Different mixtures of sodium hyaluronate and their ability to create submucosal fluid cushions for endoscopic mucosal resection

Endoscopic submucosal dissection for colorectal neoplasms: Risk factors for local recurrence and long-term surveillance

Objectives

Endoscopic submucosal dissection (ESD) is an effective procedure for the en bloc resection of colorectal neoplasms. However, risk factors for local recurrence after ESD have not been identified. This study aimed to evaluate such risk factors after ESD for colorectal neoplasms.

Methods

This retrospective study included 1344 patients with 1539 consecutive colorectal lesions who underwent ESD between September 2003 and December 2019. We investigated various factors associated with local recurrence in these patients. The main outcomes were the incidence of local recurrence and its relationship with clinicopathological factors during long-term surveillance.

Results

The en bloc resection rate was 98.6%, the R0 resection rate was 97.2%, and the histologically complete resection rate was 92.7%. Local recurrence was observed in 7/1344 (0.5%) patients and the median follow-up period was 72 months (range 4-195 months). The incidence of local recurrence was significantly higher in lesions ≥40 mm in diameter (hazard ratio [HR] 15.68 [1.88-130.5]; p = 0.011), piecemeal resection (HR 48.42 [10.7-218.7]; p < 0.001), non-R0 resection (HR 41.05 [9.025-186.7]; p < 0.001), histologically incomplete resection (HR 16.23 [3.627-72.63]; p<0.001), and severe fibrosis (F2; HR 9.523 [1.14-79.3]; p = 0.037).

Conclusions

Five risk factors for local recurrence after ESD were identified. Patients with such factors should undergo careful surveillance colonoscopy.

Electrosurgical knife with the water‐jet function of tip‐type during endoscopic treatment injection

Objectives

This study aimed to objectively evaluate the water‐jet‐functioned electrosurgical knife injection performances in a desktop experiment.

Methods

Five types of water‐jet‐functioned electrosurgical knives, including two injection styles of sheath‐type (A: DualKnife J, KD‐655L; B: FlushKnife, DK2620‐J‐B20S; C: Splash M‐Knife, DN‐D2718B; D: ISSEN, SN1650‐20) and tip‐type (E: ORISE ProKnife, M00519361) were evaluated. These knives were compared with an injection needle (Control: SuperGrip 25G) as a control. The injection speed under constant pressure and the injection efficiency for each knife against prepared porcine stomach mucosa were evaluated. The additional clear gel injections using an injection needle were observed using an indigo blue‐colored gel to evaluate the difference between the locations of water‐jet holes.

Results

Four types of knives, except for A, showed significantly higher water‐jet speeds (A: 0.79 ± 0.03 g/20 s, B: 2.56 ± 0.05 g/20 s, C: 3.09 ± 0.06 g/20 s, D: 2.86 ± 0.05 g/20 s, and E: 1.79 ± 0.03 g/20 s) compared to that of the control (1.21 ± 0.03 g/20 s). Meanwhile, significantly higher efficacy of injection was found in the tip‐type water‐jet function knife, second to the injection needle (Control: 37.2% ± 35.5%, A: 20.9% ± 20.2%, B: 1.1% ± 2.2%, C: 6.2% ± 12.6%, D: 12.5% ± 15.6%, and E: 33.3% ± 32.2%). An additional injection experiment revealed that the injection with a piercing tip into the gel could achieve sufficient additional injection inside the stacked clear gel.

Conclusions

The tip‐type water‐jet function electrosurgical knife is preferable for effective submucosal injection during endoscopic treatments.

Endoscopic submucosal dissection: How to be more efficient?

Endoscopic submucosal dissection (ESD) allows an "en bloc" resection with safety margins (R0 resection) regardless of the size of the lesion. However, while R0 brings a real benefit for the patient, it is not considered sufficient by many experts to justify the technical difficulties and the longer procedure time compared to piecemeal mucosectomy. The aims of this review are to provide several technical and strategical tips to help you save time and become comfortable during ESD procedures. ESD is divided into several intertwined phases: injection, incision, access to the submucosae, and submucosal dissection itself. During injection there are some mistakes that should not be made: a superficial injection, or on the contrary, a too deep injection. A good needle and good injection technique are mandatory. Some techniques, such as repeated injection or prolonged lifting solution, can help maintain the lift. After this step, mucosal incision can be made, taking care to have a good margin to allow an R0 resection. Starting the mucosal incision from a small point allows calibration of the depth of the incision and then obtaining a nice incision. Trimming is also very important to widen submucosal access. Then comes the submucosal dissection itself. Strategies such as the tunnel strategy or the pocket creation method can help to facilitate dissection, but more importantly, traction systems have become unavoidable, especially in the stomach and colon. Most common complications are bleeding and perforation, and they usually can be managed endoscopically.

Differences between two sodium hyaluronate-based submucosal injection materials currently used in Japan based on viscosity analysis

In Japan, two 0.4% sodium hyaluronate (HA)-based submucosal injection materials (SIMs) are currently used in endoscopic submucosal dissection (ESD): MucoUp (HA-Mc) and Ksmart (HA-Ks). HA-Mc and HA-Ks have the same concentration and are, thus, construed by most endoscopists to have no difference. Nevertheless, visual observation conveys the impression that HA-Ks have a higher viscosity than HA-Mc, suggesting that HA-Ks performs better than HA-Mc. This study aimed to examine the differences between HA-Mc and HA-Ks. HA-Ks exhibited higher viscosity due to greater weight-average molecular weight compared with HA-Mc. HA-Ks had significantly greater submucosal elevation height (SEH) than HA-Mc; the SEH of HA-Ks-80% (80% dilution of HA-Ks) was the same as that of HA-Mc. The ESD procedure time was significantly shorter with HA-Ks than with HA-Mc (15.2 ± 4.1 vs. 19.5 ± 5.9; P = 0.049). The total injection volume for HA-Ks was significantly lower than that for HA-Mc (10.8 ± 3.6 vs. 14.4 ± 4.6; P = 0.045). However, no significant difference in these items was observed between HA-Mc and HA-Ks-80%. HA-Mc and HA-Ks were considered to be almost the same. Nonetheless, HA-Ks exhibited higher viscosity and SIM performance than HA-Mc. HA-Ks-80% had almost the same performance as HA-Mc. Thus, understanding SIM performance and characteristics requires a focus on the viscosity of SIMs.

Efficacy and safety of a novel submucosal injection solution for endoscopic resection in porcine models

OBJECTIVE

A submucosal injection is usually required to improve the efficacy and safety of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR). This study aimed to evaluate the performance of 3.3% sodium carboxymethyl starch (Na-CMS) solution, a novel submucosal injection solution, for ESD and EMR.

METHODS

Na-CMS, normal saline (NS) and two commercially available agents (sigMAVisc and Eleview) were injected into the esophageal submucosa of randomly grouped pigs. The level of submucosal elevation was examined. Subsequently, ESD or EMR procedures using 3.3% Na-CMS or NS as submucosal injections were performed in the gastrointestinal tract of the pigs.

RESULTS

Submucosal elevation was significantly higher and more sustained in the 3.3% Na-CMS group than in the controls (P < 0.05). The volume required for ESD or EMR was significantly lower in the 3.3% Na-CMS group than in the NS group (ESD: 12.21 ± 4.09 mL vs 28.25 ± 8.02 mL, P < 0.001; EMR: 3.99 ± 1.98 mL vs 7.15 ± 3.67 mL, P = 0.001). The ESD resection time was significantly shorter in the 3.3% Na-CMS group than in the NS group (16.58 ± 7.30 min vs 25.29 ± 11.89 min, P = 0.004). Hemorrhage after ESD in the 3.3% Na-CMS group was less severe than that in the NS group (P = 0.006).

CONCLUSION

3.3% Na-CMS is an effective, safe and low-cost submucosal injection solution and holds promise as preferable agent for submucosal injection in ESD and EMR procedures.

