Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion

Electrosurgical unit in GI endoscopy: the proper settings for practice

INTRODUCTION

Electrosurgical unit (ESU) is integral to the endoscopy unit. The proper knowledge of the Mode with setting is essential for good therapeutic outcomes and the safety of the patients.

AREAS COVERED

ESU generates high-frequency electric current, which could perform cutting and coagulation for various therapeutic interventions. We review the proper settings for common endoscopic interventions like hemostasis, polypectomy, sphincterotomy, and advanced procedures like endoscopic ultrasound-guided cysto-gastrostomy, bile duct drainage, and endoscopic Ampullectomy. We review the various waveforms of ESU in practice in endoscopy, including special conditions like patients with pacemakers.

EXPERT OPINION

Knowledge of the waveforms' duty cycle and crest factor is necessary. A high-duty cycle and lower crest factor lead to a good cutting effect on the tissue. Endocut is the most commonly used Mode in ESU in endoscopic practices like sphincterotomy and polypectomy. Endocut I mode (effect 1-2, duration 3, interval 3) is used for endoscopic sphincterotomy, while Forced Coag mode (Effect 2, 60 W) controls post-sphincterotomy bleeding. Endocut Q mode (Effect 2-3, duration 1, interval 3) is used for cutting the polyp, while Forced Coag mode (Effect 2, 60 W) is used before cutting for pre-coagulation of the stalk.

Endoscopic Submucosal Dissection for Esophageal Cancer: Current and Future

Endoscopic submucosal dissection (ESD) has been widely used to treat superficial esophageal cancer. The advantages of esophageal ESD include a high en bloc resection rate and accurate pathological diagnosis. It enables local resection of the primary tumor and accurate identification of the risk factors for lymph node metastasis, including depth, vascular invasion, and types of invasion. Even in cases with clinical T1b-SM cancer, ESD and additional treatment can achieve radical cure, depending on the risk of lymph node metastasis. Esophageal ESD will be increasingly vital in minimally invasive and effective esophageal cancer treatment. This article describes the current status and prospects of esophageal ESD.

Long-term Outcomes of Additional Endoscopic Treatments for Patients with Positive Lateral Margins after Endoscopic Submucosal Dissection for Early Gastric Cancer

Background/Aims

It is uncertain whether additional endoscopic treatment may be chosen over surgery in patients with positive lateral margins (pLMs) as the only non-curative factor after endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). We aimed to compare the long-term outcomes of additional endoscopic treatments in such patients with those of surgery and elucidate the clinicopathological factors that could influence the treatment selection.

Methods

A total of 99 patients with 101 EGC lesions undergoing additional treatment after non-curative ESD with pLMs as the only non-curative factor were analyzed. Among them, 25 (27 lesions) underwent ESD, 29 (29 lesions) underwent argon plasma coagulation (APC), and 45 (45 lesions) underwent surgery. Clinicopathological characteristics and long-term outcomes were compared.

Results

Residual tumor was found in 73.6% of cases. The presence of multiple pLMs was associated with higher risk of residual tumor (p=0.046). During a median follow-up of 58.9 months, recurrent or residual lesions after additional ESD and APC were found in 4% (1/25) and 6.8% (2/29) of patients, respectively. However, all were completely cured with surgery or repeated ESD. There were no extragastric recurrences after additional endoscopic treatment. Lymph node metastasis was identified after additional surgery in one (2.2%) patient with an EGC showing histological heterogeneity.

Conclusions

Given the favorable long-term outcomes, additional ESD or APC may be an acceptable choice for patients with pLMs as the only non-curative factor after ESD for EGC. However, clincopathological characteristics such as multiple pLMs and histological heterogeneity should be considered in the treatment selection.

Effect of Antithrombotic Therapy on Bleeding after Argon Plasma Coagulation for Gastric Neoplasms

Background/Aims

Postprocedural bleeding is known to be relatively low after argon plasma coagulation (APC) for gastric neoplasms; however, there are few studies proving the effect of antithrombotic agents. This study aimed to analyze the incidence of delayed bleeding (DB) based on antithrombotic agents administered and to identify the risk factors for DB in APC for gastric tumors.

Methods

A total of 785 patients with 824 lesions underwent APC for single gastric neoplasm between January 2011 and January 2018. After exclusion, 719 and 102 lesions were classified as belonging to the non-antithrombotics (non-AT) and AT groups, respectively. The clinical outcomes were compared between the two groups, and we determined the risk factors for DB in gastric APC.

Results

Of the total 821 cases, DB occurred in 20 cases (2.4%) 17 cases in the non-AT group and three cases in the AT group (2.4% vs 2.9%, p=0.728). Multivariate analysis of the risk factors for DB confirmed the following significant, independent risk factors male sex (odds ratio, 7.66; 95% confidence interval, 1.02 to 57.69; p=0.048) and chronic kidney disease (odds ratio, 4.51; 95% confidence interval, 1.57 to 13.02; p=0.005). Thromboembolic events and perforation were not observed in all patients regardless of whether they took AT agents.

Conclusions

AT therapy is acceptably safe in gastric APC because it does not significantly increase the incidence of DB. However, patients with chronic kidney disease or male sex need to receive careful follow-up on the incidence of post-APC bleeding.

Feasibility and effectiveness of endoscopic irreversible electroporation for the upper gastrointestinal tract: an experimental animal study

Irreversible electroporation (IRE) is a local non-thermal ablative technique currently used to treat solid tumors. Here, we investigated the clinical potency and safety of IRE with an endoscope in the upper gastrointestinal tract. Pigs were electroporated with recently designed endoscopic IRE catheters in the esophagus, stomach, and duodenum. Two successive strategies were introduced to optimize the electrical energy for the digestive tract. First, each organ was electroporated and the energy upscaled to confirm the upper limit energy inducing improper tissue results, including bleeding and perforation. Excluding the unacceptable energy from the first step, consecutive electroporations were performed with stepwise reductions in energy to identify the energy that damaged each layer. Inceptive research into inappropriate electrical intensity contributed to extensive hemorrhage and bowel perforation for each tissue above a certain energy threshold. However, experiments performed below the precluded energy accompanying hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays showed that damaged mucosal area and depth significantly decreased with decreased energy. Relevant histopathology showed infiltration of inflammatory cells with pyknotic nuclei at the electroporated lesion. This investigation demonstrated the possibility of endoscopic IRE in mucosal dysplasia or early malignant tumors of the hollow viscus.

