Search

Endoscopic self-expandable metal stent (SEMS) placement has emerged as an effective palliative treatment for inoperable malignant gastric outlet obstruction (GOO). In spite of successful stent placement, some patients complain of ongoing dysphagia and vomiting. Most reported data on SEMS to date are about technical success of different types of stents and low complication rates. The aim of this study was to evaluate the associated factors of clinical failure after endoscopic SEMS placement for inoperable malignant GOO.A total 122 patients who underwent successful endoscopic SEMS placement for malignant GOO in an academic referral center were included in the analyses. We retrospectively evaluated variables associated with clinical outcomes after successful SEMS placement.The clinical success rate was 81.1%. The common causes of GOO were pancreatic (39%) and gastric cancers (32%). The mean length of the stents (± standard deviation) was 10.06 ± 2.42 cm. Multivariate analysis revealed that gallbladder cancer (p = 0.016, OR 6.486, 95% CI, 1.509-59.655), poor performance status (ECOG ≥ 3) (p = 0.001, OR 10.200, 95% CI, 2.435-42.721), the presence of carcinomatosis peritonei (p0.001, OR 35.714, 95% CI, 5.556-250.000) and the failure of endoscope passage (p = 0.039, OR 6.945, 95% CI, 1.101-43.818).Our results suggest that gallbladder cancer, poor performance status (ECOG ≥ 3) and the presence of carcinomatosis peritonei related with clinical failure of palliative SEMS placement.

To evaluate the safety and effectiveness of fixation of the fully covered self-expandable metal stent (SEMS) placement using a silk thread for complete closure of an anastomotic leak. An anastomotic leak is a life-threatening complication after gastrectomy. Although the traditional treatment of choice was surgical re-intervention, an endoscopic SEMS can be used alternatively. During the study period, we retrospectively reviewed consecutive patients who received a modified covered SEMS capable of being fixed using a silk thread (Shim technique) due to an anastomotic leak after gastrectomy to prevent stent migration. Demographic data, stent placement and removal, clinical success, time to resolution, and complications were evaluated. A total of 7 patients underwent fully covered SEMS with a silk thread placement for an anastomotic leak after gastrectomy to treat gastric cancer. The patients’ mean age was 71.3 ± 8.0 years. Man sex was predominant (85.7%). All patients’ American Society of Anesthesiologists (ASA) scores were between I and III. Total gastrectomy was performed in 5 patients (71.4%) and proximal gastrectomy was performed in 2 patients (28.6%). The time between gastrectomy and stent insertion was 22.3 ± 11.1 days. The size of the leaks was 27.1 ± 11.1 mm. Technical success and complete leak closure were achieved in all patients. Stent migration was absent. All stents were removed between 4 and 6 weeks. Delayed esophageal stricture was found in 1 patient (14.2) and successfully resolved after endoscopic balloon dilation. For an anastomotic leak after gastrectomy, fully covered SEMS placement with a silk thread is an effective and safe treatment option without stent migration. The stent extraction time between 4 and 6 weeks was optimal without severe complications.

Endoscopic forceps biopsy is insufficient for a definitive diagnosis of dysplastic lesions. It is difficult to decide clinical management of gastric indefinite neoplasia diagnosed by endoscopic forceps biopsy when early gastric cancer (EGC) is macroscopically suspected. The aim of this study was to discuss the final results of gastric indefinite neoplasia and associated clinical factors predictive of early gastric cancer. The medical records of 119 patients who were diagnosed with gastric indefinite neoplasia by index forceps biopsy were retrospectively reviewed. The initial endoscopic findings were analyzed, and predictive factors of EGC were evaluated. The final pathologic diagnoses of 119 patients included early gastric cancer (n = 26, 21.8 %), adenoma (n = 6, 5.0 %) and non-neoplasm (n = 87, 73.1 %). Univariate analysis showed that lesion size greater than 10 mm, surface nodularity and surface redness were associated risk factors. In the multivariate analysis, lesions diameter (p = 0.021, OR 11.401, 95 % CI 1.432–90.759) and surface redness (p = 0.014, OR 3.777, 95 % CI 1.306–10.923) were significant risk factors. Patients with gastric indefinite neoplasia with larger size (≥10 mm) and surface redness might need further diagnostic investigation rather than simple follow-up endoscopy.

