ENDOSCOPIC RESECTION FOR EARLY GASTRIC CANCER AND FUTURE EXPECTATIONS

CHARACTERIZATION OF THE MUCIN PHENOTYPE CAN PREDICT GASTRIC CANCER RECURRENCE AFTER ENDOSCOPIC MUCOSAL RESECTION

BACKGROUND

Endoscopic mucosal resection is still considered an accepted treatment for early gastric cancer for selected cases. Histopathologic criteria for curative endoscopic resection are intramucosal well-differentiated adenocarcinoma, lateral and deep margins free of tumor, no histological ulceration, and no venous or lymphatic embolism. A 5% local recurrence rate has been described even when all the above-mentioned criteria are met. On the other hand, antigen expression by tumoral cells has been related to the biological behavior of several tumors.

OBJECTIVE

To evaluate whether early gastric cancer mucin immunoexpression, p53 and Ki-67, can predict recurrence after endoscopic mucosal resection, even when standard histopathologic criteria for curative measures have been attempted.

METHODS

Twenty-two patients with early gastric cancer were considered to have been completely resected by endoscopic mucosal resection. Local recurrence occurred in 5/22 (22.7%). Immunohistochemical study was possible in 18 (81.8%) resected specimens. Patients were divided in two groups: those with and those without local recurrence. They were compared across demographic, endoscopic, histologic data, and immunohistochemical factors for MUC2, MUC5a, CD10, p53, and Ki-67.

RESULTS

Mucin immunoexpression allowed a reclassification of gastric adenocarcinoma in intestinal (10), gastric (2), mixed (4), and null phenotypes (2). Mixed phenotype (positive for both MUC2 and MUC5a) was found in 80% of cases in the local recurrence group, while the intestinal type (positive MUC2 and negative MUC5a) was found in 76.9% of cases without local recurrence (P=0.004). Other observed features did not correlate with neoplastic recurrence.

CONCLUSION

The mixed phenotype of early gastric adenocarcinoma is associated with a higher probability of local recurrence after endoscopic mucosal resection.

Endoscopic Resection Compared with Gastrectomy to Treat Early Gastric Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Endoscopic resection and gastrectomy are treatment modalities for early gastric cancer, but their relative benefits and risks are unclear. We conducted a systematic review and meta-analysis to compare endoscopic resection and gastrectomy for treating early gastric cancer.

METHODS

We searched PubMed, Embase, and the Cochrane Library until April 2015 for studies comparing endoscopic resection with gastrectomy for treatment of early gastric cancer. Outcome measures were five-year overall survival (OS), length of hospital stay and postoperative morbidity. We calculated pooled hazard ratio (HR), weighted mean difference (WMD) and odds ratio (OR) using random effects models.

RESULTS

Six studies comprising 1,466 patients (618 endoscopic resection and 848 gastrectomy) met inclusion criteria. Five-year OS was similar between endoscopic resection and gastrectomy (HR, 1.06; 95% CI: 0.61 to 1.83). Endoscopic resection was associated with shorter hospital stays (WMD, -6.94; 95% CI: -7.59 to -6.29) and reduced overall postoperative morbidity (OR, 0.36; 95% CI: 0.17 to 0.74).

CONCLUSIONS

While five-year OS is similar between endoscopic resection and gastrectomy, endoscopic resection offers a shorter hospital stay and fewer complications than gastrectomy for treating early gastric cancer. Endoscopic resection is a reasonable treatment for early gastric cancer with a negligible risk of lymph node metastasis.

Risk factors for bleeding evaluated using the Forrest classification in Japanese patients after endoscopic submucosal dissection for early gastric neoplasm

BACKGROUND/AIMS

Bleeding remains a serious complication after endoscopic submucosal dissection (ESD). Second-look endoscopy for hemostasis helps prevent post-ESD bleeding. We investigated the relationships between patient characteristics, tumor characteristics, and the Forrest classification for exposed vessels on artificial ulcers after ESD and evaluated whether hemostasis during second-look endoscopy was useful for preventing post-ESD bleeding.

PATIENTS AND METHODS

We analyzed 250 patients (265 lesions) who underwent ESD for gastric neoplasms. Vessels classified by Forrest classifications during scheduled second-look endoscopy were analyzed for associations with patient characteristics, tumor characteristics, and recurrent bleeding.

