates in the IT+ST and OHA groups were 53.8% and 7.1%, respectively. Nine patients in each group developed hypokalemia after glucocorticoid administration.

Conclusions

OHA is a promising treatment strategy for stricture prevention following large-circumference ESD in patients with early stage esophageal carcinoma.

Strategies to prevent stricture after esophageal endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) has been widely applied as a less invasive and more effective method for treating early esophageal cancers such as squamous cell carcinoma and dysplasia of Barrett's esophagus. However, post-ESD esophageal stricture often occurs if patients suffer circumferential mucosal defects of more than three-quarters of the circumference of the esophagus, which makes it difficult for patients to swallow and greatly reduces their quality of life. Moreover, there is currently no standard method to treat post-ESD esophageal stricture, even though it is extraordinarily important to prevent its formation. In recent years, several strategies to prevent esophageal stricture have emerged. These strategies can be classified into pharmacological, mechanical, tissue engineering, and other novel strategies, with each strategy having its own strengths and weaknesses. Although the pharmacological prophylaxis and mechanical strategies are relatively mature, they still have their drawbacks like high time-consumption, the occurrence of re-stricture, and significant side effects. Tissue engineering strategies and other novel strategies have shown promising preliminary results, but more clinical trials are needed. In this review, we discuss these strategies, with a particular focus on tissue engineering strategies and other novel strategies. It is hoped that this discussion will aid in finding more effective and safer strategies to prevent esophageal stricture.

Efficacy and safety of steroid in the prevention of esophageal stricture after endoscopic submucosal dissection: A network meta-analysis

BACKGROUND AND AIM

Even though endoscopic submucosal dissection is an important endoscopic resection technique for gastrointestinal neoplasms, there are chances that postoperative esophageal stricture might take place as a side effect. Steroid applications were reported to be effective for the prevention of stricture formation. Therefore, this study aims to evaluate the efficacy and safety of different steroid applications.

METHODS

Eligible studies published on PubMed, the Cochrane Library, Embase, Web of Science, and Chinese Biomedical Literature Database before August 2018 were reviewed. The preventions were divided as placebo/no treatment, long-term oral steroid (LOS), median-term oral steroid, short-term oral steroid, single-dose steroid injection, multiple-dose steroid injection, topical superficial steroid, steroid injection combined with oral steroid, and preemptive endoscopic balloon dilatation. The primary outcomes were postoperative esophageal stricture rate and endoscopic balloon dilatation sessions required. Complications were also analyzed.

RESULTS

A total of 19 studies were included. The network meta-results illustrated that compared with the placebo, all kinds of steroid interventions were associated with lower rates of postoperative esophageal stenosis and less number of endoscopic balloon dilatation sessions. Moreover, combined therapy was no better than single regimen therapy. No significant differences between various steroid applications in the incidence of complications were spotted during this study. Based on the results of the network and clustered ranking, LOS might be the superior prevention for postoperative stricture with satisfying efficacy.

CONCLUSION

The present study showed that LOS appears to be the optimal prevention method for postoperative stricture formation.

Autologous Flap Transfer for Esophageal Stricture Prevention After Endoscopic Submucosal Dissection in a Porcine Model

BACKGROUND

Esophageal stricture caused by endoscopic submucosal dissection for a mucosal defect that covers more than three quarters of the circumference of the esophagus has a high incidence. To date, no method for preventing such strictures has been widely recognized as effective in clinical practice.

AIMS

We examined whether esophageal stricture caused by circumferential endoscopic submucosal dissection could be prevented by autologous flap transfer.

METHODS

Six pigs (N = 6) underwent circumferential esophageal endoscopic submucosal dissection under general anesthesia. For animals in the flap group (N = 3), an autologous flap was constructed and then placed at the resection site and secured with metal clips. Animals in the control group (N = 3) underwent endoscopic submucosal dissection only. Endoscopy was performed 3 weeks postoperative to evaluate the effects of flap transfer.

RESULTS

Animals in the flap group gained more weight than animals in the control group. At 3 weeks postoperative, animals in the flap group developed clinically slight stricture; in these animals, an endoscope could be passed through the stricture with slight resistance. In contrast, in the control group, significant stricture was observed, and the stricture was difficult to cross with an endoscope.

CONCLUSION

Autologous flap transfer after circumferential esophageal endoscopic submucosal dissection is a novel approach that remarkably decreases the degree of esophageal stricture that arises.

Progress on the Prevention of Esophageal Stricture after Endoscopic Submucosal Dissection

Endoscopic submucosal dissection (ESD) has been widely accepted as an effective, minimally invasive treatment for superficial esophageal cancers. However, esophageal stricture often occurs in patients with large mucosal defects after ESD. In this review, we discuss various approaches recently researched to prevent esophageal strictures after ESD. These approaches can be classified as pharmacological treatments, esophageal stent treatments, and tissue engineering approaches. Most of the preventive approaches still have their limitations and require further research. With the improvement of current therapies, ESD can be more widely utilized as a minimally invasive treatment with minimal complications.

Esophageal triamcinolone acetonide-filling method: a novel procedure to prevent stenosis after extensive esophageal endoscopic submucosal dissection (with videos)

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) for extensive esophageal carcinomas may cause severe stenosis requiring endoscopic balloon dilations (EBDs). A standard prevention method has not been established. We propose the esophageal triamcinolone acetonide (TA)-filling method as a novel local steroid administration procedure.

METHODS

We enrolled 22 consecutive patients with early esophageal cancer who were treated using either subcircumferential or circumferential ESD (15 and 7 procedures, respectively) in this case series. Esophageal TA filling was performed on the day after ESD and 1 week later and was performed again if mild stenosis was found on follow-up. EBD with TA filling was performed only for severe stenosis that prevented endoscope passage. The primary endpoint was the incidence of severe stenosis. Secondary endpoints were the total number of EBDs and additional TA filling, dysphagia score, time to stenosis and to complete re-epithelialization, and any adverse events.

