Comparing artificial intelligence to humans for endoscopic diagnosis of gastric neoplasia: An external validation study

OBJECTIVES

Artificial intelligence (AI) uses deep learning functionalities that may enhance the detection of early gastric cancer during endoscopy. An AI-based endoscopic system for upper endoscopy was recently developed in Japan. We aim to validate this AI-based system in a Singaporean cohort.

METHODS

There were 300 de-identified still images prepared from endoscopy video files obtained from subjects that underwent gastroscopy in National University Hospital (NUH). Five specialists and 6 non-specialists (trainees) from NUH were assigned to read and categorize the images into "neoplastic" or "non-neoplastic." Results were then compared with the readings performed by the endoscopic AI system.

RESULTS

The mean accuracy, sensitivity, and specificity for the 11 endoscopists were 0.847, 0.525, and 0.872, respectively. These values for the AI-based system were 0.777, 0.591, and 0.791, respectively. While AI in general did not perform better than endoscopists on the whole, in the subgroup of high-grade dysplastic lesions, only 29.1% were picked up by the endoscopist rating, but 80% were classified as neoplastic by AI (P = 0.0011). The average diagnostic time was also faster in AI compared with endoscopists (677.1 s vs 42.02 s (P < 0.001).

CONCLUSION

We demonstrated that an AI system developed in another health system was comparable in diagnostic accuracy in the evaluation of static images. AI systems are faster and not fatigable and may have a role in augmenting human diagnosis during endoscopy. With more advances in AI and larger studies to support its efficacy it would likely play a larger role in screening endoscopy in future.

A hydrogel-based mechanical metamaterial for the interferometric profiling of extracellular vesicles in patient samples

The utility of mechanical metamaterials for biomedical applications has seldom been explored. Here we show that a metamaterial that is mechanically responsive to antibody-mediated biorecognition can serve as an optical interferometric mask to molecularly profile extracellular vesicles in ascites fluid from patients with cancer. The metamaterial consists of a hydrogel responsive to temperature and redox activity functionalized with antibodies to surface biomarkers on extracellular vesicles, and is patterned into micrometric squares on a gold-coated glass substrate. Through plasmonic heating, the metamaterial is maintained in a transition state between a relaxed form and a buckled state. Binding of extracellular vesicles from the patient samples to the antibodies on the hydrogel causes it to undergo crosslinking, induced by free radicals generated via the activity of horseradish peroxidase conjugated to the antibodies. Hydrogel crosslinking causes the metamaterial to undergo fast chiral re-organization, inducing amplified changes in its mechanical deformation and diffraction patterns, which are detectable by a smartphone camera. The mechanical metamaterial may find broad utility in the sensitive optical immunodetection of biomolecules.

PIPAC nebulizer: How to test the new devices in the market, expert recommendations

Pressurized intraperitoneal aerosol chemotherapy, named PIPAC, is now used in many centers around the world and as an intraperitoneal drug delivery system for treatment of peritoneal carcinomatosis. Recently, many of us have encountered problems during PIPAC procedures due to changes in material and production features of the original PIPAC nebulizer. Concomitantly, new PIPAC nebulizers proposed by other manufacturers are being launched on the market; which claim that they are the same as the original device in delivering PIPAC. However, these new devices are all different in terms of materials, technical characteristics and costs. We have considered that, to maintain the acquired results of PIPAC, we must ensure that the new systems are equivalent. The characteristics deemed essential by the expert group are as follows: 1: The nebulizer must be able to create droplets through an injector pressure between 10 and 20 bars, 2: The mean droplet size must be 3 micrometers, with 95% of the droplets between 0 and 10 micrometers, 3: The diffusion angle must be 70 degrees, which is the minimum.

Outcomes of a Phase II Study of Intraperitoneal Paclitaxel plus Systemic Capecitabine and Oxaliplatin (XELOX) for Gastric Cancer with Peritoneal Metastases

BACKGROUND

Adding intraperitoneal paclitaxel (IP-PTX) to paclitaxel/5-fluoropyrimidine has shown promising results in patients with gastric cancer peritoneal metastases (GCPM) but has not been studied with standard-of-care platinum/fluoropyrimidine combinations. Our goal to was evaluate IP-PTX with capecitabine/oxaliplatin (XELOX) in GCPM.