RESULTS

Two of 250 patients (0.8%) underwent emergency hemostatic endoscopy before scheduled second-look endoscopy. The remaining 248 patients (99.2%) underwent scheduled second-look endoscopy on the day after ESD. Patients with Forrest classification Ia, Ib, or IIa vessels had a significantly higher risk for recurrent bleeding after scheduled second-look endoscopy compared with patients with IIb or III vessels according to univariate analysis (P<0.05) and multivariate logistic regression analysis (odds ratio: 3.45; 95% confidence interval: 1.04-11.41; P=0.042). Univariate analysis indicated that hemodialysis correlated significantly with the presence of Ia, Ib, or IIa vessels compared with that of IIb or III vessels found during second-look endoscopy (P<0.05). Multivariate analysis indicated a significant relationship between hemodialysis and recurrent bleeding after second-look endoscopy (odds ratio: 10.05; 95% confidence interval: 1.97-51.26; P=0.006).

CONCLUSION

Hemodialysis is a risk factor for post-ESD bleeding. Proper classification of exposed vessels within post-ESD ulcers according to the Forrest classification using second-look endoscopy might help predict or prevent recurrent bleeding.

The incidence of "silent" free air and aspiration pneumonia detected by CT after gastric endoscopic submucosal dissection

BACKGROUND

Although endoscopic submucosal dissection (ESD) is feasible as a treatment for early gastric cancer, it requires great skill to perform and may place patients at increased risk of a number of complications, including perforation and aspiration pneumonia.

OBJECTIVE

To investigate the incidence of "silent" free air without endoscopic perforation and aspiration pneumonia detected by CT after ESD and risk factors for the development of these 2 conditions.

DESIGN

Prospective cohort study.

SETTING

Single academic center.

PATIENTS

This study involved 87 patients with a total of 91 malignancies.

INTERVENTION

All patients underwent chest and abdominal CT and blood biochemistry analysis before and 1 day after ESD.

MAIN OUTCOME MEASUREMENTS

The incidence of silent free air and aspiration pneumonia after ESD and the related risk factors.

RESULTS

Silent free air was identified in 37.3% of patients without perforation. Tumor location (the upper portion of the stomach), the presence of a damaged muscular layer during ESD, and procedure time, but not specimen size, were significantly associated with silent free air (P = .006, P = .04, P = .02, and P = .53, respectively). According to the receiver-operating characteristic analysis, the resulting cutoff value of the procedure time for silent free air was 105 minutes (67.7% sensitivity, 65.4% specificity). Only procedure time (≥ 105 minutes) was an independent predictor of silent free air development (odds ratio 3.23; 95% confidence interval, 1.21-8.64; P = .02). On the other hand, aspiration pneumonia was seen in 6.6% of patients. Silent free air and aspiration pneumonia did not affect hospitalization.

LIMITATIONS

Single center and small number of patients.

CONCLUSIONS

Silent free air is frequently observed after ESD, and longer procedure time (≥ 105 minutes) was an independent risk factor for silent free air. However, silent free air and aspiration pneumonia detected by CT are not associated with clinically significant complications.

Endoscopic submucosal dissection of early gastric neoplasia with a water jet-assisted knife: a Western, single-center experience

BACKGROUND

Endoscopic submucosal dissection (ESD) of early gastric neoplasia has not yet been established in Western countries because of a lack of data and the difficult, time-consuming, and hazardous nature of the method. Some of the technical limitations may be overcome by use of a water jet-assisted knife, which allows a combination of a high-pressure water jet and electrosurgical interventions.

OBJECTIVE

To evaluate the efficacy and safety of water jet-assisted ESD (WESD) with a water jet-assisted knife in selected patients with early gastric neoplasia.

DESIGN

Single-center, prospective study.

PATIENTS

This study involved 29 consecutive patients (13 female; median age 61 years; age range 35-93 years) with early gastric neoplasia that met the expanded criteria of the Japanese Gastric Cancer Association. Histology of biopsies had shown gastric adenocarcinoma in 21 cases, adenoma in 8 case, and suspicion of a GI stromal tumor in 1 case. The median maximal diameter of the lesions was 20 mm (range 10-40 mm).

INTERVENTION

All procedures were done with patients under sedation with propofol. The water jet-assisted knife was used for setting coagulation markers around the neoplastic lesions, then for circumferential incision and dissection in combination with repeated submucosal injection of saline solution with a water jet system. Bleeding was treated with diathermia by use of the water jet-assisted knife or hemostatic forceps in case of failure or larger vessels. Clips were used for closure of perforations.