RESULTS

The incidence of severe stenosis was 4.5% (1/22; confidence interval, .1%-22.8%), and EBD was performed 2 times in 1 patient. Mild stenosis was found in 9 patients. Additional TA filling was performed in 45.5% of patients (10/22; median, 5 times; range, 1-13). The dysphagia score deteriorated to 1 to 2 in 31.8% (7/22) but showed a final score of 0 after complete re-epithelialization in 90.9% (20/22). The median time to stenosis was 3 weeks (range, 3-4) and that to complete re-epithelialization was 7 weeks (range, 4-36). No severe adverse events occurred.

CONCLUSIONS

The esophageal TA-filling method is highly effective for preventing severe stenosis after extensive esophageal ESD.

Polyglycolic acid sheet and fibrin glue for preventing esophageal stricture after endoscopic submucosal dissection: a historical control study

There have been several reports that steroid administration is effective at preventing strictures after endoscopic submucosal dissection (ESD). However, adverse events after steroid use are of great concern. We have reported that shielding with a polyglycolic acid (PGA) sheet and fibrin glue can be useful for prevention of stricture after ESD. We conducted a retrospective analysis of efficiency of shielding with a PGA sheet and fibrin glue for prevention of esophageal stricture compared with intralesional steroid injection. ESD was performed on a total of 489 lesions in 400 patients for superficial esophageal cancer from January 2012 to July 2016. Of these, 39 lesions were enrolled in the study group (PGA sheet and fibrin glue) and 31 lesions were enrolled in the control group. The incidence of postoperative stricture at 6 weeks and the number of sessions of endoscopic balloon dilatation (EBD) required to resolve any strictures were evaluated. The post-ESD stricture rate was 9.1% in the study group (3/33 patients), which was not significantly lower than the stricture rate of 10.3% in the historical control group (3/29 patients; p = 1.00). The mean number of EBD was 0.057 ± 0.24 in the study group and 1.9 ± 5.1 in the control group, which was not significant (P = 0.95). PGA sheet and fibrin glue appear to be a promising option for the prevention of esophageal stricture similar to the effect of intralesional steroid injection.

Oral administration of conditioned medium obtained from mesenchymal stem cell culture prevents subsequent stricture formation after esophageal submucosal dissection in pigs

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) for esophageal cancer often causes postoperative stricture when more than three fourths of the circumference of the esophagus is dissected. Mesenchymal stem cells are a valuable cell source in regenerative medicine, and conditioned medium (CM) obtained from mesenchymal stem cells reportedly inhibits inflammation. In this study we evaluated whether CM could prevent esophageal stricture after ESD.

METHODS

We resected a semi-circumference of pig esophagus by ESD. We prepared CM gel by mixing with 5% carboxymethyl cellulose and endoscopically applied it onto the wound bed immediately after ESD and on days 8 and 15 (weekly CM group) or administered it orally from days 1 to 4 (daily CM group). We also injected triamcinolone acetonide into the remaining submucosa immediately after ESD (steroid group). We killed the pigs on day 8 or day 22 to measure the stricture rate and to perform histologic analysis.

RESULTS

Stricture rate in weekly and daily CM groups and steroid groups were significantly lower than in the control group on day 22. Moreover, CM significantly attenuated the number of activated myofibroblasts and fiber thickness on day 22. CM also significantly decreased the infiltration of neutrophils and macrophages compared with the control group on day 8.

CONCLUSIONS

CM gel prevents esophageal stricture formation by suppressing myofibroblast activation and fibrosis after the infiltration of neutrophils and macrophages. Oral administration of CM gel is a promising treatment for the prevention of post-ESD stricture.

Self-assembling peptide matrix for the prevention of esophageal stricture after endoscopic resection: a randomized controlled trial in a porcine model

Esophageal stricture formation after extensive endoscopic resection remains a major limitation of endoscopic therapy for early esophageal neoplasia. This study assessed a recently developed self-assembling peptide (SAP) matrix as a wound dressing after endoscopic resection for the prevention of esophageal stricture. Ten pigs were randomly assigned to the SAP or the control group after undergoing a 5-cm-long circumferential endoscopic submucosal dissection of the lower esophagus. Esophageal diameter on endoscopy and esophagogram, weight variation, and histological measurements of fibrosis, granulation tissue, and neoepithelium were assessed in each animal. The rate of esophageal stricture at day 14 was 40% in the SAP-treated group versus 100% in the control group (P = 0.2). Median interquartile range (IQR) esophageal diameter at day 14 was 8 mm (2.5-9) in the SAP-treated group versus 4 mm (3-4) in the control group (P = 0.13). The median (IQR) stricture indexes on esophagograms at day 14 were 0.32 (0.14-0.48) and 0.26 (0.14-0.33) in the SAP-treated and control groups, respectively (P = 0.42). Median (IQR) weight variation during the study was +0.2 (-7.4; +1.8) and -3.8 (-5.4; +0.6) in the SAP-treated and control groups, respectively (P = 0.9). Fibrosis, granulation tissue, and neoepithelium were not significantly different between the groups. The application of SAP matrix on esophageal wounds after a circumferential endoscopic submucosal dissection delayed the onset of esophageal stricture in a porcine model.

High-density collagen patch prevents stricture after endoscopic circumferential submucosal dissection of the esophagus: a porcine model

BACKGROUND AND AIMS

Extensive excision of the esophageal mucosa by endoscopic submucosal dissection (ESD) frequently evokes a luminal stricture. This study aimed to determine the efficacy of a high-density collagen patch for the prevention of esophageal stricture in extensive ESD.

METHODS

Six pigs underwent circumferential esophageal ESD under general anesthesia. In 3 pigs, artificial ulcers were covered by 2 collagen patches. The other 3 pigs underwent circumferential ESD only.

RESULTS

The 2 collagen patches were settled onto the ulcer surface using a general endoscope and instruments. The collagen patch-treated group showed significantly better patency rates on both the oral and anal sides of the wound area compared with the control group at day 14. The mucosal re-epithelization ratio was significantly promoted, and the extent of mucosal inflammation and fibrosis was significantly decreased with the collagen patch treatment in the wound area. The frequency of cells positive α-smooth muscle actin was significantly reduced in the collagen patch-treated group compared with the control group.

CONCLUSIONS

We have established a high-density collagen device that can reduce the esophageal stricture associated with extensive ESD. This easy-to-handle device would be useful during superficial esophageal cancer treatment by ESD.