Delayed gastric emptying (DGE) is one of the most troublesome complications after subtotal gastrectomy for gastric cancer. We evaluated operative and perioperative variables to assess for independent risk factors of DGE caused by anastomosis edema.The study retrospectively reviewed clinical data of 382 consecutive patients who underwent subtotal gastrectomy for gastric cancer between 2009 and 2011 at a single institution.Delayed gastric emptying had occurred in twelve patients (3.1%). Univariate analysis revealed high body mass index (25kg/m2), open gastrectomy, and Billroth II or Roux-en Y reconstructions to be significant factors for delayed gastric emptying. Multivariate analysis identified high body mass index and open gastrectomy as predictors of delayed gastric emptying.To avoid delayed gastric emptying, surgeons should take care in creating the gastrointestinal anastomosis, particularly in patients with high BMI or in cases of open gastrectomy.

Gastric cancer stem cells (GCSCs) have been successfully isolated from patients. However, the molecular mechanisms underlying the self-renewal of GCSCs and their relationship with the microenvironment are poorly characterized. GCSCs and cancer-associated fibroblasts (CAFs) were cultured directly from gastric cancer patients. The self-renewal of GCSCs was assayed by sphere formation assay and in vivo tumorigenicity. Expression of neuregulin1 (NRG1) was examined by immunohistochemistry, real-time PCR and western blotting. CAFs increased the self-renewal of GCSCs by secreting NRG1. NRG1 activated NF-κB signaling and this activation regulated GCSC self-renewal. Moreover, NF-κB-active GCSCs were tumorigenic, however NF-κB-inactive GCSCs were not. The overexpression of NRG1 in stromal cells and cancer cells was observed in the tumor tissues of gastric cancer patients and was associated with clinical stage lymph node metastasis and survival in gastric cancer patients. In addition, we also found that NRG1 can regulate the proliferation and invasion of gastric cancer cells. These results indicate that NRG1, which can be secreted by CAFs or cancer cells, promotes progression of gastric cancer by regulating the self-renewal of GCSCs and its overexpression is associated with a prognosis of gastric cancer.

Pure squamous cell carcinoma (SCC) of the stomach is rare and resembles SCC arising elsewhere in the body. The pathogenesis of SCC remains unclear and controversial. At present

Purpose: A duodenal stump fistula is one of the most severe complications after gastrectomy for gastric cancer. We aimed to analyze the risk factors for this problem, and to identify the methods used for its prevention and management. Methods: We retrospectively reviewed the clinical data of 716 consecutive patients who underwent curative gastrectomy with a duodenal stump for gastric cancer between 2008 and 2013. Results: A duodenal stump fistula occurred in 16 patients (2.2%) and there were 2 deaths in this group. Univariate analysis revealed age >60 years (odds ratio [OR], 3.09; 95% confidence interval [CI], 0.99–9.66), multiple comorbidities (OR, 4.23; 95% CI, 1.50–11.92), clinical T stage (OR, 2.91; 95% CI, 1.045-8.10), and gastric outlet obstruction (OR, 8.64; 95% CI, 2.61–28.61) to be significant factors for developing a duodenal stump fistula. Multivariate analysis identified multiple comorbidities (OR, 3.92; 95% CI, 1.30–11.80) and gastric outlet obstruction (OR, 5.62; 95% CI, 1.45–21.71) as predictors of this complication. Conclusion: Multiple comorbidities and gastric outlet obstruction were the main risk factors for a duodenal stump fistula. Therefore, preventive methods and aggressive management should be applied for patients at high risk.

Cancer stem cells have been hypothesized to drive the growth and metastasis of tumors. Because they need to be targeted for cancer treatment, they have been isolated from many solid cancers. However, cancer stem cells from primary human gastric cancer tissues have not been isolated as yet. For the isolation, we used two cell surface markers: the epithelial cell adhesion molecule (EpCAM) and CD44. When analyzed by flow cytometry, the EpCAM(+)/CD44(+) population accounts for 4.5% of tumor cells. EpCAM(+)/CD44(+) gastric cancer cells formed tumors in immunocompromised mice; however, EpCAM(-)/CD44(-), EpCAM(+)/CD44(-) and EpCAM(-)/CD44(+) cells failed to do so. Xenografts of EpCAM(+)/CD44(+) gastric cancer cells maintained a differentiated phenotype and reproduced the morphological and phenotypical heterogeneity of the original gastric tumor tissues. The tumorigenic subpopulation was serially passaged for several generations without significant phenotypic alterations. Moreover, EpCAM(+)/CD44(+), but not EpCAM(-)/CD44(-), EpCAM(+)/CD44(-) or EpCAM(-)/CD44(+) cells grew exponentially in vitro as cancer spheres in serum-free medium, maintaining the tumorigenicity. Interestingly, a single cancer stem cell generated a cancer sphere that contained various differentiated cells, supporting multi-potency and self-renewal of a cancer stem cell. EpCAM(+)/CD44(+) cells had greater resistance to anti-cancer drugs than other subpopulation cells. The above in vivo and in vitro results suggest that cancer stem cells, which are enriched in the EpCAM(+)/CD44(+) subpopulation of gastric cancer cells, provide an ideal model system for cancer stem cell research.