METHODS

Forty-four patients with GCPM received IP PTX (40 mg/m², Days 1, 8), oral capecitabine (1000 mg/m² twice daily, Days 1-14) and intravenous oxaliplatin (100 mg/m², Day 1) in 21-day cycles. Patients with synchronous GCPM underwent conversion surgery if they had good response after chemotherapy, conversion to negative cytology, no extraperitoneal metastasis, and no peritoneal disease during surgery. The primary endpoint was overall survival and secondary endpoints were progression-free survival and safety. Outcomes from the trial were compared against a matched cohort of 39 GCPM patients who received systemic chemotherapy (SC) comprising platinum/fluoropyrimidine.

RESULTS

The median OS for the IP and SC groups was 14.6 and 10.6 months (hazard ratio [HR] 0.44; 95% confidence interval [CI], 0.26-0.74; p = 0.002). The median PFS for the IP and SC group was 9.5 and 4.4 months respectively (HR 0.39; 95% CI 0.25-0.66; p < 0.001). Patients in the SC group were younger (IP vs. SC, 61 vs. 56 years, p = 0.021) and had better performance status (ECOG 0, IP vs. SC, 47.7% vs. 76.9%, p = 0.007) compared with the IP cohort. In IP group, conversion surgery was performed in 36.1% (13/36) of patients, with a median OS of 24.2 (95% CI 13.1-35.3) months and 1-year OS of 84.6%.

CONCLUSIONS

IP PTX with XELOX is a promising treatment option for GCPM patients. In patients with good response, conversion surgery was feasible with favourable outcomes.

Academy of Medicine, Singapore clinical guideline on endoscopic surveillance and management of gastric premalignant lesions

Gastric cancer (GC) has a good prognosis, if detected at an early stage. The intestinal subtype of GC follows a stepwise progression to carcinoma, which is treatable with early detection and intervention using high-quality endoscopy. Premalignant lesions and gastric epithelial polyps are commonly encountered in clinical practice. Surveillance of patients with premalignant gastric lesions may aid in early diagnosis of GC, and thus improve chances of survival. An expert professional workgroup was formed to summarise the current evidence and provide recommendations on the management of patients with gastric premalignant lesions in Singapore. Twenty-five recommendations were made to address screening and surveillance, strategies for detection and management of gastric premalignant lesions, management of gastric epithelial polyps, and pathological reporting of gastric premalignant lesions.

Textbook outcome following oesophagectomy for cancer: international cohort study

Background

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

Methods

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

Results

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter ‘no major postoperative complication’ had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P &lt; 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P &lt; 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

Conclusion

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Textbook outcome following oesophagectomy for cancer: international cohort study

BACKGROUND

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

METHODS

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

RESULTS

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter 'no major postoperative complication' had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P < 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P < 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

CONCLUSION

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Coronavirus viability in surgical plume and methods for safe disposal: a preclinical model

Smoke generated by cautery devices used during surgery may contain infective particles and may cause transmission of airborne viruses. This study determines whether live viruses are present in surgical smoke and evaluates the effectiveness of several proposed methods of removal so as to improve safety of healthcare workers.

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND

The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting.

METHODS

Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups.

RESULTS

Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005).

CONCLUSION

Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery.

Surfactant-guided spatial assembly of nano-architectures for molecular profiling of extracellular vesicles

The controlled assembly of nanomaterials into desired architectures presents many opportunities; however, current preparations lack spatial precision and versatility in developing complex nano-architectures. Inspired by the amphiphilic nature of surfactants, we develop a facile approach to guide nanomaterial integration – spatial organization and distribution – in metal-organic frameworks (MOFs). Named surfactant tunable spatial architecture (STAR), the technology leverages the varied interactions of surfactants with nanoparticles and MOF constituents, respectively, to direct nanoparticle arrangement while molding the growing framework. By surfactant matching, the approach achieves not only tunable and precise integration of diverse nanomaterials in different MOF structures, but also fast and aqueous synthesis, in solution and on solid substrates. Employing the approach, we develop a dual-probe STAR that comprises peripheral working probes and central reference probes to achieve differential responsiveness to biomarkers. When applied for the direct profiling of clinical ascites, STAR reveals glycosylation signatures of extracellular vesicles and differentiates cancer patient prognosis.