Prevention of esophageal strictures after endoscopic submucosal dissection with the injection of botulinum toxin type A

BACKGROUND AND AIMS

The use of endoscopic submucosal dissection (ESD) for management of widespread superficial esophageal squamous carcinoma is closely associated with esophageal stenosis. We investigated the efficacy and feasibility of endoscopic injection of botulinum toxin type A (BTX-A) for preventing esophageal strictures after ESD for superficial esophageal squamous carcinoma.

METHODS

Sixty-seven patients with superficial esophageal squamous cell carcinomas with mucosal defects that exceeded one half of the circumference of the esophagus after ESD treatment were enrolled and randomly divided into 2 groups (group A, n = 33; group B, n = 34). Patients in group A (BTX-A group) were immediately injected with BTX-A after ESD, whereas patients in group B (control group) received ESD only. Endoscopy was performed when patients reported dysphagia symptoms and at 12 weeks post-ESD in patients without symptoms. Patients who experienced post-ESD esophageal strictures in both groups received bougie dilation.

RESULTS

The number of patients who experienced esophageal strictures in group A (per protocol analysis, 6.1%, 2/33; intention to treat analysis, 11.4%, 4/35) was significantly less than that seen in group B (per protocol analysis, 32.4%, 11/34; intention to treat analysis, 37.8%, 14/37) (P < .05). Moreover, the number of bougie dilation procedures was significantly lower in group A (mean, 1.5; range, 0-2) than in group B (mean, 2.8; range, 0-5) (P < .05).

CONCLUSIONS

Endoscopic injection of BTX-A was effective in preventing post-ESD esophageal strictures and decreasing the times of bougie dilation procedures. (

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR-TRC-12003188.).

A Phase III study of oral steroid administration versus local steroid injection therapy for the prevention of esophageal stricture after endoscopic submucosal dissection (JCOG1217, Steroid EESD P3)

A randomized Phase III trial commenced in Japan in September 2014. Endoscopic local steroid injection has been commonly used and considered acceptable as the current standard treatment for the prevention of esophageal stricture after endoscopic submucosal dissection for superficial esophageal cancer. The purpose of this study is to confirm the superiority of prophylactic oral steroid administration following endoscopic submucosal dissection in terms of stricture-free survival over endoscopic local steroid injection for patients with superficial esophageal cancer. A total of 360 patients will be accrued from 35 Japanese institutions within 2.5 years. The primary endpoint is stricture-free survival, and the secondary endpoints are the number of endoscopic balloon dilations for 12 weeks after endoscopic submucosal dissection, adverse events, serious adverse events and the proportion of patients with dysphagia score ≤1 at 12 weeks after endoscopic submucosal dissection. This trial has been registered in the UMIN Clinical Trials Registry as UMIN000015064 (http://www.umin.ac.jp/ctr/index.htm).

Systematic review: the prevention of oesophageal stricture after endoscopic resection

BACKGROUND

Extensive endoscopic resections for the treatment of early oesophageal neoplasia can result in fibro-inflammatory strictures that require repeated interventions, which significantly alter the patients' quality of life.

AIMS

To review current evidence about the prevention of oesophageal strictures following endoscopic resections.

METHODS

Systematic search of PubMed and Embase from inception to March 2015 using appropriate keywords. All original publications in English were included, and articles on the treatment of oesophageal stricture were excluded.

RESULTS

Of the 461 hits, 62 studies were included in the analysis. Among the wound-protective strategies, polyglycolic acid sheets showed the most convincing evidence with a 37.5% stricture rate and excellent safety. Regenerative medicine, using cell sheets of autologous keratinocytes, resulted in a 25% stricture rate, although with cost and availability concerns. Among anti-proliferative treatment modalities, steroid treatment, either endoscopically injected triamcinolone in the resection wound or orally administered prednisolone, proved effective with an overall stricture rate of 13.5%, with safety concerns regarding late oesophageal perforations and infectious morbidity. Among mechanical treatment options, poorly effective and high-risk preventive balloon dilation tend to be replaced by prophylactic covered stent, with 18-28% stricture rates.

CONCLUSIONS

Although oral or locally injected steroids are promising options, no currently available technique is sufficiently efficient and devoid of significant safety concerns to recommend its routine use for the prevention of strictures after extensive endoscopic resection. Improving our knowledge in the mechanisms of oesophageal wound healing will guide the development of novel methods for stricture prevention.

Locoregional steroid injection prevents stricture formation after endoscopic submucosal dissection for esophageal cancer: a propensity score matching analysis

BACKGROUND

Although endoscopic submucosal dissection (ESD) has become accepted for the treatment of superficial esophageal cancer, the incidence of stricture formation caused by ESD for widespread lesions is high and leads to a low quality of life. A few studies reported that locoregional steroid injections are useful for the prevention of such stricture formation compared with historical controls. We evaluated the efficacy of prophylactic locoregional steroid injections for stricture formation caused by ESD using quasi-randomized analysis.

METHODS

This matched case-control study included 461 superficial esophageal cancers from 305 patients who underwent ESD between 2006 and 2013. We used two methods of locoregional steroid injection to prevent stricture formation after ESD. A propensity score matching analysis was performed to reduce the effects of a selection bias for steroid injections and other potential confounding factors. In addition, generalized estimating equations were used to analyze repeated measures data. We compared the incidence of stricture formation with or without steroid injections.

RESULTS

Forty-two lesions were treated with locoregional steroid injection (dexamethasone/triamcinolone, 23/19) after ESD and esophageal stricture formation occurred in 36 lesions. Fifty-six lesions treated with or without steroid injections were matched after propensity score matching. Locoregional steroid injection reduced the incidence of stricture formation to 10.7% (3/28) of patients compared with 35.7% (10/28) in the control group (odds ratio 4.63, 95% confidence interval 1.11-19.25, p = 0.035).

CONCLUSIONS

Locoregional steroid injections could be efficient for the prevention of stricture formation after ESD for superficial esophageal cancer.