Endoscopic mucosal resection vs endoscopic submucosal dissection for superficial non-ampullary duodenal tumors

BACKGROUND

The selection of endoscopic treatments for superficial non-ampullary duodenal epithelial tumors (SNADETs) is controversial.

AIM

To compare the efficacy and safety of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) for SNADETs.

METHODS

We retrospectively analyzed the data of patients with SNADETs from a database of endoscopic treatment for SNADETs, which included eight hospitals in Fukuoka, Japan, between April 2001 and October 2017. A total of 142 patients with SNADETs treated with EMR or ESD were analyzed. Propensity score matching was performed to adjust for the differences in the patient characteristics between the two groups. We analyzed the treatment outcomes, including the rates of en bloc/complete resection, procedure time, adverse event rate, hospital stay, and local or metastatic recurrence.

RESULTS

Twenty-eight pairs of patients were created. The characteristics of patients between the two groups were similar after matching. The EMR group had a significantly shorter procedure time and hospital stay than those of the ESD group [median procedure time (interquartile range): 6 (3-10.75) min vs 87.5 (68.5-136.5) min, P < 0.001, hospital stay: 8 (6-10.75) d vs 11 (8.25-14.75) d, P = 0.006]. Other outcomes were not significantly different between the two groups (en bloc resection rate: 82.1% vs 92.9%, P = 0.42; complete resection rate: 71.4% vs 89.3%, P = 0.18; and adverse event rate: 3.6% vs 17.9%, P = 0.19, local recurrence rate: 3.6% vs 0%, P = 1; metastatic recurrence rate: 0% in both). Only one patient in the ESD group underwent emergency surgery owing to intraoperative perforation.

CONCLUSION

EMR has significantly shorter procedure time and hospital stay than ESD, and provides acceptable curability and safety compared to ESD. Accordingly, EMR for SNADETs is associated with lower medical costs.

EMR/ESD: Techniques, Complications, and Evidence

PURPOSE OF REVIEW

To discuss endoscopic resection techniques of early gastrointestinal malignancy. The review will focus on the indications and outcomes of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD).

RECENT FINDINGS

EMR is indicated for upper GI lesions less than 20 mm provided they can be easily lifted and have a low risk of submucosal invasion (SMI). ESD should be considered for esophageal and gastric lesions that are bulky, show intramucosal carcinoma, or have a risk of superficial submucosal invasion. With regard to colonic polyps, EMR is acceptable for the removal of large colonic polyps using a piecemeal technique. ESD can be reserved for rectal neuroendocrine tumors, fibrotic polyps, or polyps harboring early malignancy. In selected cases, particularly in lesions less than 2 cm in size, EMR can be safe and effective. For larger lesions or lesions with submucosal invasion, ESD is effective and curative. Choosing the best approach can be tailored for each patient depending on lesion size, pathology, and availability of local expertise.

Review on colorectal endoscopic submucosal dissection focusing on the technical aspect

BACKGROUND

Endoscopic submucosal dissection (ESD) enables removal of broad-based colorectal polyps or lateral spreading tumors with a higher rate of en bloc resection and a lower risk of local recurrence. However, it is technically demanding. Over the past 20 years, various equipment and innovative techniques have been developed to reduce the difficulty of ESD. The information in the literature is scattered. Our aim is to provide a comprehensive review on the setup and technical aspects of colorectal ESD.

METHODS

We searched the PubMed database and systemically reviewed all original and review articles related to colorectal ESD. Further manual search according to reference lists of identified articles were done. The selected articles were categorized and reviewed. Original figures were created to help readers understand some of the ESD techniques.

RESULTS

A total of 216 articles were identified, in which 25 of them were review articles and 191 of them were original articles. They were categorized and reviewed. An in-depth appraisal of the setting, equipment, and technical aspects of colorectal ESD was performed.

CONCLUSIONS

Although ESD is a technically demanding procedure that requires expert endoscopic skills, it can be mastered. With good peri-procedural preparation, sufficient knowledge of the equipment, and thorough understanding of the useful endoscopic tricks and maneuvers, colorectal ESD can be performed smoothly and safely.

Short- and long-term outcomes of endoscopic submucosal dissection for early gastric cancer in the remnant stomach after gastrectomy

BACKGROUND

Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) in the remnant stomach is a minimally invasive treatment. Few studies compared the technical difficulty of ESD involving the suture line and anastomosis, and information on long-term outcomes is insufficient. This study aimed to elucidate the short- and long-term outcomes of ESD for EGC in the remnant stomach.

METHODS

We investigated patients who underwent ESD for EGC in the remnant stomach between September 2002 and March 2016. Clinicopathological data were retrieved to assess en bloc resection rates, complications, and long-term outcomes including overall survival and cause-specific survival.

RESULTS

A total of 136 consecutive patients with 165 lesions resected by 157 ESD procedures were retrospectively evaluated. The en bloc resection rate was 95.5%. Complications included 16 intraoperative perforations (10.2%), 2 delayed perforations (1.3%), and 15 delayed bleeding (9.6%), which were successfully treated with endoscopy. The en bloc resection rate was significantly higher in the suture line group (100%) and the non-anastomosis or suture line group (98.8%) than in the anastomosis group (82.9%). However, the intraoperative perforation rate was significantly higher in the anastomosis group (31.4%) than in other groups. The 5-year overall and cause-specific survival rates were 88.4% and 97.6%, respectively, during a median follow-up period of 50.7 months (interquartile range 30.8-91.3).

CONCLUSIONS

The long-term outcomes of ESD for EGC in the remnant stomach were favorable. However, ESD involving the anastomosis was a technically demanding procedure due to the low en bloc resection rate and high perforation rate.

Resection of Mucosal and Submucosal Gastrointestinal Lesions and a Double Endoscope Experience

Aim:

The patients who underwent endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) for mucosal and submucosal lesions of the esophagus, stomach, and duodenum and the advantages of the double endoscope method we used for traction during ESD were evaluated.

Material and Methods:

The patients who underwent ESD and EMR due to upper gastrointestinal lesions were evaluated retrospectively between January 2014 and April 2018 in our endoscopy unit.

Result:

The mean age of 10 patients with esophageal lesions was 53 years. ESD was performed for 7 lesions and EMR for 3 lesions. The most common lesion was leiomyoma and the median size of the lesions was 1.4 cm (range, 0.6–2.5 cm).

The median age of 26 patients with gastric lesions was 61 years. EMR were performed for 11 lesions and ESD for 15 lesions. Double endoscope was used in 6 patients. One patient had intramucosal carcinoma, while the other lesions were benign and dysplasia was the most common lesion. The median size of lesions was 1.8 cm (range, 1–3 cm).

All lesions were evaluated with endoscopic ultrasonography. Bleeding was seen in 4 patients and perforation in 1 patient during ESD and defect was closed with endoscopic clips.

Conclusion:

The advantages of endoscopic resections; short hospitalization, low complication rates, patient comfort, and doesn't require the general anesthesia. For endoscopic resection, we think that the second endoscope shortens the duration of the procedure, reduces the complication rate, and increases the comfort of the endoscopist.

Endoscopic submucosal dissection with a novel high viscosity injection solution (LiftUp) in an ex vivo model: a prospective randomized study

Introduction  Endoscopic submucosal dissection (ESD) is increasingly being used in the western world. Submucosal injectates are an essential tool for the ESD procedure. In this study, we evaluated a novel copolymer injectate (LiftUp, Ovesco, Tübingen Germany) in an established ESD model (EASIE-R) in comparison to existing submucosal injectables. Materials and methods  We conducted a prospective, randomized ex vivo study performing ESD with three injectates: LiftUp, hydroxyethyl starch (HAES 6 %) and normal saline solution (NaCl 0.9 %). A total of 60 artificial lesions, each 3 × 3 cm in size, were resected in an ex vivo porcine model, utilizing one of the three studied injectates (n = 20 ESDs per injectate). Study parameters were: en bloc resection rate, perforation rate, lifting property, time of injection, injectate volume, general ESD procedure time, and overall procedure time. Results  All 60 lesions were successfully resected using the standard ESD technique. LiftUp had no procedure related perforations, one perforation occurred in the HAES group, and two perforations in the NaCl group ( P  > 0.05). Furthermore, adequate lifting was achieved in 16/20 (80 %) using LiftUp, 6/20 (30 %) in the HAES group and 6/20 (30 %) in the NaCl group ( P  < 0.0002). En bloc resection was achieved in 19 (95 %) with LiftUp, in 20 (100 %) with HAES, and in 16 (80 %) with NaCl. General ESD procedure time and overall procedure time were not different among the three groups. Conclusion  LiftUp appears to be a safe alternative to established fluids for ESD. It had a significantly improved lifting effect and required significantly less injected volume compared to well-established lifting solutions.