Current methods for controlled assembly of nanomaterials into desired architectures often lack the precision and versatility to develop complex architectures. Here the authors report STAR, surfactant tunable spatial architecture, to guide nanomaterial integration in metal-organic frameworks.

PIPAC-OX: A Phase I Study of Oxaliplatin-Based Pressurized Intraperitoneal Aerosol Chemotherapy in Patients with Peritoneal Metastases

PURPOSE

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel laparoscopic, intraperitoneal chemotherapy delivery technique aiming to improve drug distribution and tissue penetration to treat peritoneal metastases. Thus far, PIPAC oxaliplatin is conducted at an arbitrary dose of 92 mg/m². We conducted a phase I study to establish safety and tolerability.

PATIENTS AND METHODS

We used a 3+3 dose-escalation design of PIPAC oxaliplatin for patients with peritoneal metastases from gastrointestinal tumors, after failure of at least first-line chemotherapy. Dose levels were planned at 45, 60, 90, and 120 mg/m².

RESULTS

This study included 16 patients with 24 PIPAC procedures (8 gastric; 5 colorectal; and 1 gallbladder, pancreas, and appendix cancer each). Median age and peritoneal cancer index (PCI) score were 62 years and 17, respectively. Two patients developed pancreatitis (grade 2 and 3) at 45 mg/m², necessitating cohort expansion. Another patient developed grade 2 pancreatitis at 90 mg/m². There were no other dose-limiting toxicities, and the highest-dose cohort (120 mg/m²) tolerated PIPAC well. Pharmacokinetic analyses demonstrated good linearity between dose and maximum concentration (r ² = 0.95) and AUC (r ² = 0.99). On the basis of RECIST, 62.5% and 50% had stable disease after one and two PIPAC procedures, respectively. A total of 8 patients underwent two PIPAC procedures, with improvement of median PCI and peritoneal regression grade score from 15 to 12 and 2.5 to 2.0, respectively.

CONCLUSIONS

The recommended phase II dose is 120 mg/m². Future studies should further delineate the efficacy and role of PIPAC oxaliplatin for peritoneal metastases.See related commentary by de Jong et al., p. 1830.

Evaluating the Use of microRNA Blood Tests for Gastric Cancer Screening in a Stratified Population-Level Screening Program: An Early Model-Based Cost-Effectiveness Analysis

OBJECTIVES

To evaluate cost-effectiveness of a novel screening strategy using a microRNA (miRNA) blood test as a screen, followed by endoscopy for diagnosis confirmation in a 3-yearly population screening program for gastric cancer.

METHODS

A Markov cohort model has been developed in Microsoft Excel 2016 for the population identified to be at intermediate risk (Singaporean men, aged 50-75 years with Chinese ethnicity). The interventions compared were (1) initial screening using miRNA test followed by endoscopy for test-positive individuals and a 3-yearly follow-up screening for test-negative individuals (proposed strategy), and (2) no screening with gastric cancer being diagnosed clinically (current practice). The model was evaluated for 25 years with a healthcare perspective and accounted for test characteristics, compliance, disease progression, cancer recurrence, costs, utilities, and mortality. The outcomes measured included incremental cost-effectiveness ratios, cancer stage at diagnosis, and thresholds for significant variables.

RESULTS

The miRNA-based screening was found to be cost-effective with an incremental cost-effectiveness ratio of $40 971/quality-adjusted life-year. Key drivers included test costs, test accuracy, cancer incidence, and recurrence risk. Threshold analysis highlights the need for high accuracy of miRNA tests (threshold sensitivity: 68%; threshold specificity: 77%). A perfect compliance to screening would double the cancer diagnosis in early stages compared to the current practice. Probabilistic sensitivity analysis reported the miRNA-based screening to be cost-effective in >95% of iterations for a willingness to pay of $70 000/quality-adjusted life-year (approximately equivalent to 1 gross domestic product/capita) CONCLUSIONS: The miRNA-based screening intervention was found to be cost-effective and is expected to contribute immensely in early diagnosis of cancer by improving screening compliance.