MAIN OUTCOME MEASUREMENTS

Complete resection of neoplasia, procedure time, complication and recurrence rates.

RESULTS

According to endoscopic criteria, complete resection of the targeted area could be achieved in all cases, with an en bloc resection rate of 90%. The median procedure duration was 74 minutes (range 15-402 minutes). Exchange of the device was needed in only 10 cases because of severe bleeding from larger vessels, which could be managed by use of hemostatic forceps. The 30-day morbidity rate was 4 of 30 (13.8%) because of postprocedure pain in 3 cases and delayed bleeding in 1 case. A 93-year-old patient died the night after WESD without evidence of a procedure-related complication. Histology of the resected specimens showed adenocarcinoma in 20 cases, adenoma in 7, no neoplasia in 2, and a plasmacytoma in 1. Complete resection (R0) was histologically confirmed in 18 of 28 patients (64.3%) with resected neoplastic specimens. A horizontal or vertical neoplasia-free margin could not be confirmed in 9 cases and 1 case, respectively. Complete local remission of neoplasia was achieved in 25 of 28 patients (89.3%) who were followed over a median period of 22 months (range 6-44 months). In 1 patient, a metachronous gastric adenocarcinoma was identified 54 weeks after initial WESD.

LIMITATIONS

Noncontrolled study with a limited number of patients.

CONCLUSION

The use of a water jet-assisted knife simplifies ESD because exchange of devices is rarely needed. WESD promises to be effective and safe. The study demonstrates that the high rates of en bloc resection of early gastric neoplasia reported in Asia can be reproduced in Western referral centers. However, histology may not always confirm complete resection of horizontal tumor margins. In spite of the unfavorable histology results, the high rate of complete local remission of neoplasia promises that surgical treatment of early gastric neoplasia can be avoided in the majority of cases.

Indication, strategy and outcomes of endoscopic submucosal dissection for colorectal neoplasm

Although endoscopic submucosal dissection (ESD) for colorectal neoplasm is a promising endoscopic therapy with a high rate of successful en bloc resection, ESD for colorectal neoplasm is not a health-care service provided by Japanese public heath insurance, yet. Now, ESD for colorectal neoplasm has been approved as an 'advanced medical treatment' system, which is a partial-care service provided by Japanese public health insurance with individual payment of medical expenses, and the indication for ESD for colorectal neoplasm has been under debate. In our hospital, a total of 348 colorectal neoplasms underwent ESD using the FlexKnife and the FlushKnife, and 317 lesions (91%) were resected en bloc. Perforation occurred in eight cases (2%) and they were not critical and did not require emergent surgery. Delayed bleeding occurred in 16 cases (4%) and they were able to be controlled without transfusion and were not critical. The major impact of the advanced medical treatment system on clinical practice in our hospital was the increased incidence of adenocarcinoma and increased tumor size in the lesions that underwent ESD. It is thought that the application of the advanced medical treatment system resulted in careful selection of lesions for ESD while maintaining the principle of en bloc resection. We expect that a new, revised indication that covers recurrent carcinoma after endoscopic therapy will be indicated when ESD for colorectal neoplasm becomes a health-care service provided by Japanese public health insurance.

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.

Self-limiting risk of metachronous gastric cancers after endoscopic resection

BACKGROUND

Since endoscopic resection (ER) has been established as a treatment for early gastric cancer, metachronous multiple cancers have become a problem. It is unclear whether the risk of metachronous cancer is self-limiting or permanent. The aim of this study was to evaluate the incidence of multiple cancers after ER during a long-term follow-up study.

PATIENTS AND METHODS

A total of 234 patients who received initial ER for early gastric cancers were evaluated retrospectively. ER included endoscopic mucosal resection and endoscopic submucosal dissection. Patients were followed up with endoscopy for 3.0-19.6 years (median, 5.0 years), including 40 patients surveyed for more than 10 years. Accessory cancers detected after ER, but which could be retrospectively viewed in pre-ER pictures, were evaluated in the metachronous group.

RESULTS

Thirty patients (12.8%) developed 36 metachronous multiple cancers. The median interval between the discovery of metachronous cancer and the initial ER was 3.2 years; the longest interval was 9.7 years. Eight (22.2%) of the 36 metachronous cancers could be detected retrospectively in the picture record from pre-ER. The Kaplan-Meier curve of cumulative incidence of metachronous cancers stopped increasing after 10 years of follow up.