Identification of the critical viscoelastic factor in the performance of submucosal injection materials

High-performance submucosal injection materials (SIMs) contribute to the success of endoscopic therapy for early-stage gastrointestinal neoplasms. This study aimed to identify the most important factor (viscoelastic parameter) that determines SIM performance and the ease of injection. To determine the ideal viscoelastic parameters of SIMs, submucosal elevation heights (SEHs) and the ease of submucosal injection [characterized by injection pressures (IPs)] were evaluated using a newly developed ex vivo model, in which a constant tension was applied to the studied specimen. The strongest positive correlation was observed between the loss modulus determined at an oscillation frequency of 0.1 rad/s and SEH (correlation coefficient > 0.9) and between the loss modulus at 10 rad/s and IP (correlation coefficient > 0.9). SIMs with high loss moduli (0.1 rad/s) also contributed to maintenance of the submucosal elevation. Moreover, the SEHs of pseudoplastic fluid SIMs (whose loss moduli increased slightly with increasing angular frequency) were greater than those of Newtonian fluid SIMs (whose loss modulus increased drastically with increasing angular frequency). In this study, the ideal viscoelastic SIM parameters were clarified. The loss modulus (0.1 rad/s) was the most important viscoelastic factor affecting SIM performance. Additionally, the development of pseudoplastic fluid SIMs may lead to the creation of next-generation SIMs, with a performance superior to that of sodium hyaluronate, which is currently used widely in endoscopic treatments.

Water-pocket endoscopic submucosal dissection for superficial gastric neoplasms (with video)

BACKGROUND AND AIMS

During endoscopic submucosal dissection (ESD), a clear view is essential for precise dissection of the appropriate submucosal layer. Some advantages have been reported for underwater techniques of endoscopic resection in comparison with the gas insufflation method. We have developed a new ESD method with the creation of a local water pocket (WP) that provides a clear view in the dissection field. Therefore, we aimed to investigate the feasibility and safety of WP-ESD for superficial gastric neoplasms.

METHODS

We prospectively recruited 50 patients with gastric neoplasms (early gastric cancer or gastric adenomas) between April 2017 and December 2017. Among them, 48 patients were treated with the WP-ESD technique. The patients undergoing WP-ESD were compared with 48 patients treated with standard ESD (S-ESD) who were selected by propensity score matching. The primary outcome was the ESD procedure time.

RESULTS

Total procedure time was significantly shorter in the WP-ESD group than in the S-ESD group (median [interquartile range], 27.5 [19-45] minutes vs 41 [29.8-69] minutes; P < .001). Similarly, the dissection speed was significantly greater in the WP-ESD group than in the S-ESD group (median [interquartile range], 22.5 [16.8-35.3] mm²/min vs 17.3 [12.7-22.1] mm²/min; P < .001). The rates of complete en bloc resection in the WP-ESD group and the S-ESD group were 97.9% and 95.8%, respectively (P > .99). There were no perforations in either group.

CONCLUSION

WP-ESD was associated with a shorter procedure time than S-ESD. WP-ESD may provide an alternative method for resection of superficial gastric neoplasms. (Clinical trial registration number: UMIN 000030266.).

Management and risk factor of stenosis after endoscopic submucosal dissection for colorectal neoplasms

BACKGROUND AND AIM

Although endoscopic submucosal dissection (ESD) enables en bloc removal of large colorectal neoplasms, the incidence of stenosis after ESD and its risk factors have not been well described. This study aimed to determine the risk factors of stenosis and verify the surveillance and treatment of stenosis.

METHODS

This retrospective study included 822 patients, with a total of 912 consecutive colorectal lesions, who underwent ESD from September 2003 to May 2015. The main outcome measures were incidence of stenosis and its relationship with the clinicopathologic factors in surveillance.

RESULTS

Surveillance endoscopy was performed 6 months after ESD. Four of the 822 patients (0.49%) developed stenosis and required unanticipated endoscopy. The other 908 cases in 818 patients showed no symptoms or only slight abdominal discomfort (that was controlled with medication) and did not require any dilation or steroid therapies. Post-ESD stenosis was observed in 11.1% (2/18) of patients with circumferential resection between ≥90% and <100% and in 50% (2/4) of patients with circumferential resection of 100%. Among the 50 cases with a circumferential mucosal defect ≥75%, a circumferential mucosal defect ≥90% was a significant risk factor (P = .005). Four patients with stenosis were treated successfully by endoscopic dilation.

CONCLUSIONS

Circumferential mucosal defect of more than 90% is a significant risk factor for stenosis after colorectal ESD. Surveillance endoscopy 6 months after ESD is recommended to assess for development of stenosis. Defects smaller than 90% do not require close endoscopic follow-up or prophylactic measures for prevention of post-ESD stenosis. (UMIN clinical trial registration number: UMIN000015754.).

Risk factors associated with difficult gastric endoscopic submucosal dissection: predicting difficult ESD

BACKGROUND AND STUDY AIM

Endoscopic submucosal dissection (ESD) is a widely accepted treatment for superficial gastric neoplasms. Difficult ESD can lead to complications, such as bleeding and perforation. To predict difficult ESD procedures, we analyzed the factors associated with difficult ESD.

PATIENTS AND METHODS

The medical records of 1052 ESD procedures were retrospectively reviewed. Difficult ESD was defined by any one of three end points: longer procedure time (≥60 min), piecemeal resection, incomplete (R1) resection, or gastric wall perforation. To determine the factors associated with difficult ESD, clinical and pathologic features and endoscopic findings were analyzed.

RESULTS

The rates of en bloc resection and curative (R0) resection were 93.3 and 92.4 %, respectively. The mean procedure time was 27.7 ± 16.7 min. After multivariate analysis, larger tumor size (≥20 mm) was an independent risk factor for longer procedure time (OR 4.1, P < 0.001), for piecemeal resection (OR 2.3, P = 0.003) and incomplete (R1) resection (OR 2.1, P = 0.005). Location of the lesion (upper third) was an independent risk factor for longer procedure time (OR 5.8, P < 0.001), for piecemeal resection (OR 4.1, P < 0.001) and incomplete (R1) resection (OR 4.5, P < 0.001). Submucosal fibrosis was an independent risk factor for longer procedure time (OR 9.7, P < 0.001), for piecemeal resection (OR 2.4, P < 0.001) and incomplete (R1) resection (OR 2.6, P < 0.001). Finally, submucosal invasive gastric cancer was an independent risk factor for piecemeal resection (OR 2.6, P = 0.008), for perforation (OR 19.3, P = 0.001) and for incomplete (R1) resection (OR 2.7, P = 0.001).

CONCLUSIONS

Difficult ESD procedures are a function of the lesion size and location, submucosal fibrosis, and submucosal invasive cancer. When a difficult ESD procedure is expected, appropriate preparations should be considered, including consultation with more experienced endoscopists.

A feasibility study of a thermally sensitive elastin-like polypeptide for submucosal injection application in endoscopic resection in 3 animal models

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) can successfully resect large lesions en bloc by using a submucosal injection solution, but the cost of currently available submucosal injection solutions is not satisfactory. The authors' aim was to evaluate the feasibility and effectiveness of a thermally sensitive elastin-like polypeptide (ELP) used as submucosal injection solution in ESD.