Usefulness of argon plasma coagulation for superficial esophageal squamous cell neoplasia in patients at high risk or with limited endoscopic resectability

BACKGROUND/AIMS

Endoscopic resection is the standard treatment for superficial esophageal squamous-cell neoplasia (SESCN). However, we encounter patients in whom endoscopic resection is difficult to perform. We retrospectively studied the usefulness of argon plasma coagulation (APC) in patients with SESCN.

MATERIALS AND METHODS

The study comprised 45 patients with SESCN (81 lesions) who underwent APC in our hospital from March 1999 through August 2016. Clinicopathological characteristics, treatment time, the presence or absence of metastasis and recurrence, adverse events, and outcomes were studied.

RESULTS

The median follow-up was 40 months. The median age was 70 years. The tumor diameter was 10 mm or longer in 48 lesions and less than 10 mm in 33 lesions. The median treatment time was 22 minutes. The reasons for selecting APC were as follows: technical difficulty caused by the presence of metachronous multiple lesions in the radiation field after chemoradiotherapy or close proximity to the ulcer scar remaining after endoscopic treatment in 49 lesions (60.4%), and the presence of underlying diseases in 26 lesions (32.0%). Adverse events occurred in 2 patients (4.4%) who had hypoxemia due to over-sedation. Two lesions (2.5%) recurred locally but could be locally controlled by additional APC. No patient had metastasis or recurrence or died of esophageal neoplasia. The 3-year overall survival rate was 87.0%, and the 3-year recurrence-free survival rate was 97.2%.

CONCLUSION

APC can be a useful treatment option for SESCN in patients with a limited life expectancy, poor performance status, or technical difficulty in resection of superficial neoplasms.

Argon plasma coagulation for successful treatment of bile leakage after subtotal cholecystectomy

Background

Subtotal cholecystectomy is an effective surgical method to decrease the risk of complications for gallbladders that are difficult to remove. However, there is a risk for postoperative refractory bile leakage through the gallbladder stump. Here, we report a new management technique involving the use of argon plasma coagulation (APC) to stop bile leakage after a subtotal cholecystectomy.

Case presentation

A 74-year-old man was referred to our hospital for abdominal pain and fever. Contrast-enhanced computed tomography of the abdomen showed fluid collection, such as an abscess, surrounding the gallbladder and hepatic flexure colon. The patient was diagnosed with colonic perforative peritonitis, and he underwent emergency surgery. On laparotomy, the abscess was observed outside of the hepatic flexure colon and gallbladder necrosis was detected. The neck of the gallbladder and the area close to the hepatoduodenal ligament was severely inflamed prohibiting dissection. The hepatic flexure colon was part of the abscess wall, and resection was needed. A subtotal cholecystectomy and right hemicolectomy confirmed peritonitis caused by cholecystic perforation. The mucous membrane of the gallbladder neck that remained was necrotic or detached. Therefore, the stump of the gallbladder was closed by primary sutures without cauterization of the mucosa. On postoperative day 6, bile leakage from the gallbladder stump was revealed. Percutaneous and endoscopic retrograde cholangiography drainage were performed. However, the liquid, which seemed to be secreted from the mucosa of the remnant gallbladder, was continuously obtained. We used APC to cauterize the gallbladder mucosa through the fistula of the abdominal drainage tube. Bile leakage and mucus discharge were improved after three rounds of APC cauterization.

Conclusions

APC effectively treated refractory bile leakage from a gallbladder stump after subtotal cholecystectomy for severe cholecystitis.

Gastric mucosal devitalization (GMD): translation to a novel endoscopic metabolic therapy

Background and study aims  The metabolic effects of bariatric surgery may partially result from removal of the gastric mucosa, an often underappreciated endocrine organ. Using argon plasma coagulation (APC), we may be able to selectively devitalize (ablate) the mucosa. The aim of this study was to identify the optimal tissue color that would correspond to selective gastric mucosal devitalization (GMD) using ex-vivo human stomach specimens. Patients and methods  Stomach specimens were obtained at sleeve gastrectomy. Prior to APC application, a submucosal fluid cushion was created. APC was then applied over a 2 × 2-cm area to the fundus and body, aiming for the three indicator colors (white, golden, brown). Pathological analysis was then performed independently and in a blinded fashion by two pathologists to determine the depth of mucosal and submucosal percent thermal injury and mucosal percent cell death. Results  Six patients were enrolled. There was a significant correlation between tissue color and mucosal percent thermal injury. The highest percent mucosal thermal injury was seen with brown (99.6 %, 95 % CI: 98.7, 100), followed by golden (92.5 %, 95 % CI: 85.5, 99.5), and then white (75.2 %, 95 % CI: 58.3, 92.1, P  < 0.01). Submucosal thermal injury was seen in 88.9 % of the slides. Greater than minimal submucosal injury (> 10 % depth) was found significantly more with brown tissue color (91.6 %) than golden (75 %) or white (33.3 %, P  < 0.05). However, 91.7 % of the entire sample set < 50 % injury. Conclusion  GMD is achievable using APC without thermal injury to muscularis propria. A golden color results in sufficient mucosal injury with only superficial injury to the submucosa.

Clinical outcomes of endoscopic treatment for gastric epithelial neoplasm in remnant stomach after distal gastrectomy

BACKGROUNDS/AIM

We aimed to evaluate the feasibility of endoscopic treatment for gastric epithelial neoplasm in the remnant stomach after distal gastrectomy and compared the clinical outcomes by tumor location and endoscopic treatment modality.