Regenerative medicine for oesophageal reconstruction after cancer treatment

Removal of malignant tissue in patients with oesophageal cancer and replacement with autologous grafts from the stomach and colon can lead to problems. The need to reduce stenosis and anastomotic leakage after oesophagectomy is a high priority. Developments in tissue-engineering methods and cell-sheet technology have improved scaffold materials for oesophageal repair. Despite the many successful animal studies, few tissue-engineering approaches have progressed to clinical trials. In this Review, we discuss the status of oesophagus reconstruction after surgery. In particular, we highlight two clinical trials that used decellularised constructs and epithelial cell sheets to replace excised tissues after endoscopic submucosal dissection or mucosal resection procedures. Results from the trials showed that both decellularised grafts and epithelial-cell sheets prevented stenosis. By contrast, animal studies have shown that the use of tissue-engineered constructs after oesophagectomy remains a challenge.

Cell sheets engineering for esophageal regenerative medicine

Recently, cell-based therapies, regenerative medicine, and tissue engineering have been progressing rapidly. We have developed a novel strategy for regenerative medicine to recover tissue functions using temperature-responsive cell culture surfaces. To overcome of conventional methods such as the usage of single-cell suspension injection, we have applied transplantable cell sheets fabricated with temperature-responsive culture surfaces for cell delivery. In the field of gastroenterology, transplantable cell sheets from autologous oral mucosal epithelial cells can prevent esophageal stricture following extensive endoscopic mucosal resection.

Amniotic membrane grafts for the prevention of esophageal stricture after circumferential endoscopic submucosal dissection

Background and Aims

The prevention of esophageal strictures following circumferential mucosal resection remains a major clinical challenge. Human amniotic membrane (AM) is an easily available material, which is widely used in ophthalmology due to its wound healing, anti-inflammatory and anti-fibrotic properties. We studied the effect of AM grafts in the prevention of esophageal stricture after endoscopic submucosal dissection (ESD) in a swine model.

Animals and Methods

In this prospective, randomized controlled trial, 20 swine underwent a 5 cm-long circumferential ESD of the lower esophagus. In the AM Group (n = 10), amniotic membrane grafts were placed on esophageal stents; a subgroup of 5 swine (AM 1 group) was sacrificed on day 14, whereas the other 5 animals (AM 2 group) were kept alive. The esophageal stent (ES) group (n = 5) had ES placement alone after ESD. Another 5 animals served as a control group with only ESD.

Results

The prevalence of symptomatic strictures at day 14 was significantly reduced in the AM group and ES groups vs. the control group (33%, 40% and 100%, respectively, p = 0.03); mean esophageal diameter was 5.8±3.6 mm, 6.8±3.3 mm, and 2.6±1.7 mm for AM, ES, and control groups, respectively. Median (range) esophageal fibrosis thickness was 0.87 mm (0.78–1.72), 1.19 mm (0.28–1.95), and 1.65 mm (0.7–1.79) for AM 1, ES, and control groups, respectively. All animals had developed esophageal strictures by day 35.

Conclusions

The anti-fibrotic effect of AM on esophageal wound healing after ESD delayed the development of esophageal stricture in our model. However, this benefit was of limited duration in the conditions of our study.

Endoscopic methods in the treatment of early-stage esophageal cancer

Most patients with early esophageal cancer restricted to the mucosa may be offered endoscopic therapy, which is similarly effective, less invasive and less expensive than esophagectomy. Selection of appropriate relevant treatment and therapy methods should be performed at a specialized center with adequate facilities. The selection of an endoscopic treatment method for high-grade dysplasia and early-stage esophageal adenocarcinoma requires that tumor infiltration is restricted to the mucosa and that there is no neighboring lymph node metastasis. In squamous cell carcinoma, this treatment method is accepted in cases of tumors invading only up to the lamina propria of mucosa (m2). Tumors treated with the endoscopic method should be well or moderately differentiated and should not invade lymphatic or blood vessels. When selecting endoscopic treatments for these lesions, a combination of endoscopic resection and endoscopic ablation methods should be considered.

One-step circumferential endoscopic mucosal cap resection of Barrett's esophagus with early neoplasia

BACKGROUND AND OBJECTIVE

Focal endoscopic mucosal resection (EMR) of visible intraepithelial lesions arising within Barrett's esophagus (BE) may miss synchronous lesions that are not endoscopically apparent. Stepwise radical endoscopic resection would obviate this concern by removing all BE; however, it requires repeated endoscopy which may increase the risk of complications, particularly for patients with circumferential BE. The aim of the study was to evaluate the safety and efficacy of one-step complete circumferential resection of BE by cap-assisted EMR (EMR-C) among patients with circumferential BE and high-grade dysplasia or intramucosal carcinoma.

PATIENTS AND METHODS

Between January 2003 and March 2010, 47 patients with circumferential BE and biopsy-proven high-grade dysplasia or intramucosal cancer underwent EMR-C. We evaluated: (1) complete eradication of neoplasia, (2) complete eradication of metaplasia, and (3) complications including bleeding and esophageal stricture.

RESULTS

Complete eradication of neoplasia and complete eradication of metaplasia were achieved after a median follow-up of 18.4 months in 91% (43/47) of patients. After EMR-C, two patients (one IMC, one invasive cancer) underwent esophagectomy. Histology of the resected specimens showed no residual disease and a T1bN0 lesion, respectively. Two patients had progression of neoplasia. A stenosis occurred in 18 out of 45 patients (40%). All stenoses were treated with dilations and two required temporary placement of a covered stent.

CONCLUSION

One-step complete EMR-C is a safe and effective technique which can be considered in patients with early neoplastic lesions. Although 40% of patients developed dysphagia, this could well be managed endoscopically.

Intralesional steroid injection to prevent stricture after near-circumferential endosopic submucosal dissection for superficial esophageal cancer

Stricture frequently occurs after endoscopic submucosal dissection (ESD) for superficial esophageal carcinoma with near- or whole-circumferential mucosal defects, and post-ESD stricture is difficult to treat and usually requires multiple sessions of endoscopic balloon dilatation. Intralesional steroid injection has previously been used to prevent stricture; however, there have been few experiences with this method after near- or whole-circumferential ESD. We present a case of a single session of intralesional steroid injection performed immediately after near-circumferential ESD to prevent post-ESD stricture. After a follow-up period of 6 months, the patient showed good outcome without dysphagia.

