Shin-ei Kudo

Peroral endoscopic myotomy (POEM) for esophageal achalasia.

BACKGROUND Peroral endoscopic myotomy (POEM) was developed by our group to provide a less invasive permanent treatment for esophageal achalasia. PATIENTS AND METHODS POEM was performed in 17 consecutive patients with achalasia (10 men, 7 women; mean age 41.4 years). A long submucosal tunnel was created (mean length 12.4 cm), followed by endoscopic myotomy of circular muscle bundles of a mean total length of 8.1 cm (6.1 cm in distal esophagus and 2.0 cm in cardia). Smooth passage of an endoscope through the gastroesophageal junction was confirmed at the end of the procedure. RESULTS In all cases POEM significantly reduced the dysphagia symptom score (from mean 10 to 1.3; P = 0.0003) and the resting lower esophageal sphincter (LES) pressure (from mean 52.4 mmHg to 19.9 mmHg; P = 0.0001). No serious complications related to POEM were encountered. During follow-up (mean 5 months), additional treatment or medication was necessary in only one patient (case 17) who developed reflux esophagitis (Los Angeles classification B); this was well controlled with regular intake of protein pump inhibitors (PPIs). CONCLUSIONS The short-term outcome of POEM for achalasia was excellent; further studies on long-term efficacy and on comparison of POEM with other interventional therapies are awaited.

Diagnosis of colorectal tumorous lesions by magnifying endoscopy.

BACKGROUND The magnifying colonoscope allows 100-fold magnified viewing of the colonic surface. METHODS We examined 2050 colorectal tumorous lesions by magnifying endoscopy, stereomicroscopy, and histopathology and classified these lesions according to pit pattern. Based on stereomicroscopy, lesions with a type 1 or 2 pit pattern were nontumors, whereas lesions with types 3s, 3L, 4, and/or 5 pit patterns were neoplastic tumors. RESULTS The pit patterns observed by magnifying endoscopy were fundamentally similar to those demonstrated in stereomicroscopic images. When the diagnosis by magnifying endoscopy was compared with the stereomicroscopic diagnosis, there was agreement in 1130 of 1387 lesions (81.5%). True neoplasms could be differentiated from non-neoplastic lesions. Of lesions with a type 5 pit pattern with a bounded surface, 11 of 22 (50%) were found to be invasive cancers with involvement of the submucosal layer. If this pit pattern is found to involve a relatively broad area of the mucosal surface, extensive malignant invasion (sm-massive) should be strongly suspected. CONCLUSIONS The magnifying colonoscope provides an accurate instantaneous assessment of the histology of colorectal tumorous lesions. This may help in decision making during colonoscopy.

Narrow-band imaging system with magnifying endoscopy for superficial esophageal lesions

BACKGROUND By assessing the intrapapillary capillary loop in esophageal mucosa, magnifying endoscopy can play an important role in the evaluation of superficial esophageal lesions. A newly developed narrow-band imaging system was applied to magnifying endoscopy in a clinical setting; the benefit of the narrow-band imaging system was evaluated. METHODS Forty-one patients (37 men, 4 women; mean age 63.5 [7.3] years) were enrolled between March 2002 and January 2003 in the study. Endoscopy was performed with a magnifying endoscope, a standard video-endoscopic system, and a narrow-band imaging system. The assessment consisted of 3 phases: a numerical analysis of the red, green, blue color value of endoscopic images, creation of model images, and assessment on the actual images. In the numerical analysis, the red, green, blue color value for intrapapillary capillary loop and background mucosa were obtained, and the ratio and contrast value were calculated. RESULTS In the numerical analysis, both the ratio and the contrast value between the intrapapillary capillary loop and background mucosa were statistically different. Based on an evaluation of created model images, almost all assessors found the narrow-band imaging system to be superior. In the assessment of actual images, the narrow-band imaging system improved overall accuracy for depth of invasion, especially for inexperienced endoscopists. CONCLUSIONS The narrow-band imaging system improved the accuracy of magnifying endoscopy for assessment of esophageal lesion.