METHODS

We reviewed the data of patients who underwent endoscopic treatment for gastric epithelial neoplasms in the remnant stomach after distal gastrectomy between January 1996 and August 2013. The treatments included endoscopic resection or argon plasma coagulation.

RESULTS

Herein, 107 patients (median age, 65.1 years; 92 men) encompassing 117 cases of gastric neoplasms in the remnant stomach after distal gastrectomy were endoscopically treated. Forty of these lesions were located at anastomotic sites; they were treated with endoscopic resection in 29 cases (72.5%) and argon plasma coagulation in 11 cases (27.5%). For 77 lesions located on the non-anastomotic site, endoscopic resection was performed in 68 cases (88.4%) and argon plasma coagulation was performed in nine cases (11.7%; p = 0.031). The mean endoscopic resection duration was significantly longer in the anastomotic site group than in the non-anastomotic site group (43.6 vs. 26.3 min, p = 0.018). Recurrence was observed in five (12.8%) patients in the former and in one (1.3%) in the latter (p = 0.015); all the patients were successfully retreated with endoscopic resection or APC.

CONCLUSIONS

Endoscopic treatment for gastric epithelial neoplasm in a remnant stomach after distal gastrectomy is effective and safe. However, closely monitoring for recurrence should be conducted, particularly when the tumor is located at the anastomotic site.

Cost-effectiveness and short-term clinical outcomes of argon plasma coagulation compared with endoscopic submucosal dissection in the treatment of gastric low-grade dysplasia

Endoscopic treatment such as endoscopic submucosal dissection (ESD) or argon plasma coagulation (APC) is widely performed to treat gastric low-grade dysplasia (LGD). We aimed to evaluate the clinical efficacy of APC versus ESD for gastric LGD in terms of cost-effectiveness. This was a retrospective review of patients with gastric LGD who were treated with endoscopic intervention (APC or ESD) between March 2011 to December 2015. Fifty-nine patients treated with APC and 124 patients treated with ESD were included. Patients in the APC group were significantly older (mean age, 67.68 vs 63.90 years, respectively, P < .01), had an increased rate of Helicobacter pylori infection (27.1 vs 10.5%, respectively, P < .01), and had a higher mean Charlson Comorbidity Index score (2.32 vs 0.38, respectively, P < .01) than those in the ESD group. The 2 groups did not differ in tumor size, location, macroscopic morphology, or surface configuration. The procedure time (11.31 vs56.44 minutes, respectively, P < .01), and hospital stay (3.2 vs 5.6 days, respectively, P < .01) were significantly, shorter in the APC group than in the ESD group. Additionally, the cost incurred was significantly, lower in the APC group than in the ESD group (962.03 vs 2,534.80 dollars, respectively, P < .01). APC has many advantages related to safety, and cost-effectiveness compared with ESD. Therefore, APC can be considered an alternative treatment option for gastric LGD.

The Usefulness of Argon Plasma Coagulation Compared with Endoscopic Submucosal Dissection to Treat Gastric Adenoma

Background/Aims

To date, the best therapeutic modality for gastric adenoma, especially low-grade adenoma, has not been established. The aim of this study was to assess the usefulness of argon plasma coagulation (APC) in treating gastric adenoma compared with endoscopic submucosal dissection (ESD).

Methods

We included 210 patients with gastric adenoma, who underwent treatment with either APC (97 patients) or ESD (113 patients). The clinical and pathologic characteristics, mean duration of hospital stay, complications, and recurrence rates between the two groups were compared.

Results

The mean adenoma size was 0.9 cm and 1.1 cm in the APC group and ESD group, respectively (p<0.001). The mean duration of hospital stay was significantly shorter in the APC group than in the ESD group (1.6 days vs. 5.8 days, p<0.001). Complications did not occur in the APC group. However, one case of perforation (0.9%) and 6 cases of bleeding (5.3%) occurred in the ESD group. The recurrence rates were 15.3% (15/97 patients) in the APC group and 3.5% (4/113 patients) in the ESD group (p=0.003). The proportion of hospitalization was less in the APC group (43.3%, 42/97) than in the ESD group (100.0%, 113/113) (p<0.001). Medical expense was less in the APC group (377,172 won) than in the ESD group (1,430,610 won) (p<0.001).

Conclusions

The findings of this study suggest that APC is a safe treatment method for gastric adenoma without serious complications. However, regular endoscopic follow-up is necessary to detect any residual or recurrent lesions due to the relatively high rate of local recurrence after APC.

Effects of Nd:YAG laser for the controlled and localized treatment of early gastrointestinal tumors: Preliminary in vivo study

Endoscopic submucosal dissection (ESD) is a minimally invasive technique allowing for the removal of early gastrointestinal (GI) tumors, widely considered as a valid alternative to conventional surgery. However, ESD is technically demanding, and potentially severe complications, such as bleeding and perforation, may occur. Energy-based techniques (e.g., radiofrequency ablation) might offer a potential alternative to ESD. However, their use mandates the ability to predict the damage induced and to identify a "signature" of the complete ablation, without the need for a physical specimen. Ideally, an energy-based procedure should be tunable in order to limit the ablation to the superficial layers, namely mucosa (M) and submucosa (SM), without injuring the muscularis propria (MP), thereby minimizing GI perforation. This experimental study aims to investigate thermal damage induced by Nd:YAG laser on the gastric wall, at different laser settings such as power (P) and time (t). Laser ablation was performed on the stomach wall of 6 Wistar rats. Two powers (2.5W and 1.0W) and 3 exposure times (12s, 6s and 2s) were tested, for a total of 30 ablations. Histological analysis allowed to assess thermal damage, in terms of damage depth (DD) and identification of involved layers. The ratio (R) between DD and the total depth (TD) of target layers (M+SM) was used as an index to evaluate the effectiveness of laser settings. At P=2.5W, MP was damaged (R>1) in the majority of cases (11/15). At P=1.0W, MP was preserved in all tests (R<;1), and rarely (4/15) did the damage reach the whole SM (R=1). Histopathological analysis evidenced that tissue damage was strongly related to the variable tissue thickness. These preliminary results seem to support the fact that endoscopic tunable laser ablation is feasible with a consistent damage/power correlation. Further tests are required to optimize the settings for applications on early GI tumors.