Steroid permeation into the artificial ulcer by combined steroid gel application and balloon dilatation: prevention of esophageal stricture

BACKGROUND AND AIM

Local steroid injection therapy is effective for preventing esophageal stricture after endoscopic submucosal dissection (ESD) but is associated with the risk of puncture-related complications, such as bleeding. We evaluated the effectiveness of the application of triamcinolone acetonide gel following permeation into a large artificial ESD ulcer by balloon dilatation compared with steroid injection.

METHODS

Forty-three patients who underwent ESD for early esophageal cancer approved by the institutional ethics committee and provided consent to participate in this prospective study were divided into two groups using a sealed-envelope randomization method as follows: 23 patients who were treated with local steroid injection and balloon dilatation and 20 patients were treated with steroid application and balloon dilatation. The stricture rate, the number of endoscopic balloon dilatation, and the mean procedure time on postoperative days (PODs) 5, 8, 12, 15, 20, 30, and 60 were analyzed.

RESULTS

No significant difference was found in the stricture rate on PODs 5, 8, 12, 15, 20, 30, and 60 between the two groups. The mean number of endoscopic balloon dilatation procedures performed for treating dysphagia that appeared on or after POD 30 was significantly different between groups (P=0.011). The mean procedure time showed no significant difference. Procedure-related bleeding during the first 30 days was observed more in the local steroid injection group than the gel application group (P=0.02).

CONCLUSIONS

Steroid gel application is an effective way for preventing esophageal stricture after ESD and is more effective compared with local injection in terms of prevention of stricture.

Biodegradable esophageal stent placement does not prevent high-grade stricture formation after circumferential mucosal resection in a porcine model

BACKGROUND

Advanced esophageal dysplasia and early cancers have been treated traditionally with esophagectomy. Endoscopic esophageal mucosectomy (EEM) offers less-invasive therapy, but high-degree stricture formation limits its applicability. We hypothesized that placement of a biodegradable stent (BD-stent) immediately after circumferential EEM would prevent stricturing.

METHODS

Ten pigs (five unstented controls, five BD-stent) were utilized. Under anesthesia, a flexible endoscope with a band ligator and snare was used to incise the mucosa approximately 20 cm proximal to the lower esophageal sphincter. A 10-cm, circumferential, mucosal segment was dissected and excised by using snare electrocautery. In the stented group, an 18-×120-mm, self-expanding, woven polydioxanone stent (ELLA-CS, Hradec-Kralove) was deployed. Weekly esophagograms evaluated for percent reduction in esophageal diameter, stricture length, and proximal esophageal dilation. Animals were euthanized when the stricture exceeded 80% and were unable to gain weight (despite high-calorie liquid diet) or at 14 weeks.

RESULTS

The control group rapidly developed esophageal strictures; no animal survived beyond the third week of evaluation. At 2 weeks post-EEM, the BD-stent group had a significant reduction in esophageal diameter (77.7 vs. 26.6%, p < 0.001) and degree of proximal dilation (175 vs. 131%, p = 0.04) compared with controls. Survival in the BD-stent group was significantly longer than in the control group (9.2 vs. 2.4 weeks, p = 0.01). However, all BD-stent animals ultimately developed clinically significant strictures (range, 4-14 weeks). Comparison between the maximum reduction in esophageal diameter and stricture length (immediately before euthanasia) demonstrated no differences between the groups.

CONCLUSIONS

Circumferential EEM results in severe stricture formation and clinical deterioration within 3 weeks. BD-stent placement significantly delays the time of clinical deterioration from 2.4 to 9.2 weeks, but does not affect the maximum reduction in esophageal diameter or proximal esophageal dilatation. The timing of stricture formation in the BD-stent group correlated with the loss radial force and stent disintegration.

Bone marrow-derived cells participate in the long-term remodeling in a mouse model of esophageal reconstruction

BACKGROUND

The default response of the esophagus to injury includes inflammation and scar tissue formation often leading to stricture. Biologic scaffolds composed of extracellular matrix (ECM) have been associated with the reconstitution of functional esophageal tissue in preclinical studies and clinical case reports of esophageal mucosal resection, anastomotic reinforcement, and full circumferential replacement. However, the mechanisms responsible for this change in the default response to esophageal injury are not fully understood.

METHODS

The objective of the present study was to determine whether bone marrow-derived cells (BMCs) participate in the long-term remodeling of ECM scaffolds in the esophageal location in a mouse model.

RESULTS

BMCs were present in low numbers in remodeling ECM scaffolds. Compared with the untreated control mice, the ECM-implanted animals showed better remodeling of the epithelial layer.

CONCLUSIONS

BMCs are involved in ECM remodeling process during tissue repair after esophageal injury, but the low numbers argue against any significant involvement in the constructive remodeling process.

A pilot study of scheduled endoscopic balloon dilation with oral agent tranilast to improve the efficacy of stricture dilation after endoscopic submucosal dissection of the esophagus

BACKGROUNDS AND AIM

As circumferential or near-circumferential endoscopic submucosal dissection (ESD) for superficial esophageal neoplasms might evoke refractory strictures, multiple sessions of endoscopic balloon dilation (EBD) are required. We aimed to assess the effectiveness and safety of oral agent tranilast with EBD for improving the efficacy of stricture dilation after esophageal ESD.

METHODS

In an open-label prospective study at a single institution, 31 asymptomatic consecutive patients with superficial esophageal squamous cell carcinomas were enrolled from April 2007 to October 2010. After ESD, we performed scheduled EBD (twice weekly for 4 wk) with or without administration of oral agent tranilast for 8 weeks. Thereafter, we added additional EBD on the basis of solid criteria-for example, patient's awareness of vomiting >1/wk and inability of passage of routine endoscope through the ESD site. We compared the rates of post-ESD strictures and the numbers of additional EBD sessions for 48 weeks after ESD and the Dysphagia score between tranilast (T)-group and none (N)-group, based on patients' subjective symptoms, at 16, 24, and 48 weeks after ESD.