This paper proposes a compensation algorithm of analog rotor position errors due to nonideal sinusoidal encoder signals. The position sensors such as resolvers or incremental encoders are being replaced by sinusoidal encoders that offer much higher resolution. However, the periodic position errors are generated by the gain and offset errors between sine and cosine signals. In this paper, the effects of the gain and offset errors are analyzed by using dq-axis component. The analog position errors can be easily corrected by integral operation of the d-axis component. Therefore, the proposed algorithm does not need additional hardware and much computation time. The validity of the proposed algorithm is verified through experimental results.

To retrospectively measure the diagnostic performance of prospective computed tomographic (CT) results obtained by using 16- or 64-detector row scanners in the detection of peritoneal metastases (PMs) in patients with advanced gastric cancer.The institutional review board approved this retrospective study and waived the need to obtain patient consent. In 498 patients with gastric cancer (stageor= T2) who were undergoing surgery, the presence of PM was prospectively rated as grade 0 (absent), grade 1 (equivocal), or grade 2 (present) on CT scans (0.67 or 2 mm thick) that were interpreted by interactively adjusting the viewing thickness and viewing plane. The CT readings were retrospectively compared with surgical and pathologic findings. In patients in whom the presence of PM was rated as grade 1 or less, factors predictive of PM were identified by testing variables, including patient and tumor characteristics, with univariate tests and multivariate logistic regression analysis.Fifty-three patients (10.6%) had confirmed PM. When only grade 2 was considered to indicate a positive CT reading, sensitivity and specificity were 28.3% (15 of 53) and 98.9% (440 of 445), respectively. With the threshold of grade 1 or greater indicating a positive reading, sensitivity and specificity were 50.9% (27 of 53) and 96.2% (428 of 445), respectively. In the patients with grades of 1 or less, the significant factors predictive of PM were greater tumor size and T stage.The sensitivity of PM detection is limited, even with modern CT techniques. In patients whose CT results are not definitely positive for PM, staging laparoscopy is still recommended if the aforementioned two predictive factors (greater tumor size and T stage) are suspected.

Background Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are widely performed. Indications for these procedures have been extended in Korea and Japan. The aim was to evaluate whether these extended indications are safe. Methods All patients who had surgery for early gastric cancer at Seoul National University Bundang Hospital between May 2003 and December 2007 were identified from a prospective database. Lymph node status was examined in patients who met extended indications for EMR and had undergone surgical resection. Results Of patients with mucosal cancers, 129 met extended indications for EMR or ESD and three (2·3 per cent) had lymph node metastasis. Of the 52 submucosal cancers meeting extended indications for EMR or ESD, two (4 per cent) had lymph node metastasis. Differentiated mucosal cancers without ulcer formation did not have lymph node metastasis, irrespective of size. Conclusion Extending the indications for EMR and ESD according to the Japanese Gastric Cancer Association guidelines carries an increased risk of lymph node metastasis. For cancers meeting these criteria, treatment by gastric resection with lymph node dissection should still be considered. A well differentiated mucosal cancer of any size without ulceration may be considered as an extended indication for EMR or ESD.

Objective To analyze 3-year actual disease-free survival after laparoscopy-assisted gastrectomy for gastric cancer on the assumption that 3-year disease-free survival may represent 5-year overall survival. Design Retrospective analysis. Setting Department of surgery of a university hospital. Patients A total of 197 patients who underwent laparoscopy-assisted gastrectomy for gastric cancer from May 1998 to September 2007 and who were followed up for more than 3 years. Main Outcome Measures Feasibility and long-term survival rate with survival analysis by the Kaplan-Meier method. Results Subtotal and total gastrectomies were performed in 178 and 19 patients, respectively. The scope of the lymph node dissections were D1 + β (n = 152) and D2 (n = 45). There were 153, 28, 8, 6, 1, and 1 patients in stages Ia, Ib, II, IIIa, IIIb, and IV, respectively. The median follow-up was 45 months (range, 1-113 months), and there were 7 recurrences. Multivariate analysis of disease-specific survival showed that depth of invasion and lymph node metastasis influenced the prognosis independently. The actual 3-year disease-free survival rate for all patients was 96.9%. The 173 patients with early gastric cancer and 24 with advanced gastric cancer showed 98.8% and 79.1% actual 3-year disease-free survival rates, respectively. Conclusions Laparoscopy-assisted gastrectomy is acceptable oncologically in early gastric cancer if 3-year disease-free survival represents 5-year overall survival. Laparoscopy-assisted gastrectomy may also play an important role in the treatment of advanced gastric cancer.