Comparative Effects of Non-Thermal Atmospheric Pressure Plasma on Migration and Invasion in Oral Squamous Cell Cancer, by Gas Type

PURPOSE

The fourth state of matter, plasma is known as an ionized gas with electrons, radicals and ions. The use of non-thermal plasma (NTP) in cancer research became possible because of the progresses in plasma medicine. Previous studies on the potential NTP-mediated cancer therapy have mainly concentrated on cancer cell apoptosis. In the present study, we compared the inhibitory effect of NTP on cell migration and invasion in the oral squamous cancer cell lines.

MATERIALS AND METHODS

We used oral squamous cancer cell lines (SCC1483, MSKQLL1) and different gases (N₂, He, and Ar). To investigate the mechanism of plasma treatment, using different gases (N₂, He, and Ar) which induces anti-migration and anti-invasion properties, we performed wound healing assay, invasion assay and gelatin zymography.

RESULTS

The results showed that NTP inhibits cancer cell migration and invasion of oral squamous cancer cell. In addition, focal adhesion kinase expression and matrix metalloproteinase-2/9 activity were also inhibited.

CONCLUSION

The suppression of cancer cell invasion by NTP varied depending on the type of gas. Comparison of the three gases revealed that N₂ NTP inhibited cell migration and invasion most potently via decreased expression of focal adhesion kinase and matrix metalloproteinase activity.

Efficacy of endoscopic mucosal resections for the management of small gastric adenomas with low-grade dysplasia

OBJECTIVE

Gastric adenoma with low-grade dysplasia (LGD) can progress to gastric cancer; however, the optimal therapeutic modality for LGD has not been established. The aim of this study was to assess the efficacy, safety of and local recurrence following endoscopic mucosal resection (EMR) for LGD. Specifically, we compared EMR with circumferential precutting (EMR-P) and EMR using a dual-channel endoscope (EMR-D) for the treatment of LGD ≤2 cm.

MATERIALS AND METHODS

A total of 158 lesions from 147 patients with LGD treated by EMR were retrospectively analyzed. The en bloc resection rate, complete resection rate, procedure time, complication rate and local recurrence rate were compared between EMR-P and EMR-D.

RESULTS

The en bloc resection and complete resection rates of EMR were 91.1% and 90.5%, respectively. The bleeding and perforation rates were 1.3% and 1.3%, respectively. The local recurrence rate following EMR was 2.2%. The en bloc resection and complete resection rates did not differ between EMR-P and EMR-D (88.2% vs. 92.5%, p = not significant (NS); and 90.2% vs. 90.7%, p = NS, respectively). The procedure time was significantly longer for EMR-P compared with EMR-D (16 (5-141) vs. 7 (2-48) min, p < 0.001), and the complication rate was significantly higher for EMR-P (7.8% vs. 0.0%, p = 0.010). Local recurrence was not found in EMR-P, whereas the recurrence rate was 3.2% in EMR-D.

CONCLUSION

EMR is an effective method for the treatment of LGD ≤2 cm. Compared with EMR-P, EMR-D appears to be the more effective, technically simple and safer method.

Effect of lipid peroxidation on membrane permeability of cancer and normal cells subjected to oxidative stress

We performed molecular dynamics simulations to investigate the effect of lipid peroxidation products on the structural and dynamic properties of the cell membrane. Our simulations predict that the lipid order in a phospholipid bilayer, as a model system for the cell membrane, decreases upon addition of lipid peroxidation products. Eventually, when all phospholipids are oxidized, pore formation can occur. This will allow reactive species, such as reactive oxygen and nitrogen species (RONS), to enter the cell and cause oxidative damage to intracellular macromolecules, such as DNA or proteins. On the other hand, upon increasing the cholesterol fraction of lipid bilayers, the cell membrane order increases, eventually reaching a certain threshold, from which cholesterol is able to protect the membrane against pore formation. This finding is crucial for cancer treatment by plasma technology, producing a large number of RONS, as well as for other cancer treatment methods that cause an increase in the concentration of extracellular RONS. Indeed, cancer cells contain less cholesterol than their healthy counterparts. Thus, they will be more vulnerable to the consequences of lipid peroxidation, eventually enabling the penetration of RONS into the interior of the cell, giving rise to oxidative stress, inducing pro-apoptotic factors. This provides, for the first time, molecular level insight why plasma can selectively treat cancer cells, while leaving their healthy counterparts undamaged, as is indeed experimentally demonstrated.

Clinical outcomes of argon plasma coagulation therapy for early gastric neoplasms

Background/Aims

Argon plasma coagulation (APC) has some merits in the treatment of gastric neoplasms including a shorter operative time and fewer complications compared with endoscopic mucosal resection or endoscopic submucosal dissection. However, there are few reports on the outcomes of gastric neoplasms treated using APC. The aim of this study was to evaluate APC in the treatment of early gastric neoplasms in terms of clinical efficacy, safety, and local recurrence.

Methods

We enrolled 28 patients who received APC therapy at the Kyungpook National University Hospital between May 2007 and April 2013. Clinical outcomes were analyzed.

Results

The median follow-up period was 24.8 months (range, 2 to 78). Among the 28 lesions treated using the APC procedure, tumor recurrence was encountered in seven lesions (25.0%). Recurrence was found in 50% (5/10) of single APC cases and 11% (2/18) of rescue APC cases. The mean time to recurrence was 16.1 months (range, 2 to 78). There were no serious APC-related complications such as perforation, bleeding, or infection.

Conclusions

APC therapy can be a useful treatment with a favorable safety profile for patients with early gastric neoplasms. However, further studies are necessary to determine the long-term prognosis of patients undergoing this treatment.