RESULTS

The percentage of post-ESD strictures in T-group was significantly lower than that in N-group (P=0.04). The median numbers of additional EBD sessions and Dysphagia score at 16 and 24 weeks after ESD in T-group were significantly smaller than those in N-group (P=0.0138, 0.002, 0.005, respectively). No adverse events and no recurrence were observed.

CONCLUSIONS

We demonstrated for the first time that scheduled EBD combined with oral agent tranilast might be effective and safe for improving the efficacy of stricture dilation after esophageal ESD.

Fabricated autologous epidermal cell sheets for the prevention of esophageal stricture after circumferential ESD in a porcine model

BACKGROUND

Endoscopic submucosal dissection (ESD) is an accepted treatment for early esophageal carcinoma. However, resection of a large mucosal area, as with circumferential ESD, induces severe stricture formation.

OBJECTIVE

To evaluate the efficacy of cultured autologous epidermal cell sheets to prevent severe esophageal constriction after circumferential ESD.

DESIGN

Animal study.

SETTING

University institute.

INTERVENTION

Eight pigs underwent circumferential esophageal ESD while under general anesthesia. In 4 pigs, fabricated autologous epidermal cell sheets were endoscopically transplanted to the central ESD sites immediately after the ESD. The other 4 pigs underwent circumferential ESD only. Necropsy and histological assessment were performed at 1 and 2 weeks post-ESD.

MAIN OUTCOME MEASUREMENTS

Weight gain, degree of mucosal constriction, and histological assessments.

RESULTS

All pigs in the control group showed severe esophageal constriction after 2 weeks. The control and transplanted groups had weight gains of -10.3% and 0.3% (P = .03), respectively, and the mean degrees of constriction were 88% and 56% (P < .01), respectively. Early re-epithelialization and mild fibrosis in the muscularis were observed in the transplanted group.

LIMITATIONS

Animal study, small sample size.

CONCLUSIONS

Fabricated autologous skin epidermal cell sheets would be useful in preventing severe esophageal constriction after circumferential ESD.

Stricture prevention after extended circumferential endoscopic mucosal resection by injecting autologous keratinocytes in the sheep esophagus

BACKGROUND

During the past decades, endoscopic mucosal resection (EMR) has been developed to treat early intramucosal esophageal cancers and dysplastic Barrett's esophagus. The primary drawback of this method is severe postsurgical esophageal stricture formation. The purpose of this preclinical study was to assess strategies for prevention of this major complication by injecting autologous keratinocytes in the EMR mucosal defect in the sheep model.

METHODS

Circumferential, 6-cm-long EMRs were performed in the esophagus of nine sheep. Autologous keratinocytes were harvested 2 weeks before EMR and cultured. Circumferential resection consisted of two opposite hemicircumferential mucosectomies allowing a widespread resection of 24 cm(2). Immediately after EMR, autologous keratinocytes were endoscopically injected in the mucosal defect. Animals were sacrificed after 6 months.

RESULTS

Circumferential EMRs were successfully performed in all animals. There were no intra- or postoperative complications. None of the animals developed strictures. All animals were sacrificed at 6 months as planned. Histological examinations showed fibrotic changes in 10 % (range 0-25 %) of the circumferential muscularis propria interna layer and 7.2 % (range 0-25 %) in the muscularis propria externa layer at the midportion of the EMR. No circumferential transmural fibrosis was identified.

CONCLUSIONS

Prevention of stricture formation after extensive (6-cm long) circumferential EMR of the sheep esophagus can be achieved by injecting autologous keratinocytes into the wound of the resected mucosal segment.

Prevention of esophageal stricture after endoscopic submucosal dissection using tissue-engineered cell sheets

BACKGROUND & AIMS

The use of esophageal endoscopic submucosal dissection (ESD) to remove superficial esophageal neoplasms is gradually becoming more common in Japan. However, large-scale esophageal ESD often requires subsequent multiple balloon dilations to prevent postoperative esophageal stricture. We investigated the safety and efficacy of endoscopic transplantation of tissue-engineered autologous oral mucosal epithelial cell sheets in preventing formation of strictures after ESD.

METHODS

We performed an open-label, single-arm, single-institute study. We collected specimens of oral mucosal tissue from 9 patients with superficial esophageal neoplasms. Epithelial cell sheets were fabricated ex vivo by culturing isolated cells for 16 days on temperature-responsive cell culture surfaces. After a reduction in temperature, these sheets were endoscopically transplanted directly to the ulcer surfaces of patients who had just undergone ESD. All patients were monitored by endoscopy once a week until epithelialization was complete.

RESULTS

Autologous cell sheets were successfully transplanted to ulcer surfaces using an endoscope. Complete re-epithelialization occurred within a median time of 3.5 weeks. No patients experienced dysphagia, stricture, or other complications following the procedure, except for one patient who had a full circumferential ulceration that expanded to the esophagogastric junction.

CONCLUSIONS

Sutureless, endoscopic transplantation of carrier-free cell sheets composed of autologous oral mucosal epithelial cells safely and effectively promotes re-epithelialization of the esophagus after ESD. Patients in this study did not experience any serious complications. This procedure might be used to prevent stricture formation following ESD and improve patients' quality of life. Further study will be needed to show that stricture formation can be prevented.

N-acetylcysteine for the prevention of stricture after circumferential endoscopic submucosal dissection of the esophagus: a randomized trial in a porcine model

Background

Circumferential endoscopic submucosal dissection (CESD) of the esophagus would allow for both the eradication of Barrett’s esophagus and its related complications, such as advanced neoplasia. However, such procedures generally induce inflammatory repair resulting in a fibrotic stricture. N-acetylcysteine (NAC) is an antioxidant that has shown some efficacy against pulmonary and hepatic fibrosis. The aim of our study was to evaluate the benefit of NAC in the prevention of esophageal cicatricial stricture after CESD in a swine model.

Animals and methods

Two groups of six pigs each were subjected to general anesthesia and CESD: after randomization, a first group received an oral NAC treatment regimen of 100 mg/kg/day, initiated one week before the procedure, whereas a second group was followed without any prophylactic treatment. Follow-up endoscopies took place seven, fourteen, twenty-one, and twenty-eight days after CESD. Necropsy, histological assessment of esophageal inflammation, and fibrosis were performed on day 28.