Colonoscopic Diagnosis and Management of Nonpolypoid Early Colorectal Cancer

Nonpolypoid colorectal neoplasms are grossly classified into three groups: slightly elevated (small flat adenomas), laterally spreading, and depressed. Flat adenomas are not invasive until they are rather large, whereas depressed lesions can invade the submucosa even when they are extremely small. Nonpolypoid lesions are difficult to detect and are often overlooked. Keys to detect them are their slight color change, interruption of the capillary network pattern, slight deformation of the colonic wall, spontaneously bleeding spots, shape change of the lesion with insufflation and deflation of air, and interruption of the innominate grooves. Spraying of indigo carmine dye helps to clarify the lesions. A pit pattern analysis with a zoom colonoscope is useful for the diagnosis and staging of early colorectal cancer. Small flat adenomas are thought to be precursors of protruded polyps and lateral spreading tumors, whereas depressed lesions are thought to grow endophytically and become advanced cancers. Small depressed lesions are treated with an endoscopic mucosal resection (EMR) technique; but when they massively invade the submucosa, surgical resection is indicated. Laterally spreading tumors are not as invasive despite their large size and therefore are good indications for the EMR or piecemeal EMR method. Small flat adenomas need not be treated urgently, as almost none is invasive. Accurate diagnosis with dye-spraying and zoom colonoscopy is vital for deciding the treatment strategy.

Endoscopic diagnosis and treatment of early colorectal cancer.

Abstract. Colorectal adenomas and early cancers are grossly classified into three groups: protruded, flush or slightly elevated (so-called flat adenomas), and depressed. Protruded lesions and flat adenomas are not invasive until they are rather large, whereas depressed lesions can invade the submucosa even when very small. It is not difficult to detect protruded and flat adenomas, but depressed carcinomas are often overlooked. Keys to the detection of depressed carcinomas are a slight color change, bleeding spots, interruptions of the capillary network pattern, slight deformation of the colonic wall, shape change of the lesion with insufflation and deflation of air, and interruption of the innominate grooves by the lesion. Spraying of indigo carmine dye helps to clarify the lesions. Pit pattern analysis with magnifying colonoscopy is useful for diagnosis of early colorectal cancer. Pit pattern analysis and histologic examination suggest that depressed carcinomas probably have arisen de novo, without going through an adenomatous step. Some adenomas appear at first to have a depression, but such cancer-mimicking adenomas with pseudodepression must be distinguished from depressed carcinomas because they are quite different in nature. Protruded and flat adenomas can usually be removed with polypectomy or hot biopsy techniques. Depressed carcinomas are treated with an endoscopic mucosal resection (EMR) technique; but when they massively invade the submucosa, surgical resection is indicated. Some neoplastic lesions, which we call laterally spreading tumors, extensively and circumferentially spread along the colonic wall, although they are short in height. They tend to have a rather benign nature despite their large size; therefore EMR or a piecemeal EMR method is indicated.

Per-Oral Endoscopic Myotomy: A Series of 500 Patients.

BACKGROUND After the first case of per-oral endoscopic myotomy (POEM) at our institution in 2008, the procedure was quickly accepted as an alternative to surgical myotomy and is now established as an excellent treatment option for achalasia. This study aimed to examine the safety and outcomes of POEM at our institution. STUDY DESIGN Per-oral endoscopic myotomy was performed on 500 consecutive achalasia patients at our institution between September 2008 and November 2013. A review of prospectively collected data was conducted, including procedure time, myotomy location and length, adverse events, and patient data with short- (2 months) and long-term (1 and 3 years) follow-up. RESULTS Per-oral endoscopic myotomy was successfully completed in all patients, with adverse events observed in 3.2%. Two months post-POEM, significant reductions in symptom scores (Eckardt score 6.0 ± 3.0 vs 1.0 ± 2.0, p < 0.0001) and lower esophageal sphincter (LES) pressures (25.4 ± 17.1 vs 13.4 ± 5.9 mmHg, p < 0.0001) were achieved, and this persisted at 3 years post-POEM. Gastroesophageal reflux was seen in 16.8% of patients at 2 months and 21.3% at 3-year follow-up. CONCLUSIONS Per-oral endoscopic myotomy was successfully completed in all cases, even when extended indications (extremes of age, previous interventions, or sigmoid esophagus) were used. Adverse events were rare (3.2%), and there were no mortalities. Significant improvements in Eckardt scores and LES pressures were seen at 2 months, 1 year, and 3 years post-POEM. Based on our large series, POEM is a safe and effective treatment for achalasia; there are relatively few contraindications, and the procedure may be used as either first- or second-line therapy.