The purpose of this study is to introduce the technical details of double stapling Roux-en-Y (R-Y) reconstruction and evaluate its short-term results.Twenty-three patients who underwent a laparoscopy assisted distal gastrectomy with R-Y reconstruction between May 2007 and December 2008 were enrolled in this study. This investigation analyzed the clinicopathological data, the surgical data, and the postoperative outcome.There were 14 males and 9 females, and the mean age was 60.1 years (range, 51-66 years). The mean number of the retrieved lymph nodes was 37.3 (range, 17-67), and stage IA in 22 patients and stage IB in 1 patient. The total operation time was 198.3 min (range, 165-210 min), the intracorporeal operation time was 118.0 min (range, 95-130 min), and the extracorporeal operation time was 80.2 min (range, 70-90 min). The mean length of the incision was 3.5 cm (range, 3.2-3.8 cm). There was no leakage, stricture, or Roux stasis syndrome, and 3 cases (13%) of remnant gastritis occurred postoperatively.Double stapling R-Y anastomosis can be performed easily, quickly, and safely, and it is particularly useful in a laparoscopy-assisted distal gastrectomy. This method is advantageous in terms of the operation time and the cost effectiveness.

We evaluated the feasibility of laparoscopy-assisted gastrectomy in elderly patients with gastric cancer.We performed a retrospective analysis of 632 patients who underwent laparoscopy-assisted gastrectomy from May 2003 to December 2007 at Seoul National University Bundang Hospital. Postoperative complication rates were compared between patients older and younger than 70 years of age.Of the 632 patients, 515 (81.5%) were younger than 70 years and 117 (18.5%) were aged 70 years or older. Significant differences in the prevalence of cardiovascular disease and hypertension were observed in patients older than 70 years (p0.05). Although the overall complication rates of the patients younger and older than 70 years were 12.6% and 17.9%, respectively, there was no statistically significant difference between groups (p=0.12). Multiple logistic regression analysis revealed that comorbidities with hypertension or with liver cirrhosis were the only variables that correlated independently with postoperative complications.Complications after laparoscopy-assisted gastrectomy for patients older than 70 years of age with gastric cancer were similar to those of younger patients. But a careful approach is required when patients older than 70 years of age have hypertension or liver cirrhosis.

Laparoscopic partial gastric resection is widely accepted as a treatment for gastric submucosal tumors (SMTs). However, SMTs of either end of the stomach are generally managed by subtotal gastrectomies or total gastrectomies. This study was conducted to evaluate surgical techniques for management of SMTs located at the ends of the stomach.Among 63 patients who were diagnosed and underwent laparoscopic surgery for gastric SMTs at Seoul National University Bundang Hospital from May 2003 to May 2007, 11 SMTs located at the ends of the stomach were identified. The clinicopathologic results of these 11 SMTs were analyzed.Laparoscopic partial wedge resections or tumor excisions were successfully performed on all patients except for those who had prepyloric tumors. Six men and five women had SMTs at the ends of the stomach. The patients ranged in age from 21-63 years (mean 43.4 +/- 13.5 years). Of six esophagogastric junctional tumors that showed low, homogeneous contrast enhancement on computed tomography (CT) scans, five were treated by laparoscopic transgastric enucleation and one by tumor-everting resection. One esophagogastric junctional tumor that leaned toward the fundus and showed a 6-cm-diameter endophytic mass with heterogeneous enhancement on CT scan was resected by laparoscopic wedge resection. The mean operation time was 100 min (range 60-210 min). Three laparoscopy-assisted distal gastrectomies and one laparoscopic wedge resection were performed on SMTs located near the prepyloric antrum. There were no intra- or postoperative complications. Duration of postoperative hospital stay ranged from 4-7 days.Laparoscopic local resection is an effective treatment for SMTs located at the esophagogastric junction and can be used instead of a total or proximal gastrectomy. However, gastrectomies should be considered for SMTs located near the pylorus because of the small volume of the lower third of the stomach.