Results

The median esophageal lumen diameter on day 21 (main judgment criterion) was 4 mm (range 2 to 5) in group 1 and 3 mm (range 1 to 7) in group 2 (P = 0.95). No significant difference was observed between the two groups regarding clinical evaluation (time before onset of clinically significant esophageal obstruction), number of dilations, esophageal inflammation and fibrosis, or oxidative stress damage on immunohistochemistry.

Conclusions

Despite its antioxidant effect, systemic administration of NAC did not show significant benefit on esophageal fibrosis in our animal model of esophageal wound healing within the experimental conditions of this study. Since the administered doses were relatively high, it seems unlikely that NAC might be a valuable option for the prevention of post-endoscopic esophageal stricture.

The efficacy of endoscopic triamcinolone injection for the prevention of esophageal stricture after endoscopic submucosal dissection

BACKGROUND

Use of endoscopic submucosal dissection (ESD) for management of widespread superficial esophageal carcinomas may be complicated by the development of severe strictures, which may require serial treatment with endoscopic balloon dilatation (EBD).

OBJECTIVE

The goal of this study was to determine the efficacy of endoscopic triamcinolone injection (ETI) for the prevention of stricture formation after ESD.

DESIGN

Case series.

SETTING

Tertiary-care referral center.

PATIENTS

A total of 41 consecutive patients who had a semi-circumferential mucosal defect that arose after ESD for superficial esophageal squamous cell carcinomas were enrolled in this study.

INTERVENTIONS

EBD and ETI.

MAIN OUTCOME MEASUREMENTS

Incidence of stricture and frequency of required EBD.

RESULTS

ETI was performed in one group of patients (study group, n = 21) but not in the other (control group, n = 20). The incidence of stricture was significantly lower in the study group (19.0%) than in the control group (75.0%; P < .001). The number of required EBDs was also lower in the study group (mean, 1.7; range, 0-15) than in the control group (mean, 6.6; range 0-20). There were no side effects or complications associated with ETI.

LIMITATIONS

Nonrandomized study design and small number of patients in a single endoscopic center.

CONCLUSIONS

This study suggests that ETI is safe and effective for the prevention of esophageal stricture in patients undergoing ESD for superficial esophageal squamous cell carcinomas.

Feasibility study of corticosteroid treatment for esophageal ulcer after EMR in a canine model

BACKGROUND

Intralesional or systemic steroid administration is a promising strategy for the prevention of esophageal stricture after endoscopic therapy. The aim of this study was to evaluate the influence of steroid therapy on the process of healing of defects in the esophageal mucosa after endoscopic mucosal resection (EMR).

METHODS

Nine beagle dogs were divided into three equal groups: group A, intralesional injection (n = 3), group B, peroral administration (n = 3), and group C, untreated control (n = 3). In group A, triamcinolone acetonide 1 ml (10 mg) was injected directly into the exposed submucosal layer immediately after EMR, and again on postoperative day (POD) 7. In group B, dogs were administered prednisolone 0.5 mg/kg/day orally for 14 days after EMR. In group C, 1 ml normal saline was injected by the same method as that used for group A. On POD 28, histological examination was performed to evaluate epithelialization, inflammation, angiogenesis, and atrophy of the muscularis propria.

RESULTS

In groups A, B, and C, the mean ulcer area was 50.1, 22.7, and 7.4 mm(2), respectively. The difference between groups A and C was significant (p < 0.01). Inflammatory cells were significantly more evident in the lesions of group A than in those of group C (p < 0.05). In all groups, atrophy of the muscularis propria was evident. However, transmural destruction and fibrosis were observed only in group A.

CONCLUSION

It was speculated that the esophageal ulcer causes the fibrosis of the submucosa and atrophy of the muscularis propria during process of healing. Intralesional steroid injection deepened the esophageal ulcers and delayed epithelialization, whereas systemic administration did not clearly improve the lesion healing process.

Recent advances in the use of stents for esophageal disease

The use of self-expanding metal esophageal stents has evolved dramatically over the last 20 years. Stents themselves have morphed from simple open-mesh wire devices to a variety of partially and fully covered metal and plastic protheses designed to resist in-growth and migration. Indications include grown considerably from simply palliating malignant dysphagia to the treatment of benign conditions such as refractory strictures, perforations, and fistulas, bridging tumors through neoadjuvant therapy and even serving as support for mucosal healing after ablative therapies. This article describes the current experience with esophageal stenting for malignant and benign conditions and examines new innovations in stent design and applications.

An extracellular matrix scaffold for esophageal stricture prevention after circumferential EMR

BACKGROUND

EMR is an accepted treatment for early esophageal cancer and high-grade dysplasia. One of the limitations of this technique is that extensive mucosal resection and endoscopic submucosal dissection may be required to obtain complete removal of the neoplasm, which may result in significant stricture formation.

OBJECTIVE

The objective of the current study was to evaluate the efficacy of an endoscopically deployed extracellular matrix (ECM) scaffold material for prevention of esophageal stenosis after circumferential EMR.

DESIGN

Ten mongrel dogs were subjected to surgical plane anesthesia and circumferential esophageal EMR by the cap technique. In 5 animals, an ECM scaffold material was endoscopically placed at the resection site; the remaining 5 animals were subjected to circumferential esophageal EMR without ECM placement. Follow-up endoscopy was performed at 4 and 8 weeks; necropsy with histologic assessment was performed at 8 weeks.

SETTING

Animal laboratory.

INTERVENTIONS

Circumferential esophageal EMR by the cap technique, followed by endoscopic placement of an ECM scaffold material.

MAIN OUTCOME MEASUREMENTS

Degree of esophageal stricture and histologic assessment of remodeled esophageal tissue.

RESULTS

All 5 control dogs had endoscopic evidence of esophageal stenosis. Three required early euthanasia because of inability to tolerate oral intake. Incomplete epithelialization and inflammation persisted at the EMR site in control animals. Endoscopic placement of an ECM scaffold material prevented clinically significant esophageal stenosis in all animals. Histologic assessment showed near-normal esophageal tissue with a lack of inflammation or scar tissue at 8 weeks.