Acute gastric necrosis after routine oesophagogastroduodenoscopy with therapeutic argon plasma coagulation

A 56-year-old woman presented to the accident and emergency department with peritonitis 2 days after a routine oesophagogastroduodenoscopy. She was taken to theatre with the finding of gastric necrosis. Blood and peritoneal cultures grew group A haemolytic Streptococcus. Histology revealed normal vasculature, no volvulus but marked neutrophilia in the submucosa with an intact mucosa. The stomach was resected and the patient recovered in the intensive care unit but overwhelming acidosis progressed to multiorgan failure and treatment was eventually withdrawn. Acute phlegmonous gastritis has been well described in the literature but mainly before the advent of antibiotics. The most common organism is group A haemolytic Streptococcus (commonly found in throat infections) and predisposing factors include instrumentation. Should antibiotics be given at the start of an oesophagogastroduodenoscopy and should routine procedures be delayed if active upper respiratory tract infections are present?

Clinical outcomes of argon plasma coagulation for the treatment of gastric neoplasm

BACKGROUND

There are insufficient reports on the outcomes and local recurrence rates for gastric neoplasms treated using argon plasma coagulation (APC). The purpose of this study was to analyze the clinical outcomes in early gastric cancer or gastric adenoma patients following APC treatment.

METHODS

Seventy-one patients were enrolled and all underwent APC at the Asan Medical Center between July 2007 and August 2011. Clinical and oncological outcomes were analyzed.

RESULTS

The median follow-up period was 20 months (interquartile range 13-29 months). Among the 71 patients we evaluated, nonlifting after submucosal saline injection was found in 35 patients and 15 patients (21.2%) experienced local recurrence with a median period of 10 months (IQR 5-13 months). The rate of local recurrence was higher in the nonlifting group and the 40-W group than in the lifting group and the 60- or 80-W groups (31.4 vs. 11.1%, p = 0.045 and 31.7 vs. 6.7%, p = 0.017, respectively). Multivariate analysis showed that the power setting with the 40-W and nonlifting groups after submucosal injection was associated with local recurrence.

CONCLUSIONS

APC therapy after submucosal saline injection using high power (60 or 80 W) appears to be an effective alternative in the management of gastric neoplasm.

Argon plasma coagulation is safe and effective for treating smaller gastric lesions with low-grade dysplasia: a comparison with endoscopic submucosal dissection

BACKGROUND AND AIMS

The best therapeutic modality has not been established for gastric low-grade adenomas or dysplasia (LGD), which can progress to invasive carcinoma despite a low risk. This study aims to investigate the clinical efficacy, safety, and local recurrence after argon plasma coagulation (APC) treatment of gastric LGD compared with endoscopic submucosal dissection (ESD).

PATIENTS AND METHODS

A total of 320 patients with gastric LGD ≤ 2.0 cm treated with APC or ESD between 2004 and 2011 were retrospectively analyzed. We compared local recurrence rate, complication rate, procedure time, and admission to hospital between APC and ESD groups.

RESULTS

Of the 320 patients, 116 patients were treated with APC and 204 with ESD. During follow-up, local recurrence was more common in the APC group (3.8 %, 4/106) than the ESD group (0.5 %, 1/188; log-rank test P = 0.036). However, all patients with local recurrence (n = 5) were treated by additional APC, and followed up without further recurrences. ESD was complicated by two perforations (1.0 %, 2/204) compared with no perforations in the APC group (0 %, 0/116). Bleeding complications were not different between the APC (1.7 %, 2/116) and ESD (2.0 %, 4/204) groups. Procedure time was shorter in the APC (7.8 ± 5.1 min) than the ESD (53.1 ± 38.1 min) group (P < 0.001). The proportion of hospitalization was less in the APC group (31.0 %, 36/116) than the ESD group (100.0 %, 204/204) (P < 0.001).

CONCLUSIONS

APC can be a good treatment option for patients with LGD ≤ 2.0 cm.

Argon plasma coagulation for superficial esophageal squamous-cell carcinoma in high-risk patients

AIM: To evaluate the usefulness and safety of argon plasma coagulation (APC) for superficial esophageal squamous-cell carcinoma (SESC) in high-risk patients.

METHODS: We studied 17 patients (15 men and 2 women, 21 lesions) with SESC in whom endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and open surgery were contraindicated from March 1999 through February 2009. None of the patients could tolerate prolonged EMR/ESD or open surgery because of severe concomitant disease (e.g., liver cirrhosis, cerebral infarction, or ischemic heart disease) or scar formation after EMR/ESD and chemoradiotherapy. After conventional endoscopy, an iodine stain was sprayed on the esophageal mucosa to determine the lesion margins. The lesion was then ablated by APC. We retrospectively studied the treatment time, number of APC sessions per site, complications, presence or absence of recurrence, and time to recurrence.

RESULTS: The median duration of follow-up was 36 mo (range: 6-120 mo). All of the tumors were macroscopically classified as superficial and slightly depressed type (0-IIc). The preoperative depth of invasion was clinical T1a (mucosal cancer) for 19 lesions and clinical T1b (submucosal cancer) for 2. The median treatment time was 15 min (range: 10-36 min). The median number of treatment sessions per site was 2 (range: 1-4). The median hospital stay was 14 d (range: 5-68 d). Among the 17 patients (21 lesions), 2 (9.5%) had recurrence and underwent additional APC with no subsequent evidence of recurrence. There were no treatment-related complications, such as bleeding or perforation.

CONCLUSION: APC is considered to be safe and effective for the management of SESC that cannot be resected endoscopically because of underlying disease, as well as for the control of recurrence after EMR and local recurrence after chemoradiotherapy.

Endoscopic ablation therapy for gastrointestinal superficial neoplasia

AIM

  In Japan, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been widely accepted and standardized for the treatment of gastrointestinal superficial neoplasia.

METHODS

  In contrast, mucosal ablation techniques are more common in Western countries and a variety of endoscopic ablation modalities, including argon plasma coagulation (APC), photodynamic therapy (PDT) and lasers, are used.

RESULTS

  Recently developed modalities such as radiofrequency ablation (RFA) and cryotherapy are also available for the treatment of superficial lesions such as dysplasia of Barrett's esophagus.