METHODS

We conducted an ex vivo study to determine the optimal concentration of ELPs in rabbits, an in vivo study to evaluate the effectiveness of mucosal elevation in rats, and a large animal study to confirm the feasibility of preclinical application by using conventional clinical procedure in pigs.

RESULTS

ELP (500 μM) was proved to be the optimal injectable submucosal injection solution and elevated mucosa more efficiently than any control. The same concentration of ELP exhibited an equivalent effectiveness of mucosal elevation, the retention of the elevation, and minimal bleeding with sodium hyaluronate. The ESD procedure time with 500 μM ELP in a preclinical study with pigs was significantly shorter than with any other concentration of ELP and normal saline solution.

CONCLUSIONS

Use of ELP as submucosal injection solution was feasible, with higher and longer-lasting elevation and fewer adverse events.

Usefulness of Ready-to-Use 0.4% Sodium Hyaluronate (Endo-Ease) in the Endoscopic Resection of Gastrointestinal Neoplasms

BACKGROUND/AIMS

Commercially available sodium hyaluronate solutions are usually too thick to inject through catheters and need dilution with normal saline (NS) before use, which increases the risk of contamination. We evaluated the usefulness of ready-to-use 0.4% sodium hyaluronate, Endo-Ease (EE; UNIMED Pharm. Inc., Seoul, Korea).

METHODS

We performed a prospective multicenter randomized study from May 2011 to September 2012. Patients requiring endoscopic resection (ER) for gastric or colorectal neoplasm at two referral hospitals were enrolled.

RESULTS

One hundred fifty-four patients (72 with a gastric neoplasm and 82 with a colorectal neoplasm) were included in intention-to-treat analysis. Thirty-seven gastric neoplasms and 43 colorectal neoplasms were enrolled in the EE group. The usefulness rate was significantly higher in the EE group than in the NS group (89.2% vs. 60.0% for gastric neoplasms and 95.3% vs. 67.7% for colorectal neoplasms, p<0.001). In the EE group, the ease of mucosal resection was significantly higher than in the NS group (p<0.001). The injected volume was smaller in the EE group than in the NS group (p<0.05).

CONCLUSIONS

The use of EE reduced the need for additional injections and improved the ease of ER. A submucosal injection of EE is useful for the ER of both gastric and colorectal neoplasms.

Improved Techniques for Endoscopic Mucosal Resection (EMR) in Colorectal Adenoma

Background

Endoscopic therapy of colorectal adenomas and early cancers is a standard method. Besides oncological criteria, the method is limited by polyp location, size, and texture.

Method

Based on the current literature, technical modifications and developments in endoscopic mucosal resection are described.

Results

Numerous approaches exist to improve the conditions of resection, including optimisation of mucosal elevation and modification of techniques, tools, and devices.

Conclusion

Endoscopic therapy of sessile and flat colorectal polyps remains a challenge. Some of the presented modifications can help to address this challenge.

Clinical characteristics and management of gastric tube cancer with endoscopic submucosal dissection

AIM: To identify the characteristics of gastric tube cancer (GTC) and the complications associated with endoscopic submucosal dissection (ESD) for GTC.

METHODS: Between 2007 and 2012, 11 individuals with early gastric cancer in the reconstructed gastric tube after esophagectomy who underwent ESD in this hospital were studied. The characteristics of GTC were identified, and the complications of ESD for GTC were analyzed at three phases: preoperative, intraoperative, and postoperative.

RESULTS: A total of 11 consecutive patients with 11 GTCs were selected for this study. All cases underwent en bloc resections by ESD. The median procedure time was 142 min. The average GTC diameter was 26.1 mm, and the average size of the resected lesions was 45.5 mm. The histopathological diagnosis in all cases was a differentiated adenocarcinoma. In the preoperative phase, anastomotic strictures (5/11, 45%) and food residues (4/11, 36.4%) in the gastric tube were the main complications. In the intraoperative phase, bleeding was observed in 5 cases (45%). The postoperative complications observed were delayed bleeding in 2 cases (18.2%) and stenosis in one case (9.1%). The case with stenosis was successfully treated using endoscopic balloon dilatation.

CONCLUSION: Minor complications were frequently observed. However, all GTCs underwent en bloc resection with ESD without any serious complications. ESD is considered a useful treatment for GTC.

Efficacy of endoscopic submucosal dissection for cancer of the operated stomach

PURPOSE

Cancer can develop in the operated stomach after partial gastrectomy and in the reconstructed gastric tube after surgery for esophageal cancer. It is considered that endoscopic therapy is more safe and suitable for the early gastric cancer developed in such stomach than operation. We investigated the efficacy of endoscopic submucosal dissection (ESD) for cancer of the operated stomach.

METHODS

Subjects were 669 gastric cancer patients who underwent ESD: 22 patients (23 lesions) had surgically altered gastric anatomy, whereas 647 patients (727 lesions) had normal gastric anatomy. In the altered gastric anatomy group, 13 patients, 6 patients, and 3 patients had previously undergone distal gastrectomy, gastric tube reconstruction, and proximal gastrectomy, respectively. Rates of complete en bloc resection and curative resection were compared between the two groups. Influence of an anastomotic site and/or a suture line on ESD outcomes was examined in the altered gastric anatomy group.

RESULTS

The rate of complete en bloc resection by ESD was 82.6% (19/23 lesions) in the altered gastric anatomy group and 92.3% (671/727 lesions) in the normal gastric anatomy group. The rate of curative resection and incident rates of complications were not significantly different between the groups. In the altered gastric anatomy group, the rate of complete en bloc resection was significantly lower when a lesion had spread across an anastomotic site and/or a suture line (P = 0.0372). Furthermore, duration of ESD was significantly longer (P = 0.0276), and resection efficiency was significantly lower (13 mm(2)/min, P = 0.0283), when treating lesions with an anastomotic site and/or a suture line than when treating isolated lesions.

CONCLUSIONS

Outcome of ESD for cancer of the operated stomach compares with that in normal stomach anatomy. Anastomotic site/suture line within a lesion influenced the ESD procedure.

Efficacy of endoscopic submucosal dissection for cancer of the operated stomach

PURPOSE

Cancer can develop in the operated stomach after partial gastrectomy and in the reconstructed gastric tube after surgery for esophageal cancer. It is considered that endoscopic therapy is more safe and suitable for the early gastric cancer developed in such stomach than operation. We investigated the efficacy of endoscopic submucosal dissection (ESD) for cancer of the operated stomach.

METHODS

Subjects were 669 gastric cancer patients who underwent ESD: 22 patients (23 lesions) had surgically altered gastric anatomy, whereas 647 patients (727 lesions) had normal gastric anatomy. In the altered gastric anatomy group, 13 patients, 6 patients, and 3 patients had previously undergone distal gastrectomy, gastric tube reconstruction, and proximal gastrectomy, respectively. Rates of complete en bloc resection and curative resection were compared between the two groups. Influence of an anastomotic site and/or a suture line on ESD outcomes was examined in the altered gastric anatomy group.

RESULTS

The rate of complete en bloc resection by ESD was 82.6% (19/23 lesions) in the altered gastric anatomy group and 92.3% (671/727 lesions) in the normal gastric anatomy group. The rate of curative resection and incident rates of complications were not significantly different between the groups. In the altered gastric anatomy group, the rate of complete en bloc resection was significantly lower when a lesion had spread across an anastomotic site and/or a suture line (P = 0.0372). Furthermore, duration of ESD was significantly longer (P = 0.0276), and resection efficiency was significantly lower (13 mm(2)/min, P = 0.0283), when treating lesions with an anastomotic site and/or a suture line than when treating isolated lesions.

CONCLUSIONS

Outcome of ESD for cancer of the operated stomach compares with that in normal stomach anatomy. Anastomotic site/suture line within a lesion influenced the ESD procedure.