Submucosal endoscopic tumor resection for subepithelial tumors in the esophagus and cardia

BACKGROUND AND STUDY AIMS Resection of submucosal tumors by means of endoscopy has been reported using a variety of techniques, but cannot be performed safely in tumors originating from the muscularis propria. Using the submucosal tunnel created by the technique of peroral endoscopic myotomy (POEM), we report the first series describing the new technique of submucosal endoscopic tumor resection (SET) for tumors of the esophagus and cardia. PATIENTS AND METHODS SET was attempted in nine consecutive patients with tumors (size >2cm) of either the esophagus or cardia with clinical indications for lesion removal. Following creation of a submucosal tunnel from 5 cm above the tumor, as described previously, the tumor was dissected from the overlying mucosa/submucosa and then carefully removed from the muscular layer using triangle-tip and insulated-tip knives. Following specimen retrieval through the tunnel, the orifice was closed by clips. RESULTS Of the nine patients, two had tumors that were too large (60 mm and 75 mm, respectively) to allow safe removal due to loss of endoscopic overview. All remaining tumors (maximal tumor extension 12-30 mm) could be resected safely using this method. No complications occurred and follow-up was unremarkable. On histology, all tumors were resected completely (one gastrointestinal stromal tumor, five leiomyomas). The technique had to be modified in one patient with an aberrant pancreas. CONCLUSIONS SET is a promising new technique for selected submucosal tumors in the esophagus and cardia up to a size of 4 cm and should be studied further.

Peroral Endoscopic Myotomy for Esophageal Achalasia: Technique, Indication, and Outcomes

Peroral endoscopic myotomy (POEM) has been developed as an incisionless, minimally invasive endoscopic treatment intending a permanent cure for esophageal achalasia. The concept of endoscopic myotomy was first reported about 3 decades ago, but the direct incision method through the mucosal layer was not considered to be a safe and reliable approach. A novel method of endoscopic myotomy was developed and established by the authors. In this article, the current techniques, applications, and clinical results of POEM are described.

Diagnosis of colorectal lesions with the magnifying narrow-band imaging system

BACKGROUND Narrow-band imaging (NBI) emphasizes the surface microvasculature of the GI tract and may help in detecting small neoplasms. OBJECTIVE The aim of this study was to clarify the value of the NBI system in tissue characterization and differential diagnosis. DESIGN A prospective study. SETTING Digestive Disease Center of Showa University Northern Yokohama Hospital. PATIENTS The subjects were 495 patients who, from January 2006 to June 2007, underwent a complete colonoscopic examination. A total of 617 lesions were evaluated in the 495 patients (33 hyperplastic polyps, 532 adenomas, 52 submucosally invasive [T1] cancers). RESULTS Most hyperplastic polyps showed a faint pattern. The vascular patterns of adenomas were mainly the network pattern or the dense pattern. The major vascular patterns of cancers were the irregular pattern and the sparse pattern. The irregular pattern was characteristic for protruded or flat-elevated cancers, whereas the sparse pattern was unique for depressed cancers. When we assumed that the faint pattern was diagnostic for hyperplastic polyps, we could differentiate between neoplastic and non-neoplastic lesions with a sensitivity of 90.9% and a specificity of 97.1%. Likewise, irregular and sparse patterns were assumed to be indices of massively invasive submucosal cancer, the sensitivity was 100%, the specificity was 95.8%, and the accuracy rate was 96.1%. LIMITATIONS This study was performed at a single center. CONCLUSIONS The NBI system was valuable for distinguishing between neoplastic and non-neoplastic lesions, as well as between cancers and adenomas. Vascular pattern analysis can also be a promising tool for determining treatment selection, either endoscopy or surgery.

Endoscopic mucosal resection of the colon: the Japanese technique.

Early colorectal neoplasms, especially flat-type and depressed-type lesions, should be treated with an EMR technique. In general because depressed-type lesions, in contrast to flat-type or protruded-type lesions, tend to invade the submucosa rapidly, they ought to be treated by EMR at an early stage. Histopathologically in the case of lesions that only minimally invade the submucosa without vessel invasion (sm1a and sm1b without vessel invasion), a treatment can be completed with EMR. Massive submucosal invasive cancers ought to be resected by surgical treatment because of the risk of recurrence or metastasis. In addition, pit pattern diagnosis with magnifying colonoscopy is useful to determine a therapeutic method for colonic neoplasms. Lesions with the type VN pit pattern represent malignancy and usually invade the submucosa massively, so it is better to treat them surgically from the outset. Endoscopic mucosal resection should be conducted under fully controlled endoscopy to prevent complications. EMR is a superior therapeutic method and will be performed frequently in the future. It is necessary for colonoscopists to determine a suitable therapy for each colorectal neoplastic lesion. They also need to master the EMR technique in the correct manner.