CONCLUSION

  Although we should understand that the completeness of destruction of neoplastic tissue can only be judged at follow up, endoscopic ablation is a viable alternative to endoscopic resection for dysplasia and early-stage malignancies, especially for poor candidates of surgery or endoscopic resection.

Endoscopic submucosal dissection for gastric cancer

Endoscopic submucosal dissection (ESD) is a novel endoscopic treatment that enables a clinician to resect an early-stage gastric cancer in en bloc fashion. ESD is indicated for those cancers in which there is a high probability of en bloc resection and low probability of lymph node metastasis. The latter may be the limiting factor at institutions skilled at ESD. Several ESD techniques are available with similar outcomes. Thus, selection depends on operator preference and expertise. Gastrectomy with lymphadenectomy should be applied initially to those early gastric cancers with high probability of positive lymph nodes or as an additional treatment after ESD. Endoscopic mucosal resection (EMR) should be reserved for small, nonulcerated, intramucosal, differentiated cancers. Disadvantages of ESD in comparison with EMR are longer operation times and higher incidences of intraoperative bleeding and perforation, but the indication for ESD includes larger and ulcerative lesions not amenable to EMR.

Argon plasma coagulation treatment of hemorrhagic radiation proctopathy: the optimal settings for application and long-term outcome

BACKGROUND

No standard treatment exists for hemorrhagic radiation proctopathy (HRP). Recently it was reported that argon plasma coagulation (APC) is effective for HRP. However, previous studies documented complications such as ulcers, strictures, and perforations in as many as 20% of APC-treated patients.

OBJECTIVE

The aim of this study was to determine the optimal parameters for APC by using swine rectum and to assess the safety and effectiveness of APC in HRP patients.

DESIGN

Prospective case series.

SETTING

University teaching hospital.

PATIENTS

Sixty-five patients with HRP were prospectively enrolled between 2000 and 2010.

INTERVENTIONS

APC for HRP.

MAIN OUTCOME MEASUREMENTS

Optimal APC parameters, number of treatments, success rate, complications, clinical remissions.

RESULTS

APC in swine rectal wall ex vivo was optimal with a 40-W current, 1.2-L/min gas flow rate, and 2-second application, which was sufficient to treat the submucosal telangiectasia but did not adversely affect the muscle layer. Sixty-five patients (46 men, 19 women; median age 72 years) with HRP occurring at a mean of 20 months after radiotherapy were studied. Proctopathy was classified as grade A (mild) in 7 patients (10.8%), grade B (moderate) in 41 (63.1%), and grade C (severe) in 17 (26.2%). The treatment success rate was 98.5% after a median of 2 (range 1-5) APC sessions. The median clinical score for rectal bleeding was significantly decreased after APC (P < .0001), and the hemoglobin level was significantly increased (P < .0001). APC was well tolerated, and no significant side effects or complications occurred. During a mean follow-up of 34.6 months (range 3.6 -121.1 months), 4 patients (6.3%) had minor recurrent rectal bleeding and 60 (93.8%) remained in remission.

LIMITATIONS

Nonrandomized study.

CONCLUSIONS

HRP treatment with optimal APC settings yields a high success rate and long-lasting clinical remission with no significant complications.

Predictive factors for local recurrence after endoscopic resection for early gastric cancer: long-term clinical outcome in a single-center experience

BACKGROUND

Endoscopic resection is widely accepted as the primary treatment for early gastric cancer (EGC) without lymph node metastasis. A new and refined technique, endoscopic submucosal dissection (ESD), may prove to be more effective; however, incomplete resection and local recurrence present ongoing concerns. We sought to determine the clinicopathological features associated with local recurrence in patients with EGC following endoscopic resection.

METHODS

We enrolled in this study 239 EGC patients treated by endoscopic resection between January 2002 and January 2008.

RESULTS

Fifty EGC lesions were treated by conventional endoscopic mucosal resection (EMR group) and 189 EGC lesions were treated by ESD (ESD group). During the follow-up period (mean = 30.3 months), the rates for en bloc resection and complete resection (defined as en bloc resection with negative resection margin) were 64% (32/50) and 60% (30/50), respectively, in the EMR group, and 86.8% (164/189) and 79.9% (151/189), respectively, in the ESD group. We observed seven local recurrences in the ESD group, though only one with complete resection by ESD had a local recurrence. The EMR group showed a significantly higher recurrence rate than did the ESD group (18% vs. 3.7%, respectively, p < 0.001). Incomplete resection significantly increased local recurrence risk, and larger tumor size and use of EMR increased the risk for incomplete resection. Most lesions (3/4) treated with additional argon plasma coagulation for an initial recurrence had recurred again.

CONCLUSIONS

Despite the potential advantages in treating EGC with ESD, a risk for local recurrence remains. All patients treated with EMR, even with curative resection, and those with incomplete resection after ESD require conscientious surveillance for local recurrence. Furthermore, a large prospective study will be required to determine the best treatment modality for local recurrence.

Argon plasma coagulation with submucosal saline injection for gastric adenoma on outpatient basis

Gastric adenoma with low-grade dysplasia (LGD) is a less progressive disease than with high-grade dysplasia; nevertheless, a certain portion of lesions can progress. The purpose of this study was to evaluate the effectiveness of argon plasma coagulation (APC) with submucosa saline injections (APC-SSI) for gastric adenoma with LGD on an outpatient department (OPD) basis. We included 57 patients with 64 lesions of gastric adenoma with LGD. Endoscopic type was flat elevated in 58 lesions and central depressed in 6 lesions. Normal saline was injected into the submucosa under the lesion before APC. APC was performed to the lesion and its surrounding mucosa. After treatment, patients underwent regular endoscopy follow-ups. One case each of pneumoperitoneum and Mallory-Weiss tearing occurred and could be managed with conservative care. One case of overt bleeding occurred after 2 weeks and was treated with APC. After 19.5 months of follow-up, four residual adenomas (6.3%) were found and treated with additional APC-SSI. Fourteen metachronous lesions were noted in eight patients (14.0%). Twelve lesions were adenoma with LGD and two lesions were intramucosal adenocarcinoma. APC-SSI is an effective and safe treatment modality for gastric adenoma with LGD on an OPD basis and it is recommended for patients with risk factors of endoscopic mucosal resection (EMR). After treatment of gastric adenoma, meticulous follow-up endoscopy is recommended for detection of metachronous lesions.