Endoscopic submucosal dissection in the colorectum: Feasibility in the Canadian setting

Endoscopic submucosal dissection is a minimally invasive endoscopic technique for the removal of gastrointestinal tumours that is increasingly being used for colonic neoplasms to spare resection of colon in selected patients. Colonic endoscopic submucosal dissection is technically challenging and was initially pioneered in Japan but increasingly used in selected western centres. Its use in Canada is currently limited, and the authors review the challenges and opportunities, in addition to the unique training infrastructure required to practice the procedure under supervision. Specific tools are required to perform endoscopic submucosal dissection and meticulous attention to detail is essential. The authors provide a combined Japanese and Canadian perspective to this technique, and discuss training and performance of endoscopic submucosal dissection as well as potential indications.

Training methods and models for colonoscopic insertion, endoscopic mucosal resection, and endoscopic submucosal dissection

Colonoscopic examination is considered an effective examination for the detection of colorectal cancers. Additionally, early colorectal cancers can be resected using endoscopic techniques such as endoscopic mucosal resection and endoscopic submucosal dissection. However, those examinations and treatments need special techniques. Various training methods are practiced to acquire such endoscopic techniques throughout the world. In clinical cases, magnetic positioning devices help endoscopic insertion by less experienced endoscopists. There is a physical model made by polyvinyl chloride and a virtual simulator for training of colonoscopic insertion. Various techniques including a method to apply pressure to the abdomen and consideration for patient's pain can be trained using these models. In view of extensive training of endoscopic mucosal resection and endoscopic submucosal dissection, animal models are useful and actually used. Live animal models of minipig, which entails blood flow, are ideal and used frequently, but are cumbersome to prepare. On the other hand, ex vivo animal models using intestine of porcine and bovine are convenient for preparation and less expensive. Unique ex vivo animal models with blood flow have been developed recently and techniques for hemostasis can be practiced. With respect to a method of training for colorectal endoscopic submucosal dissection, a stepwise system has been adopted throughout the world. Thus, first they observe the expert's technique, then practice training of animal models, and finally, they perform clinical rectal cases. The system is useful for a safe and definite procedure. In this review, we reveal various training methods for colonoscopic examinations and treatments.

Evaluation of 0.6% sodium alginate as a submucosal injection material in endoscopic submucosal dissection for early gastric cancer

BACKGROUND AND AIM

We have focused on sodium alginate (SA) solution as a potential submucosal injection material for endoscopic submucosal dissection (ESD). A previous SA solution had high viscosity and problems such as difficult handling. After its properties were adjusted, SA solution was examined in vitro and its clinical safety was evaluated.

METHODS

With 0.4% sodium hyaluronate (SH) solution as a control, catheter injectability and mucosa-elevating capacity of 0.3-0.8% SA solutions were evaluated. Next, 0.6% SA solution was used for ESD in 10 patients with early gastric cancer in a prospective clinical study.

RESULTS

Compared with 0.4% SH solution, 0.6% SA solution exhibited no significant difference in catheter injectability but significant superiority in mucosa-elevating capacity. In the clinical study, no adverse events were observed in any patient.

CONCLUSION

The safety of 0.6% SA solution as a submucosal injection material was confirmed and it is suggested that its efficacy should be investigated in a larger number of cases.

Endoscopic Submucosal Dissection (ESD) in Colorectal Tumors

Background

Endoscopic submucosal dissection (ESD) – initially developed for the treatment of early gastric cancer in Japan – is an attractive option for en bloc resection of larger sessile or flat colorectal neoplasia.

Methods

A review of the current literature on colorectal ESD was carried out.

Results

In contrast to conventional endoscopic mucosal resection (EMR), ESD for larger colorectal neoplasia yields high en bloc resection rates and very low recurrence rates. The frequency of delayed bleeding is similar for EMR and ESD. Higher perforation rates during ESD are mostly due to microperforations identified and treated during the intervention, and are therefore of minor clinical relevance. A major disadvantage of ESD is the necessity for high-level endoscopic skills and long procedure times. ESD also has the potential to replace laparoscopic surgery or transanal endoscopic microsurgery mainly due to its lower complication rates.

Conclusion

ESD for the resection of larger flat or sessile colorectal lesions has potential advantages over conventional EMR or minimally invasive surgery. Due to the low incidence of early gastric cancer, experience with ESD will remain limited in Western countries. The spread of colorectal ESD will depend on adequate training opportunities and also on modifications yielding a reduction in procedure time.

Endoscopic submucosal dissection for gastric tube cancer after esophagectomy

BACKGROUND

Recent improvements in the survival of patients after esophagectomy have led to an increasing occurrence of gastric tube cancer (GTC). Removal of the reconstructed gastric tube, however, can lead to high morbidity and mortality.

OBJECTIVE

To assess the feasibility and effectiveness of endoscopic submucosal dissection (ESD) for GTC.

DESIGN

Retrospective study.

SETTING

National Cancer Center Hospital, Tokyo, Japan.

PATIENTS

We investigated patients with GTC after esophagectomy undergoing ESD from 1998 to 2011.

INTERVENTION ESD MAIN OUTCOME MEASUREMENTS

Patient characteristics, endoscopic findings, technical results, histopathology including curability and Helicobacter pylori gastritis, and long-term outcomes.

RESULTS

There were 51 consecutive patients with 79 lesions including 38 lesions (48%) meeting the absolute indication, 31 (39%) satisfying the expanded indications, and 10 (13%) falling outside such indications. The median procedure time was 90 minutes. There were 73 en bloc resections (92%), 59 en bloc resections with tumor-free margins (R0 resections, 75%), and 51 curative resections (65%) based on the Japanese Gastric Cancer Association criteria. Fifty patients (98%) were assessed as H pylori gastritis positive. Adverse events included 3 perforations (3.8%) during ESD and 2 delayed perforations (2.5%) without any emergency surgery and 3 delayed bleeding (3.8%). Local recurrence was detected in 4 patients (7.8%), and metachronous GTCs were identified in 18 patients (35%). Five patients (10%) died of GTC including 3 metachronous lesions. The 5-year overall survival rate was 68.4%, and the disease-specific survival rate was 86.7% with 100% for curative and 72.7% for non-curative patients during a median follow-up period of 3.8 years (range, 0-12.1 years).

LIMITATION

Single-center retrospective study.

CONCLUSIONS

ESD for GTC was feasible and effective for curative patients; however, long-term outcomes for non-curative patients were less satisfactory.

High-pressure jet injection of viscous solutions for endoscopic submucosal dissection: a study on ex vivo pig stomachs

BACKGROUND

Long-lasting lifting is a key factor during endoscopic submucosal dissection (ESD) and can be obtained by water-jet injection of saline solution or by injection of viscous macromolecular solutions. Combination of the jet injection and the macromolecular viscous solutions has never been used yet. We assessed the ability of a new water-jet system to inject viscous solutions in direct viewing and in retroflexion. We compared jet injection of saline solution and hyaluronate 0.5 % to perform ESD on ex vivo pig stomachs in order to evaluate the benefits of macromolecular solutions when injected by a jet-injector system.

METHODS

This is a prospective comparative study in pig stomachs. Using the jet injector, four viscous solutions were tested: hydroxyethyl starch, glycerol mix, hyaluronate sodic (0.5 %), and poloxamer mix. Ten ESDs larger than 25 mm (five in direct viewing and five in retroflexion) and one larger than 10 cm were performed with each solution. ESD with hyaluronate jet injection was then compared with ESD with saline jet injection by performing 50 ESDs in each group. A single, minimally-experienced operator conducted all the procedures.

RESULTS

All 145 resections were complete, including all marking points with two perforations. Eleven jet ESDs per solution were conducted without any injection issue. In the second part of the study, when compared with saline, significant benefit of hyaluronate was observed on dissection speed (0.80 vs. 1.08 cm(2)/min, p < 0.001).

CONCLUSION

This is the first report on a jet-injector system allowing injection of macromolecular viscous solutions even with retroflexed endoscope. Jet injection of macromolecular solutions can speed up dissection in comparison with saline, and should now be tested on humans.