CONCLUSIONS

Endoscopic placement of an ECM scaffold material prevented esophageal stricture formation after circumferential EMR in this canine model during short-term observation.

En bloc esophageal mucosectomy for concentric circumferential mucosal resection (with video)

BACKGROUND

With conventional EMR, specimens are fragmented, metaplasia may be left behind, and invasive lesions could be missed because of incomplete sampling. Concentric subtotal esophageal mucosectomy would address these limitations.

OBJECTIVE

To examine en bloc esophageal mucosectomy (EEM).

DESIGN

A prospective case series.

SETTING

An academic hospital.

SUBJECTS

Nine swine.

INTERVENTIONS

Conventional EMR was performed in the proximal esophagus. The submucosal space was entered, and the distal two thirds of the esophageal mucosa was freed with blunt dissection. A snare was threaded over the column of mucosa to the gastroesophageal junction. The column was resected, and the mucosa was retrieved.

MAIN OUTCOME AND MEASUREMENTS

Clinical examination, follow-up endoscopy, necropsy, and gross and histopathologic examination.

RESULTS

EEM permitted subtotal esophageal mucosectomy in 9 of 9 swine (tissue specimens removed ranged 9-15 cm in length). The mean procedure duration was 110 minutes. In the survival series, 4 of 4 swine thrived after surgery, for 9 to 13 days. At 9 days, there was no evidence of a perforation, stricture, or leak. At 13 days, 2 swine had a mild proximal stricture, which was easily traversed with a 9.8-mm gastroscope. On necropsy, the mediastinal and thoracic cavities were unremarkable in 3 of 4 swine. One swine was found to have a contained abscess containing cellulose, presumably secondary to ingestion of wood-chip bedding material postoperatively. Reepithelialization was present on histologic examination.

LIMITATIONS

An animal study.

CONCLUSIONS

EEM is feasible and enabled concentric subtotal esophageal mucosal resection. The technique could completely and circumferentially excise intramucosal lesions. Longer follow-up and larger studies are needed to evaluate infection, stricture, and safety.

Endoscopic mucosal resection in the upper gastrointestinal tract

Endoscopic mucosal resection (EMR) is a technique used to locally excise lesions confined to the mucosa. Its main role is the treatment of advanced dysplasia and early gastrointestinal cancers. EMR was originally described as a therapy for early gastric cancer. Recently its use has expanded as a therapeutic option for ampullary masses, colorectal cancer, and large colorectal polyps. In the Western world, the predominant indication for EMR in the upper gastrointestinal tract is the staging and treatment of advance dysplasia and early neoplasia in Barrett’s esophagus. This review will describe the basis, indications, techniques, and complications of EMR, and its role in the management of Barrett’s esophagus.

Novel techniques and instrumentation for EMR, ESD, and full-thickness endoscopic luminal resection

Endoscopic intervention is evolving into an established therapeutic alternative for small superficial lesions, and an eventual application for en bloc resection of large lesions, deeper layers, and a reliable access to lesions outside of the gastrointestinal wall. Although further developmental and clinical evaluation is necessary, we believe endoscopic resection by the submucosal route and by full-thickness approaches will replace standard surgical procedures in the next several years.

Autologous buccal keratinocyte implantation for the prevention of stenosis after EMR of the esophagus

BACKGROUND

EMR is a minimally invasive and well-accepted therapy for early esophageal cancer. However, extensive or circumferential EMR induces stricture formation. Cultured skin is now clinically applicable by using the technology of regenerative medicine. Esophageal mucosa also consists of keratinocytes, the same as with skin. We, therefore, hypothesized that, by applying the technology of regenerative medicine, the stricture occurring in the esophagus after EMR on broad lesions could be prevented.

OBJECTIVE

The aim of this study was to evaluate, in a swine model, the effect of autologous keratinocyte implantation at the site after EMR to prevent stricture.

DESIGN

With the pig under general anesthesia, EMR was carried out by using the cap technique. Two separate areas were resected by EMR. One area was left as a control. For the other area, autologous buccal keratinocytes were injected endoscopically.

MAIN OUTCOME MEASUREMENTS

The outcome, after 2 weeks, was evaluated by endoscopy, macroscopy, and histology.

RESULTS

At 2 weeks after EMR, scar formation and stricture were observed in the control lesion. However, in the keratinocyte implanted lesion, the lesion was covered with an epithelium and the luminal surface of the lesion was flat, without ulceration.

CONCLUSIONS

These results showed the feasibility of performing autologous keratinocyte implantation after EMR and the effect for early reepithelialization.

Reinforcement of esophageal anastomoses with an extracellular matrix scaffold in a canine model

BACKGROUND

The gastric pull-up procedure, a standard intervention after radical esophagectomy, is associated with high morbidity and mortality due to leaks and stricture. A previous preclinical study showed that an extracellular matrix (ECM) scaffold with autologous muscle tissue could be used to repair a complete circumferential defect in the cervical esophagus. The aim of the present study was to determine if healing of end-to-end anastomoses of the esophagus could be improved by reinforcement with an ECM scaffold.

METHODS

Twelve female mongrel dogs underwent a complete transection of either the cervical esophagus (n = 6) or the gastroesophageal junction (n = 6). A portion of the endomucosa at the anastomotic site was resected and replaced with an ECM scaffold in contact with the subjacent muscle and the muscle was anastomosed. The measured end points included macroscopic and microscopic evaluation and quantification of the esophageal diameter at the anastomotic site.

RESULTS

No anastomotic leaks or systemic complications were observed in the ECM-treated animals. Morphologic findings in both groups showed complete mucosal covering of the surgery site. The remodeled esophageal tissue showed angiogenesis and complete epithelialization. Intact, organized layers of muscle tissue were present between the native muscularis externa and the submucosal layer and effectively bridged the transected ends.

CONCLUSIONS

The ECM scaffold altered the default mechanism of esophageal repair. Scar tissue formation with associated stricture was virtually eliminated, and the esophageal healing response was characterized by the replacement with structurally normal tissue layers. These findings suggest that the high morbidity rate associated with esophagectomy procedures may be reduced by this ECM augmentation procedure at the anastomotic site.