Treatment of gastrointestinal diseases with second-generation argon plasma coagulation: an analysis of 260 cases

AIM: To investigate the safety and efficacy of the second-generation argon plasma coagulation (VIO APC) for gastrointestinal diseases.

METHODS: During 2007-09-14/2008-10-22, 260 patients were treated using VIO APC in a total of 289 sessions. For various indications, the new VIO APC device was used. Safety and efficacy of VIO APC were recorded after each individual treatment session.

RESULTS: The mean number of treatment sessions required using VIO APC in various indications was 1.11 ± 0.31. In the palliative treatment of gastric adenocarcinoma, it was 2.50; in endoscopic hemostasis, it was 1.23; in the treatment of colorectal polypi, it was 1.15, in the treatment of upper gastrointestinal polypi, it was 1.03, in the management of self-expand stent overgrowth or tumor stenosis, it was 1.17; in the ablation of Barrett's esophagus, it was 1.13; in the ablation of gastric dysplasia, gastritis verrucosa, gastric xanthelasma and gastric or duodenal liparomphalus, only 1 session was needed. Minor complications (pain, dysphagia/odynophagia, asymptomatic gas accumulation in the intestinal wall) were observed in 10.1%-20% sessions, but no major complications (hemorrhage, perforation, stenosis) were observed.

CONCLUSION: VIO APC is effective and safe for various gastrointestinal conditions. It can be widely applied to daily endoscopic treatment.

Mucosal injury caused by argon plasma coagulation in rabbits

AIM: To investigate mucosal injury induced by argon plasma coagulation (APC) in rabbits.

METHODS: The mucosal injury of large intestine of rabbits was induced by APC with argon gas flow 2.0, 2.5, 3.0 and 4.0 L/min in two pulsed modes. Thickness of mucosa was measured by endoscopic ultra sound (EUS). Qualitative histologic analysis of each site of APC application was performed by light microscopy.

RESULTS: EUS showed high echo in mucosa while low echo in submucosa and muscularis propria. Depth of injury was significantly correlated with argon gas flow (P = 0.006), power setting (P = 0.023) and duration of pulse (P = 0.030).

CONCLUSION: APC is a safe method in treatment of colon disease. The lower argon gas flow and short durations have the lowest risk of deep tissue injury.

Submucosal Injection of Normal Saline can Prevent Unexpected Deep Thermal Injury of Argon Plasma Coagulation in the in vivo Porcine Stomach

BACKGROUND/AIMS

There have been several reports of thermal injury induced by argon plasma coagulation (APC) in animal models, but no follow-up studies have revealed the actual thermal injury.

METHODS

APC was performed on the stomachs of two living minipigs with and without prior submucosal injection of normal saline. The power and argon gas flow were set to 60 watts and 2 L/min, respectively, and pulse durations of 5, 10, and 20 seconds were used. One of the minipigs was killed immediately thereafter and the other was killed 1 week later.

RESULTS

The minipig killed immediately showed only subtle differences between noninjected and injected injuries under all the conditions, and the usefulness of prior submucosal injection was not obvious. However, the minipig killed 1 week later had a deep ulcer extending to the deeper muscle layer at the noninjected site where APC had been applied for 20 seconds, whereas tissue injury of the injected site was limited to the submucosal layer.

CONCLUSIONS

Unexpected tissue damage can occur even using a short-duration APC. Prior submucosal injection for APC might be a safer alternative technique, especially in a thinner and narrower gut wall.

Successful use of endoscopic argon plasma coagulation for patients with early gastric cancer and diabetes mellitus

We report on two patients with gastric tumors (early cancer and adema) and diabetes mellitus who were treated with argon plasma coagulation (APC) therapy. Case 1. A 78-year-old woman visited the Nippon Medical School Musashi Kosugi Hospital because of epigastric pain. An early gastric cancer (IIc) in the anterior wall of the gastric antrum was diagnosed on the basis of the results of a gastric endoscopy examination. The patient had had diabetes mellitus for 18 years and had injected insulin (NovoRapid 30 Mix, 72 units/day) by herself everyday for 10 years. Case 2. A 61-year-old man was referred to our hospital because of a gastric tumor. A gastric adenoma in the anterior of the gastric antrum was diagnosed on the basis of the results of a gastric endoscopy examination. The patient had had diabetes mellitus for 12 years and had been taking oral medication for 2 years. Endoscopic APC was performed in both patients to remove the gastric tumors. These patients have been well for 28 months and 30 months, respectively, after undergoing APC treatment. APC therapy appears to be a safe and useful treatment for patients with diabetes and gastric mucosal lesions.

Prospective evaluation of a new high-power argon plasma coagulation system (hp-APC) in therapeutic gastrointestinal endoscopy

OBJECTIVE

The aim of this study was to prospectively evaluate a new high-power argon plasma coagulation system (hp-APC) in therapeutic gastrointestinal (GI) endoscopy.

MATERIAL AND METHODS

From February to June 2005, 216 patients (167 M (77.3%), mean age 66 years) underwent treatment with hp-APC in a total of 275 sessions. Main indications were additive ablation therapy in Barrett's esophagus, palliative treatment of esophageal cancer, gastric polyps/carcinomas, angiodysplasias, Zenker's diverticula, and duodenal adenomas. The new hp-APC device (VIO 300 D with APC 2) was used (15-120 W) in upper GI endoscopy, push-enteroscopy, and double-balloon enteroscopy.

RESULTS

The mean number of treatment sessions required was 1.7 (1-5). For palliative tumor ablation in the esophagus, the number of sessions was 2.3 (1-5). Minor complications (pain, dysphagia, neuromuscular irritation, asymptomatic gas accumulation in the intestinal wall) were observed in 29/216 patients (13.4%). Major complications (perforation, stenosis occurred) in 2 patients (0.9%).