Endoscopic submucosal dissection for superficial esophageal neoplasms using the stag beetle knife

Endoscopic submucosal dissection (ESD) is an accepted standard treatment for early gastric cancer but is not widely used in the esophagus because of technical difficulties. To increase the safety of esophageal ESD, we used a scissors-type device called the stag beetle (SB) knife. The aim of this study was to determine the efficacy and safety of ESD using the SB knife. We performed a single-center retrospective, uncontrolled trial. A total of 38 lesions were excised by ESD from 35 consecutive patients who were retrospectively divided into the following two groups according to the type of knife used to perform ESD: the hook knife (hook group) was used in 20 patients (21 lesions), and the SB knife (SB group) was used in 15 patients (17 lesions). We evaluated and compared the operative time, lesion size, en bloc resection rate, pathological margins free rate, and complication rate in both groups. The operative time was shorter in the SB group (median 70.0 minutes [interquartile range, 47.5-87.0]) than in the hook group (92.0 minutes [interquartile range, 63.0-114.0]) (P = 0.019), and the rate of complications in the SB group was 0% compared with 45.0% in the hook group (P = 0.004). However, the lesion size, en bloc resection rate, and pathological margins free rate did not differ significantly between the two groups. In conclusion, ESD using the SB knife was safer than that using a conventional knife for superficial esophageal neoplasms.

Colon polypectomy: a review of routine and advanced techniques

The value of performing comprehensive screening colonoscopy with complete colon polypectomy is widely accepted. Colon cancer is a significant cause of worldwide mortality and prospective studies have proven that colonoscopic polypectomy reduces both the incidence and mortality related to this disease. Over the past few decades the array of instruments and techniques have greatly expanded to assist with the safe endoscopic removal of colon polyps. This article will review the published literature regarding efficacy and safety of standard polypectomy techniques such as snare polypectomy, electrocautery, and endoscopic mucosal resection along with newer techniques such as endoscopic submucosal dissection and combined laparoscopic techniques.

Endoscopic resection for gastrointestinal neuroendocrine tumors

Gastrointestinal (GI) and neuroendocrine tumors (NETs) can be treated by mini-invasive endoscopic resection when localized in the superficial layers of the bowel wall and their size is <20 mm. Endoscopic diagnosis of NETs is usually incidental or suspected after clinical, laboratory or imaging findings. Endoscopic mucosal resection is the most commonly used technique for NET removal, endoscopic submucosal dissection is indicated in selected cases, while papillectomy is feasible for ampullary lesions. Histopathologic assessment of the resection margin (circumferential and deep) is important for staging. Incidence of endoscopic mucosal resection-/endoscopic submucosal dissection-related complications for removal of GI NETs are similar to those reported for other GI lesions. Endoscopic follow-up is based on histopathologic characteristics of the resected NETs and its site. NETs >20 mm in size, with penetration of the muscle layer and/or serosa are at high risk for metastases and surgical approach is recommended when feasible.

Endoscopic submucosal dissection for early gastric cancer in the remnant stomach after gastrectomy

BACKGROUND

Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) after surgical gastrectomy is a technically difficult procedure because of the limited working space in the remnant stomach as well as the presence of severe gastric fibrosis and staples under the suture line.

OBJECTIVE

We evaluated clinical results including long-term outcomes to determine the feasibility and effectiveness of ESD for EGC in the remnant stomach of patients after gastrectomy.

DESIGN

Retrospective study.

SETTING

National Cancer Center Hospital, Tokyo, Japan.

PATIENTS

We investigated patients undergoing ESD for EGC in the remnant stomach from 1997 to 2011.

INTERVENTION ESD MAIN OUTCOME MEASUREMENTS

We examined the patient characteristics, endoscopic findings, technical results, adverse events, and histopathologic results including curability and evaluations of Helicobacter pylori gastritis in addition to the rates of local recurrence, metachronous gastric cancer, overall survival, and cause-specific survival.

RESULTS

A total of 128 consecutive patients with 139 lesions had previously undergone 87 distal (68%), 25 proximal (19.5%) and 16 pylorus-preserving gastrectomies (12.5%). The median period from the original gastrectomy to the subsequent ESD for EGC in the remnant stomach was 5.7 years (range 0.6-51 years), the median tumor size was 13 mm (range 1-60 mm), and the median procedure time was 60 minutes (range 15-310 minutes). There were 131 en bloc resections (94%), with curative resections achieved for 109 lesions (78%); 22 lesions (16%) resulted in non-curative resections, and 8 lesions (6%) had only a horizontal margin positive or had inconclusive results. A total of 118 patients (92%) were assessed as H pylori gastritis-positive, with 7 patients (5%) negative. Adverse events included 2 cases of delayed bleeding (1.4%) and 2 perforations (1.4%), with 1 patient requiring emergency surgery. The 5-year overall and cause-specific survival rates were 87.3% and 100%, respectively, during a median follow-up period of 4.5 years (range 0-13.7 years), with no deaths from EGC in the remnant stomach.

LIMITATIONS

Single-center, retrospective study.

CONCLUSION

ESD for EGC in the remnant stomach of patients after gastrectomy was a feasible and effective therapeutic method and should become the standard treatment in such cases, based on the favorable long-term outcomes.

Alginate hydrogel as a potential alternative to hyaluronic acid as submucosal injection material

BACKGROUND

Sodium alginate is currently used in medical products, including drugs and cosmetic materials. It can also be used as a submucosal injection material due to its excellent water retention ability. Alginate with a high water retention ability is called alginate hydrogel (AH). The aim of this study was to investigate the usefulness of AH as a submucosal injection material.

METHODS

To investigate the optimal viscosity of AH as a submucosal injection material, we observed the changes in submucosal height from the initial submucosal height in the stomachs of six miniature pigs for each injection material tested (0.3 % AH, 0.5 % hyaluronic acid, glycerol). All submucosal heights were compared serially over time (3, 5, 10, 20, and 30 min). Both immediate and 1-week delayed tissue reactions were investigated endoscopically in the same living pigs. Histological analyses were performed after the animals had been sacrificed.

RESULTS

In a preliminary study, we determined that 0.3 % sodium alginate mixed with BaCl2 (400 μl) was the optimal viscosity of AH as an injection material. Our comparison of submucosal height changes over time showed that there was a significant decrease in submucosal height just 3 min following the injection of hyaluronic acid and glycerol, but that following the injection of AH a significant decrease in submucosal height was observed only after 10 min (p < 0.05). The histological analyses revealed that there were mild capillary dilations with congestion and mild fibrotic changes with some lymphocytic infiltration at the AH injection site.

CONCLUSION

Alginate hydrogel demonstrated long-lasting maintenance of submucosal elevation, safety, and cost-effectiveness in a pig model, which makes it a potential alternative to hyaluronic acid.

Efficacy and safety of 0.4 percent sodium hyaluronate for endoscopic submucosal dissection of gastric neoplasms

AIM: To evaluate the efficacy and safety of sodium hyaluronate solution (SH) in endoscopic submucosal dissection (ESD) of gastric neoplasms.

METHODS: A prospective multicenter randomized, double blind, controlled trial was designed and utilized in this study. A total of 76 patients with 5-20 mm sized gastric neoplasms were enrolled at three academic hospitals in South Korea from June 2011 to October 2011. Patients were randomly assigned to the 0.4% sodium hyaluronate or control groups. All lesions underwent endoscopic ESD. ESD was performed with 0.4%SH and normal saline (NS) solution for submucosal injection. Efficacy was assessed using en bloc resection and the number of additional injections. Secondary evaluation variables were the volume of injection material, steepness of mucosal elevation, bleeding rate, procedural time and operator satisfaction. Finally, the safety was assessed by analyzing adverse events during the study.