CONCLUSIONS

Although the residual gastric mucosa after ER is thought to be a high-risk environment, the high risk may only be the result of occult synchronous cancers. It is probable that the high risk of metachronous cancers is not continuous after 10 years.

Endoscopic submucosal dissection with sheath-assisted counter traction for early gastric cancers

AIM

Endoscopic submucosal dissection (ESD) is associated with frequent complications, such as bleeding and perforation. The procedure is technically difficult, requires considerable skill and is longer than conventional endoscopic mucosal resection (EMR). Thus, non-invasive tools and methods are needed to facilitate direct visualization of the submucosal layer during ESD.

METHODS

An insulation-tipped (IT) knife was inserted into one channel, and a conventional injection sheath was inserted to the other channel of a double-channel fiberscope. The submucosal layer was lifted via a circumferential incision using the conventional injection sheath for visualizing cutting lines, and the submucosal layer under the lesion was directly dissected from the underlying muscularis propria.

RESULTS

Sheath-assisted traction resulted in successful ESD with en bloc resection in all 25 patients. Hemostasis and manipulation of blood vessels were uncomplicated and dissection was completed safely, without either bleeding or perforation. The movement of the sheath was not suppressed while lifting the submucosal layer and the IT knife could be moved freely, which allowed submucosal dissection independently of the sheath movement.

CONCLUSION

Sheath-assisted traction ESD, using simple materials and methods, has several advantages over other standard traction methods. Our procedure is straightforward, safe, non-invasive, cost-effective and uses readily available instruments to enhance visualization of cutting lines.

Randomized controlled study of EMR versus endoscopic submucosal dissection with a water-jet hybrid-knife of esophageal lesions in a porcine model

BACKGROUND

Endoscopic submucosal dissection (ESD) seems to be more effective than EMR for curative resection of GI mucosal neoplasia. However, ESD is technically difficult, hazardous, and time consuming. New technologies may overcome these drawbacks.

OBJECTIVE

Our purpose was to compare a new simplified ESD technique with conventional EMR.

DESIGN

Prospective, randomized, and controlled trial in anesthetized pigs.

METHODS

A total of 25 esophageal areas with a diameter of 20 mm were marked with coagulation points in 6 pigs under general anesthesia. These lesions were then randomized to either EMR by use of the cap technique or ESD. Submucosal injection of saline solution was used for both methods. ESD was performed with a hybrid-knife (ESDH), which allows cutting and coagulation as well as a needleless, tissue-selective hydrodissection through an axial water-jet channel with a preselected pressure by using a high-pressure water-jet system (ErbeJet 2). Intraoperative bleedings were treated with hemostatic forceps.

MAIN OUTCOME MEASUREMENTS

A comparison of the rates of complete resection of the lesions, the number and the size of resected specimens, the complication rate, and the procedural duration.

RESULTS

Thirteen lesions were randomized to EMR and 12 to ESDH. ESDH achieved complete resection significantly more frequently than EMR (10/12 vs 6/13; P = .05). All ESDH resections were performed as a single piece, whereas a mean (SD) of 2.5 +/- 0.9 resections were needed for EMR (P < .05). The mean (SD) areas of the specimen were 3.63 +/- 1.20 cm(2) in the ESDH group and 1.83 +/- 0.78 cm(2) in the EMR group (P < .0001). ESDH was performed with a larger amount of fluid for injection and hydrodissection compared with EMR (78.1 +/- 32.8 mL vs 20.9 +/- 7.6 mL; P < .001). The procedural duration was longer for ESDH than for EMR (28.2 +/- 11.9 minutes vs 12.2 +/- 4.9 minutes; P < .001). ESDH and EMR caused bleedings in 6 of 12 and 5 of 13 of the cases (P = .09), respectively. Hemostasis could be achieved in all cases. There was no perforation in either group.

LIMITATIONS

Resection of artificial non-neoplastic lesions, small numbers, an animal trial.

CONCLUSIONS

ESDH achieves complete resection of esophageal lesions significantly more frequently with a fewer number of specimens than EMR. ESDH is more time consuming, but the procedural duration seems to be shorter than conventional ESD because there is no need for exchange of devices for injection and cutting. The easy use of water-jet-assisted repeated injections of fluids may explain why ESDH was as safe as EMRC.