Purpose: Laparoscopic gastric wedge resection is a standard treatment for removing gastric submucosal tumors (SMTs). So far, however, there have been few reports of single-incision laparoscopic intragastric wedge resection. Our aim was to describe this procedure and our experience with it. Methods: From January 2010 to December 2013, a total of 21 consecutive patients with gastric SMTs underwent singleincision intragastric resection at our institution. Their clinicopathologic data were analyzed retrospectively. Results: The patients consisted of nine men and 12 women with a mean age of 51.9 ± 12.9 years (22?69 years). Their mean body mass index was 22.6 ± 2.0 kg/m2. Mean tumor size was 2.4 ± 0.7 cm, with the following anatomic distribution: esophagogastric junction in three patients, fundus in twelve, upper body in three, and lower body in two. Mean operating time was 68.6 ± 12.0 minutes. There were no conversions to open surgery and no major intraoperative complications. Time to resumption of water intake was 1.4 ± 0.5 days. Mean hospital stay was 4.9 ± 1.7 days. There were no recurrences or deaths during the mean 19-month follow-up. Conclusion: Single-incision intragastric wedge resection is a feasible and safe procedure. It is especially efficient for treating small endophytic gastric SMTs located on the upper and mid portion of the stomach.

A method to generate an isolated single-cycle attosecond pulse from the interaction of a high-power femtosecond laser pulse with a nano-tube array is demonstrated using a two-dimensional relativistic particle-in-cell simulation. The radiation mechanism is relativistic nonlinear Thomson scattering from the electrons in a target material. Coherent radiation is emitted in the direction of specular reflection for the incident laser pulse while the electrons make a bunch size smaller than a wavelength of the laser pulse. Maintaining the coherence of the radiation from the electrons is essential to get an intense attosecond duration, which is achieved by using a nano-tube array target and a sharply increasing laser pulse. Optimal conditions for attosecond pulse generation are investigated by parameter scanning over plasma density, target thickness and laser pulse duration.

Background: Lamina-associated polypeptides 2 (LAP2) is a nuclear protein that connects the nuclear lamina with chromatin. Although its critical roles in genetic disorders and hematopoietic malignancies have been described, its expression and roles in digestive tract cancers have been poorly characterized. Methods: To examine the expression of LAP2 in patient tissues, we performed immunohistochemistry and real-time PCR. To examine motility of cancer cells, we employed Boyden chamber, wound healing and Matrigel invasion assays. To reveal its roles in metastasis in vivo, we used a liver metastasis xenograft model. To investigate the underlying mechanism, a cDNA microarray was conducted. Results: Immunohistochemistry in patient tissues showed widespread expression of LAP2 in diverse digestive tract cancers including stomach, pancreas, liver, and bile duct cancers. Real-time PCR confirmed that LAP2 beta is over-expressed in gastric cancer tissues. Knockdown of LAP2 beta did not affect proliferation of most digestive tract cancer cells except pancreatic cancer cells. However, knockdown of LAP2 beta decreased motility of all tested cancer cells. Moreover, overexpression of LAP2 beta increased motility of gastric and pancreatic cancer cells. In the liver metastasis xenograft model, LAP2 beta increased metastatic efficacy of gastric cancer cells and mortality in tested mice. cDNA microarrays showed the possibility that myristoylated alanine-rich C kinase substrate (MARCKS) and interleukin6 (IL6) may mediate LAP2 beta-regulated motility of cancer cells. Conclusions: From the above results, we conclude that LAP2 is widely overexpressed in diverse digestive tract cancers and LAP2 beta regulates motility of cancer cells and suggest that LAP2 beta may have utility for diagnostics and therapeutics in digestive tract cancers.

Purpose: Computed tomography (CT) lymphography is a simple technique of sentinel node navigation but tissue reaction after injection of contrast media has not been reported yet. Methods: Ninety mice used in this study were divided into three groups: lipiodol, iopamidol, and normal saline. The test compounds were given by submucosal injection to the gastric wall of anesthetized mice. The specimens were subjected to histopathological examination. Results: The mean grades of acute inflammatory response after iopamidol and lipiodol injection were significantly higher than control group. However, there was no significant difference between iopamidol and lipiodol injection. The mean grade of chronic inflammatory response and fibrosis showed no differences between groups. The presence or absence of fibrinoid necrosis and mesothelial hyperplasia showed no statistical differences at each time point between groups. The foam cell, which is similar to human signet ring cell carcinoma, were not identified in normal saline and iopamidol group, but were detected by postoperative day 7 in lipiodol group. Conclusion: We conclude that iopamidol and lipiodol when used as a contrast media of CT lymphography is an available material for preoperative sentinel node navigation surgery for gastric cancer with an acceptable incidence of pathological alterations in a mouse model. Our results are potentially useful to clinical (human) application.