RESULTS: The usefulness rate in the 0.4%SH group and the controlled group had statistically significant difference under intention to treat (ITT) analysis (90.91% vs 61.11% P = 0.0041). Under per protocol (PP), the usefulness rate is statistically significant different (93.10% vs 61.76%, P = 0.0036). The difference in volume of the solution injected between 0.4%SH group and the controlled group and NS group was also statistically significant under intention to treat and per protocol analysis (ITT: 0.03 ± 0.02 mL vs 0.06 ± 0.03 mL, P = 0.0003, PP: 0.03 ± 0.02 mL vs 0.06 ± 0.03 mL, P = 0.0004). Satisfaction above the grade good was significantly higher in the SH group under intention to treat and per protocol analysis (ITT: 90.91% vs 61.11%, P = 0.0041, PP = 93.11% vs 61.77%, P = 0.0022). Adverse events above grade 3 were not noticed in either group. All adverse events were treated and were judged as not associated with the submucosal injection solutions.

CONCLUSION: 0.4%SH solution is a safe and effective agent that doesn’t cause any significant adverse events and is useful for submucosal injection during ESD.

Early gastric cancer and dysplasia

Since the concept of early gastric cancer was first described in Japan in 1962, its treatment has evolved from curative surgical resection to endoscopic resection, initially with polypectomy to more recently with endoscopic submucosal dissection. As worldwide experience with these endoscopic techniques evolve and gain acceptance, studies have confirmed its comparable effectiveness with historical surgical outcomes in carefully selected patients. The criteria for endoscopic resection have expanded to offer more patients improved quality of life, avoiding the morbidity and mortality associated with surgery. This article summarizes the evolutional role of endoscopic and surgical therapy in early gastric cancer.

Usefulness of sodium hyaluronate solution in colorectal endoscopic mucosal resection

BACKGROUND

In endoscopic mucosal resection (EMR), it is essential to inject submucosal fluid to prevent complications and ensure safe and complete en bloc resection of tumors. Sodium hyaluronate (SH) solution, which is effective in forming and maintaining a mucosal lift and is innocuous to mucosal tissue, is considered a useful injection solution for endoscopic submucosal dissection, a procedure associated with a high risk of perforation. This study was undertaken to assess the usefulness of this solution in EMR.

METHODS

Ninety-four patients with colorectal tumors of ≤20 mm in diameter were enrolled for this study and randomized to a SH solution group (0.2% two-fold diluted MucoUp) or to a normal saline group (control). Ease of EMR was primarily assessed based on ease of submucosal injection, ease of snaring and injection time.

RESULTS

SH solution was superior to normal saline for ease of submucosal injection (57 ± 0.7 vs 50 ± 0.7; P < 0.05), and it showed better results for ease of snaring with less variability (63 ± 0.8 vs 51 ± 1.0; P < 0.05). The mean injection time was similar between the two groups (3.0 ± 9.0 s and 3.0 ± 2.7 s, respectively). Post-procedural hemorrhage occurred in 7% patients (3/46) injected with SH solution and in 6% of patients (3/48) in the control group; there was no significant difference between the groups.

CONCLUSIONS

Use of two-fold diluted MucoUp facilitated colorectal EMR.

Difficult colon polypectomy

Colorectal cancer (CRC) is one of the leading causes of death from cancer in the world. We now know that 90% of CRC develop from adenomatous polyps. Polypectomy of colon adenomas leads to a significant reduction in the incidence of CRC. At present most of the polyps are removed endoscopically. The vast majority of colorectal polyps identified at colonoscopy are small and do not pose a significant challenge for resection to an appropriately trained and skilled endoscopist. Advanced polypectomy techniques are intended for the removal of difficult colon polyps. We have defined a “difficult polyp” as any lesion that due to its size, shape or location represents a challenge for the colonoscopist to remove. Although many “difficult polyps” will be an easy target for the advanced endoscopist, polyps that are larger than 15 mm, have a large pedicle, are flat and extended, are difficult to see or are located in the cecum or any angulated portion of the colon should be always considered difficult. Although very successful, advanced resection techniques can potentially cause serious, even life-threatening complications. Moreover, post polypectomy complications are more common in the presence of difficult polyps. Therefore, any endoscopist attempting advanced polypectomy techniques should be adequately supervised by an expert or have an excellent training in interventional endoscopy. This review describes several useful tips and tricks to deal with difficult polyps.

Learning curve for endoscopic submucosal dissection of early gastric cancer based on trainee experience

BACKGROUND AND AIM

There have been few previous reports on endoscopic submucosal dissection (ESD) learning curve for early gastric cancer (EGC) so we retrospectively assessed this subject based on experience of our trainees.

METHODS

Trainees in our center start performing ESDs for lesions in lower third of stomach with hands-on support by experts during first 10 cases and then perform ESDs by themselves primarily with verbal guidance from experts. They are gradually assigned to perform ESDs in middle and upper thirds of stomach. From January 1999 to December 2008, 464 EGC patients, who underwent ESD performed by 13 trainees, were assessed by dividing ESD cases into five training periods (A, 1-10; B, 11-20; C, 21-30; D, 31-40; and E, 41-50). We compared data from B to C, D and E.

RESULTS

Lesions in lower third were A/59%, B/57%, C/55%, D/36% and E/40% with B significantly higher than D (p<0.01) and E (p<0.05). Mean tumor sizes were A/13.9 ± 7.5mm, B/18.3 ± 11.4mm, C/19.0 ± 12.5mm, D/19.3 ± 11.7 mm and E/16.8 ± 10.3mm. En-bloc resection rate was 100% in every period. Delayed bleeding / perforation rates were A/0%/1.8%, B/2.8%/1.9%, C/1.9%/2.9%, D/1.1%/0% and E/2.1%/2.1%, respectively. Lower third procedure times were A/76 ± 39, B/90 ± 61, C/70 ± 48, D/60 ± 50 and E/55 ± 26 minutes with B significantly longer than D and E (p<0.05). Middle and upper third procedure times were A/104 ± 80, B/115 ± 68, C/106 ± 67, D/134 ± 86 and E/96 ± 55 minutes.

CONCLUSION

Step-by-step training was highly effective with 100% en-bloc resection rate and few complications. Learning curve point for our trainees to acquire performing ESD in lower third of stomach was 30 cases.

Efficacy of submucosal injection of different solutions inclusive blood components on mucosa elevation for endoscopic resection

Background

Endoscopic resection has become the standard treatment for noninvasive gastrointestinal malignancies. In flat mucosal tumors, normal saline is frequently used for submucosal fluid injection in order to reduce the risk of complications during endoscopic resection. Recent studies have demonstrated longer-lasting mucosa elevation by injection of agents such as hyaluronic acid or glyceol, rather than normal saline. We investigated the efficacy of different blood components in comparison with other solutions for use as a submucosal fluid cushion.

Methods

Normal saline, sodium hyaluronate, glyceol, hydroxyethyl starch, serum, plasma, and whole blood were evaluated for their effectiveness in creating a submucosal cushion. One milliliter of each solution was injected into the submucosa of 5 × 5 cm specimens of resected porcine stomach. Mucosa elevation was measured before and up to 60 minutes after injection.

Results

The shortest duration of mucosa elevation was observed after injection of normal saline, glyceol, and 0.125% hyaluronic acid. A significantly longer duration was obtained after injection of hydroxyethyl starch, 0.25% and 0.5% hyaluronic acid, serum, and plasma. However, whole blood generated a longer-lasting mucosa elevation than all other agents.

Conclusion

The results of the current study suggest that whole blood is more effective in generating long-lasting mucosa elevation than any other commonly used solution. Because autologous blood is readily available at almost no cost, this seems to be an optimal agent for creating the mucosa elevation needed for endoscopic resection. Further in vivo studies in humans are needed to clarify the potential role of autologous blood for long-lasting endoscopic mucosa resection or endoscopic submucosal dissection.