Increased risk of lymph node metastasis in mucosal gastric cancer with extra indication for endoscopic mucosal resection

BACKGROUND

Selected cases of clinical mucosal gastric cancer can be treated endoscopically. But mucosal gastric cancer, which has a higher incidence of lymph node metastasis, should be treated by gastrectomy with lymph node dissection. Laparoscopy-assisted gastrectomy is usually indicated for the surgical treatment of mucosal gastric cancer.

STUDY DESIGN

From April 2005 to December 2007, 148 consecutive patients with clinical mucosal gastric cancer who underwent laparoscopy-assisted gastrectomy were investigated to clarify the clinicopathologic findings in this patient group.

RESULTS

Of the patients who underwent gastrectomy, 93 (63%) had tumors>20 mm in diameter and 92 (62%) had undifferentiated cancer. The frequency of lymph node metastasis was 8% (12 patients). One patient had second-compartment lymph node metastasis (station 8a). In patients with lymph node metastasis, 11 (92%) had an ulcer scar and 11 (92%) had undifferentiated tumors. None of the patients met the criteria for extended endoscopic submucosal dissection.

CONCLUSIONS

The incidence of lymph node metastasis in patients with mucosal gastric cancer in whom gastrectomy is indicated is higher than reported previously. More careful consideration is needed for the possibility of lymph node metastasis in this era of endoscopic submucosal dissection.

A new technique for gastric endoscopic submucosal dissection: peroral traction-assisted endoscopic submucosal dissection

BACKGROUND

Compared with conventional EMR, endoscopic submucosal dissection (ESD) has a higher en bloc resection rate and complete resection rate, regardless of tumor size, in treating gastric neoplasms. However, ESD leads to more complications, such as bleeding or perforation, and, in particular, needs more procedure time than a conventional EMR.

OBJECTIVE

To report a new technique for ESD, peroral traction-assisted ESD with suture material, to perform easier and more rapid procedures in treating gastric neoplasms and to report the technique's early results.

DESIGN

A case series.

SETTING

A tertiary medical center.

PATIENTS AND METHODS

A total of 15 patients with gastric adenomas or early gastric cancers larger than 10 mm in diameter were consecutively enrolled. After marking around the periphery of the lesion, submucosal injection, followed by circumferential mucosal incision with a Flex-knife and an insulation-tipped knife, was conducted. After that, one hemostatic clip, tied by using a white silk suture, was applied at a site of the lesion suitable for oral traction. During submucosal dissection, the applied suture material was pulled to the oral side. Additional tractions were applied as needed.

MAIN OUTCOME MEASUREMENTS

En bloc resection rate, procedure time, complications.

RESULTS

All lesions were resected en bloc with free lateral and vertical margins by using this technique. The mean longest lesion size and specimen size were 18.1 mm (range 11-28 mm) and 43.7 mm in diameter (range 25-64 mm), respectively. The mean procedure time was 49.6 minutes (range 28-90 minutes). There was no significant bleeding that required blood transfusion or perforation related to the procedures.

LIMITATIONS

Single endoscopist, small patient number.

CONCLUSION

Peroral traction-assisted ESD with suture material is useful in treating gastric neoplasms located in various regions of the stomach. It may make ESD procedures easier, faster, and safer under better direct vision of the submucosal layer.

Prognostic significance of intestinal claudins in high-risk synchronous and metachronous multiple gastric epithelial neoplasias after initial endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is useful in en bloc curative resection and enables patients with early gastric carcinoma (GC) to have a better quality of life. But metachronous recurrence of GC at other sites in the stomach has become a major issue after initial ESD. The purpose of the present paper was to examine gastric (claudin-18) and intestinal claudin (claudin-3 and claudin-4) expression in early GC on immunohistochemistry to clarify the association with clinicopathology, mucin phenotypes, microsatellite instability (MSI) status and the incidence of synchronous and metachronous gastric epithelial neoplasias after initial ESD. According to intestinal claudin expression, a total of 73 early GC were divided into two groups: intestinal claudin-positive (I-CLDN(+)) phenotype (n = 52; 71%); and intestinal claudin-negative (I-CLDN(-)) phenotype (n = 21; 29%). Although no significant association was found with clinicopathology and the MSI status, the I-CLDN(+) early GC correlated with the mucin phenotypes and had a significantly higher incidence of synchronous and metachronous multiple GC and gastric adenomas (P = 0.049). These results indicate that early GC demonstrating I-CLDN(+) phenotype have a high risk of synchronous and metachronous secondary gastric epithelial neoplasias.