CONCLUSIONS

Hp-APC appears to be safe and effective in the treatment of various GI condition using different types of endoscopes including double-balloon enteroscopy. Because of the low number of treatment sessions required, hp-APC could be used as an alternative to Nd:YAG laser treatment in tumor debulking.

Submucosal injection of normal saline may prevent tissue damage from argon plasma coagulation: an experimental study using resected porcine esophagus, stomach, and colon

Argon plasma coagulation (APC) is considered to be a safe thermocoagulation technique, but some reports show perforation and deformity during and after APC. In this study, we investigated the usefulness of prior submucosal injection for APC. APC over the mucosa was performed on fresh resected porcine esophagus, stomach, and colon with prior submucosal injection of normal saline (injection group) and without it (control group). The depth of tissue damage increased linearly with pulse duration up to the shallower submucosal layer in both groups. After that, tissue damage in the injection group remained confined to the shallower submucosal layer under any condition, whereas that in the control group continued to extend. The tissue damages of the injection groups were significantly (P<0.05) shallower than those of the control groups that reached the deeper submucosal layer in all the organs. Submucosal injection of normal saline before the application of APC may limit tissue damage and prevent perforation and deformity.

New generation argon plasma coagulation in flexible endoscopy: ex vivo study and clinical experience

BACKGROUND AND AIM

A new argon plasma coagulation (APC) system was developed to improve the conduction characteristics of existing systems and to achieve a true non-contact procedure. We evaluated the new system in an ex vivo experiment and in two different clinical cases.

METHODS

Swine gastric walls were cauterized at various current settings and time intervals. The diameter and penetration depth of the cauterized areas were measured. We also describe the use of this method to treat patients with gastric hemorrhagic hereditary telangiectasias and a mucosal gastric cancer.

RESULTS

The ex vivo study revealed an improved maintenance of current conduction and greater control of the extent and penetration depth of the cauterization effects on tissue using the new APC system. In the clinical cases, hemorrhagic telangiectasias and an early stage gastric cancer were treated successfully without relapse using the new system.

CONCLUSIONS

Improved current conduction and controllability of cauterization corresponding to emission time were demonstrated for the new APC. The new system allows expeditious superficial cauterization of a wide area without any contact with tissue. The therapeutic effect appeared favorable compared with previous APC devices for gastrointestinal applications.

Argon plasma coagulation for early gastric cancer: technique and outcome

BACKGROUND

Argon plasma coagulation (APC) is a noncontact technique for tissue coagulation. APC has been used to treat early gastric cancer in patients who cannot undergo EMR or open surgery, but a standard procedure for APC is lacking.

OBJECTIVE

Our objectives were to assess the clinical usefulness of APC in patients with early gastric cancer.

DESIGN

This was a small, retrospective pilot study.

SETTING

All patients were treated at the Department of Gastroenterology, Kitasato University East Hospital, Sagamihara, Japan.

METHODS

We studied 40 patients with early gastric cancer in whom both EMR and open surgery were contraindicated. The macroscopic tumor type was superficial elevated in 11 patients, superficial depressed in 27, and superficial elevated plus superficial depressed in two. The histologic classification was intestinal type in 37 patients and diffuse type in 3.

INTERVENTION

From January 1998 through March 1999, all patients received one session of APC. From April 1999 through August 2001, all patients received two sessions of APC. From September 2001 through March 2002, an additional session of APC was given only to patients who had large protruding lesions, depressed lesions 2 cm or greater in diameter, or submucosal invasion.

MAIN OUTCOME MEASUREMENTS

The main outcome measurements were residual tumor or recurrence of early gastric cancer.

RESULTS

Intestinal-type intramucosal carcinoma disappeared after one or two sessions of APC. Submucosal and diffuse-type tumors had a high risk of residual tumor cells because of inadequate treatment after one session of APC. However, such lesions were locally controlled by follow-up APC.

LIMITATIONS

This was a small, retrospective pilot study. Confirmation of long-term outcome is required.

CONCLUSIONS

Small early gastric carcinomas can be successfully treated by a single session of APC. Larger protruding-type lesions and submucosal tumors are likely to require two sessions of APC.

Endoscopic therapy of early gastric cancer

Endoscopic therapy of early gastric cancer is applicable for differentiated-type mucosal carcinomas that have an extremely low potency of lymph-node metastasis. Among various kinds of endoscopic therapy, endoscopic mucosal resection is the most recommended procedure, because pathological evaluation of affected tissues is available using this method. Recently, endoscopic submucosal dissection, a novel method of endoscopic mucosal resection, has gained interest as a more reliable therapeutic procedure. In the present chapter several issues will be presented on endoscopic therapy for early gastric cancer, including endoscopic diagnosis of early gastric cancer, currently accepted indications of endoscopic therapy, and the possibility of extending the indication and techniques used for mucosal resection.

Interventional endoscopy

PURPOSE OF REVIEW

This review provides an updated summary of gastric interventional endoscopy. Relevant original articles and topic reviews are highlighted in the areas of infection control, light sedation, hemostasis, endoscopic mucosal resection, and endoscopic placement of enteric devices.

RECENT FINDINGS

Several key findings are worth noting: the increased use of propofol by nonanesthesiologists for deep sedation with minimal adverse side effects, the adaptation of tissue adhesive agents for the treatment of bleeding gastric varices, the successful treatment of early gastric cancer by endoscopic mucosal resection, and the development of direct percutaneous endoscopic jejunostomy tubes for patients at high risk of aspiration.

SUMMARY

These recent developments in the field of interventional endoscopy have already made a great impact on clinical care. More advanced procedures can be performed safely while the patient is under deep sedation. Yet, these developments have not slowed down the need for improvement in interventional endoscopy. Researchers continue to look for smaller instruments, better optics, and more advanced accessories. This constant state of flux marks the field of interventional endoscopy and ensures its progress.