Endoscopic submucosal dissection is an effective and safe therapy for early gastric neoplasms: a multicenter feasible study

BACKGROUND AND AIM

The technique of endoscopic submucosal dissection (ESD) was introduced to obtain en bloc specimens of large early gastrointestinal neoplasms. The drawback of ESD is its technical difficulty and, consequently, its higher rate of complication. In this multicenter study, we investigated the therapeutic outcomes of ESD in consecutive patients.

METHODS

From January 2002 to December 2008, 485 early gastric neoplasms in 418 patients were consecutively treated by using ESD procedure performed by 6 endoscopists in 4 institutions in Tokyo. Demorgraphics, tumor location, therapeutic outcomes, and complication rates were analyzed.

RESULTS

The rates of en bloc resection, complete en bloc resection, submucosal invasion, and piecemeal resection were 93.6%, 85.4%, 10.9%, and 5.4%, respectively. In multivariate analysis, the en bloc resection rate was independently lower in lesions in upper portion than in lower portion (P<0.01), lower in larger lesions (>30 mm, P<0.05; 20 to 30 mm, P<0.05), and lower in lesions with a scar (P<0.01). Delayed bleeding occurrence was independently high in larger lesions (>30 mm, P<0.01; 20 to 29 mm, P<0.01) than in small lesions (<20 mm). Institution and endoscopists were not risk factors of en bloc resection and complications

CONCLUSIONS

ESD is an effective and safe therapy in the management of early gastric neoplasms when performed by well-trained endoscopists. Endoscopists should recognize the difficulty to perform ESD for en bloc resection of upper lesion, and the risk of delayed bleeding in cases of lesions >2 cm in size.

Sodium alginate as an ideal submucosal injection material for endoscopic submucosal resection: preliminary experimental and clinical study

BACKGROUND

Sodium alginate is used clinically in the treatment of peptic ulcer disease. Because of its viscosity, sodium alginate could possibly become a new submucosal injection material for use in endoscopic resection.

OBJECTIVE

We evaluated the feasibility of endoscopic submucosal dissection (ESD) using sodium alginate.

SETTING AND INTERVENTIONS

The lesion-lifting properties of sodium alginate were examined in porcine stomachs and were compared with those of normal saline solution and sodium hyaluronate solution. After confirming the proper concentration of sodium alginate, ESD using sodium alginate was performed in 11 patients with gastric mucosal cancer or adenoma.

MAIN OUTCOME MEASUREMENT

The lesion-lifting properties of sodium alginate and clinical outcomes were assessed.

RESULTS

The thickness of the submucosal elevation created by 3% sodium alginate in porcine stomach was equivalent to that of sodium hyaluronate. ESD using sodium alginate was completed successfully in all patients without adverse effects except in 1 patient in whom transient shrinkage of the gastric wall disappeared spontaneously after approximately 30 minutes. The mean tumor size was 15.3 mm. En bloc resection and a negative resection margin were obtained in all. Histopathologic examination revealed that all tumors were confined to the mucosal layer except for 1 that was confined to the submucosal layer without lymphovascular invasion, and there were no adverse effects such as tissue damage. No patient required additional treatment, and none showed recurrence during a median follow-up period of 28 months.

LIMITATIONS

Small sample size.

CONCLUSION

This preliminary study suggests that sodium alginate might be a novel, safe submucosal injection material for use in endoscopic resection. Further investigation of the properties of sodium alginate is warranted.

Efficacy of hyaluronic acid in endoscopic mucosal resection of colorectal tumors

BACKGROUND AND AIM

Endoscopic mucosal resection (EMR) is the standard procedure for colorectal tumors. High mucosal elevation by submucosal injection is important for definite en bloc resection and the prevention of perforation. Hyaluronic acid (HA) is a reportedly useful injection solution for high and long-lasting mucosal elevation, but the ideal HA concentration for optimization of mucosal elevation maintenance, injection pressure, and cost is unknown. In the present study, we assessed the appropriate concentration of HA for EMR.

METHODS

A resected porcine colon and esophagus were used. The injection solutions examined were 0.9% normal saline (NS) and four concentrations of an 800-KDa HA preparation (0.4%, 0.2%, 0.13%, and 0.1%). Each solution (2 mL) was injected into the submucosa; injection pressure was calculated, and elevation was measured. The durations of mucosal elevation and EMR were additionally assessed in the living minipig colon.

RESULTS

In the resected porcine colon, the mucosal elevation was measured 0, 2, 4, and 6 min after the submucosal injection. All concentrations of HA solution maintained greater mucosal elevation at all times than NS (P < 0.05). An almost similar result was obtained in the resected porcine esophagus. The injection pressure correlated with the HA concentration. In the living minipig colon, mucosal elevation diminished 2 min after the submucosal injection with NS, but was maintained 2 min after injection with 0.4%, 0.2%, and 0.13% HA. The average duration of EMR was 139 s.

CONCLUSIONS

Mucosal elevation by HA was greater than that by NS in resected and living animal models. We recommend 0.13% HA for maintaining mucosal elevation, injection pressure, and cost.

Carbon dioxide submucosal injection cushion: an innovative technique in endoscopic submucosal dissection

AIM

Endoscopic submucosal dissection (ESD) can successfully resect large lesions en bloc, but it requires a satisfactory submucosal (sm) injection agent for proper safety and efficacy. The aim of the present study was to evaluate the effectiveness of carbon dioxide (CO(2) ) as an ESD sm injection agent.

METHODS

In vitro study using porcine stomachs compared CO(2) with normal saline (NS) and sodium hyaluronic acid (SHA) solution, both of which are currently used to provide long-lasting sm elevation during ESD. Histopathological examination assessed differences between CO(2) and NS sm cushions. ESD were then carried out in vivo in the stomach and rectum of a live pig using CO(2) sm injection.

RESULTS

CO(2) sm elevation was significantly longer lasting than either NS or SHA (P<0.001). Histopathology revealed no mucosal layer tissue damage, and dissection of honeycomb-like fibrous connective tissue in the CO(2) sm cushion. Creating and maintaining a CO(2) sm cushion of sufficient elevation combined with partial physical dissection of the sm layer was achieved, followed by complete endoscopic dissection of the sm layer with all ESD, resulting in successful en-bloc resections having a mean specimen size of 24.3mm within 15min.

CONCLUSION

Safety and efficacy of CO(2) as a satisfactory sm injection agent during ESD was successfully demonstrated in these preliminary studies, warranting further investigation of this innovative technique.

Submucosal injection of 0.4% hydroxypropyl methylcellulose facilitates endoscopic mucosal resection of early gastrointestinal tumors

BACKGROUND AND AIMS

Submucosal injection of a viscoelastic solution prolongs submucosal lift, thus, facilitating endoscopic mucosal resection. Our objective was to assess the safety and clinical effectiveness of 0.4% hydroxypropyl methylcellulose (HPMC) as a submucosal injectant for endoscopic mucosal resection.

PATIENTS AND METHODS

A prospective, open-label, multicenter, phase 2 study was conducted at 2 academic institutions in Brazil. Eligible participants included patients with early gastrointestinal tumors larger than 10 mm. Outcomes evaluated included complete resection rates, volume of HPMC injected, duration of the submucosal cushion as assessed visually, histology of the resected leisons, and complication rates.

RESULTS

Over a 12-month period, 36 eligible patients with superficial neoplastic lesions (stomach 14, colon 11, rectum 5, esophagus 3, duodenum 3) were prospectively enrolled in the study. The mean size of the resected specimen was 20.4 mm (10 to 60 mm). The mean volume of 0.4% HPMC injected was 10.7 mL (range 4 to 35 mL). The mean duration of the submucosal fluid cushion was 27 minutes (range 9 to 70 min). Complete resection was successfully completed in 89%. Five patients (14%) developed immediate bleeding requiring endoclip and APC application. Esophageal perforation occurred in 1 patient requiring surgical intervention. There were no local or systemic adverse events related to HPMC use over the follow-up period (mean 2.2 mo).

CONCLUSION

HPMC solution (0.4%) provides an effective submucosal fluid cushion and is safe for endoscopic resection of early gastrointestinal neoplastic lesions.