Endoscopic submucosal dissection used for treating early neoplasia of the foregut using a combination of knives

BACKGROUND

Endoscopic submucosal dissection (ESD) has emerged as a novel technique for achieving en bloc resection for early esophageal or gastric carcinoma limited to the mucosa. The authors report their experience with a combination of various devices to treat early neoplasia of the foregut using the ESD technique.

METHODS

In this prospective case series, ESD was performed for early esophageal or gastric carcinoma limited to the mucosa. These lesions were staged by endoscopic ultrasonography before resection. Magnifying endoscopy and chromoendoscopy were used to locate the tumor and define the margin. The resection was accomplished with submucosal dissection using the insulated tip knife, the hook knife, and the triangular tip knife. The resected specimen was examined systematically for the lateral and deep margins.

RESULTS

From January 2004 to March 2006, ESD was performed to manage 30 cases of early gastric or esophageal carcinoma. For 29 of these patients, R0 resection was successfully achieved. The mean operating time was 84.6 min. One patient experienced reactionary hemorrhage 12 h after resection, which was controlled endoscopically. There was no perforation. Most of the circumferential mucosal incisions were performed using the insulated tip knife (76.6%), whereas submucosal dissection was accomplished with a combination of various knives. One of the specimens showed involvement of the lateral margin, whereas another patient had two areas of new early gastric cancer 6 months after the initial procedure. These patients received salvage laparoscopically assisted gastrectomy.

CONCLUSIONS

Endoscopic submucosal dissection to manage early neoplasia of the foregut can be achieved safely and effectively with a combination of knives.

Reliability of endoscopic esophageal mucosectomy using TxHood, a multipurpose treatment hood

Endoscopic mucosectomy, comprising both endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), is a minimally invasive treatment for patients with early esophageal carcinoma. The use of ESD is appropriate for mucosal lesions of any size. However, ESD techniques are relatively difficult and can lead to serious complications such as perforation and massive bleeding, which have been reported more frequently after ESD than after EMR. This study describes a novel technique for ESD using a newly designed multipurpose treatment hood (TxHood) as well as basic experiments to ensure its safety. The TxHood includes various therapeutic tools such as an electric needleknife, a snare wire, and an injection needle, and the lines can be selected freely before insertion of an enodoscope covered by a TxHood. The main techniques for ESD are endoscopic submucosal saline injections on demand through a working channel of the endoscope or TxHood and a cut or swing cut with a needleknife attached to the TxHood. Moreover, the target area can be grasped with a grasping forceps through a working channel of the endoscope to obtain effective countertraction. In these experiments, an electric needleknife set parallel to the shaft of the endoscope offered safety and ease of handling for the dissecting procedures. Altogether, 16 resections of mucosa with an average size of 3.5 x 2.5 cm (range, 2 x 2 to 7 x 4 cm) were performed. The average time required for each targeted endoscopic resection area was about 15 min. No perforations or instances of uncontrollable bleeding occurred. In conclusion, this basic study demonstrates that the new ESD technique with the TxHood provides a useful treatment for early esophageal carcinoma and may be applicable for all mucosal or submucosal tumors in the gastrointestinal tract.

Assessment of microsatellite instability status for the prediction of metachronous recurrence after initial endoscopic submucosal dissection for early gastric cancer

The technique of endoscopic submucosal dissection (ESD) has been developed for en bloc resection of early gastric cancer (EGC); however, little is known about the risk of metachronous cancer in the remnant stomach after initial ESD. In this study, we investigated the correlation between microsatellite instability (MSI) status and the incidence of metachronous recurrence of gastric cancer. According to the genetic/molecular background determined with MSI status and expression levels of hMLH1 and p53 tumour suppressor, 110 EGCs removed with ESD were subclassified into three groups: the mutator/MSI-type (8%), suppressor/p53-type (45%) and unclassified type (47%). Interestingly, patients with the mutator/MSI-type tumour had a high incidence (67%) of metachronous recurrence of gastric cancer within a 3-year observation after initial ESD, which was significantly higher than those with the suppressor/p53-type and unclassified type tumours (P<0.01). Although we investigated mucin phenotypes, there was no correlation between mucin phenotype and the recurrence of EGC. These findings suggest that subclassification of molecular pathological pathways in EGCs is required for the assessment of patients with a high risk of recurrent gastric cancer. The information delivered from our investigation is expected to be of value for decisions about therapy and surveillance after ESD.