ELSA recommendations for minimally invasive surgery during a community spread pandemic: a centered approach in Asia from widespread to recovery phases

BACKGROUND

The COVID-19 pandemic has resulted in significant changes to surgical practice across the worlds. Some countries are seeing a tailing down of cases, while others are still having persistent and sustained community spread. These evolving disease patterns call for a customized and dynamic approach to the selection, screening, planning, and for the conduct of surgery for these patients.

METHODS

The current literature and various international society guidelines were reviewed and a set of recommendations were drafted. These were circulated to the Governors of the Endoscopic and Laparoscopic Surgeons of Asia (ELSA) for expert comments and discussion. The results of these were compiled and are presented in this paper.

RESULTS

The recommendations include guidance for selection and screening of patients in times of active community spread, limited community spread, during times of sporadic cases or recovery and the transition between phases. Personal protective equipment requirements are also reviewed for each phase as minimum requirements. Capability management for the re-opening of services is also discussed. The choice between open and laparoscopic surgery is patient based, and the relative advantages of laparoscopic surgery with regard to complications, and respiratory recovery after major surgery has to be weighed against the lack of safety data for laparoscopic surgery in COVID-19 positive patients. We provide recommendations on the operating room set up and conduct of general surgery. If laparoscopic surgery is to be performed, we describe circuit modifications to assist in reducing plume generation and aerosolization.

CONCLUSION

The COVID-19 pandemic requires every surgical unit to have clear guidelines to ensure both patient and staff safety. These guidelines may assist in providing guidance to units developing their own protocols. A judicious approach must be adopted as surgical units look to re-open services as the pandemic evolves.

Cutaneous port-site recurrence secondary to tumour seeding following implantation of an intraperitoneal chemotherapy access port for gastric cancer

Intraperitoneal chemotherapy has shown promising results for the treatment of peritoneal carcinomatosis in gastric cancer. However, the implantation of an intraperitoneal chemotherapy port may be associated with catheter-related complications. The authors describe a case of cutaneous port-site recurrence secondary to tumour seeding from an intraperitoneal chemotherapy access port.

Exosome-templated nanoplasmonics for multiparametric molecular profiling

Exosomes are nanoscale vesicles distinguished by characteristic biophysical and biomolecular features; current analytical approaches, however, remain univariate. Here, we develop a dedicated platform for multiparametric exosome analysis-through simultaneous biophysical and biomolecular evaluation of the same vesicles-directly in clinical biofluids. Termed templated plasmonics for exosomes, the technology leverages in situ growth of gold nanoshells on vesicles to achieve multiselectivity. For biophysical selectivity, the nanoshell formation is templated by and tuned to distinguish exosome dimensions. For biomolecular selectivity, the nanoshell plasmonics locally quenches fluorescent probes only if they are target-bound on the same vesicle. The technology thus achieves multiplexed analysis of diverse exosomal biomarkers (e.g., proteins and microRNAs) but remains unresponsive to nonvesicle biomarkers. When implemented on a microfluidic, smartphone-based sensor, the platform is rapid, sensitive, and wash-free. It not only distinguished biomarker organizational states in native clinical samples but also showed that the exosomal subpopulation could more accurately differentiate patient prognosis.

Recent Advances in Intra-peritoneal Chemotherapy for Gastric Cancer

Peritoneal metastasis (PM) frequently occurs in patients with gastric cancer (GC) and confers a dismal prognosis despite advances in systemic chemotherapy. While systemic chemotherapy has poor peritoneal penetration, intraperitoneal (IP) chemotherapy remains sequestered, resulting in high peritoneal drug concentrations with less systemic side-effects. The first application of IP treatment was hyperthermic intraperitoneal chemotherapy (HIPEC) with cytoreductive surgery (CRS) for gastric cancer peritoneal metastasis (GCPM); but was associated with an increased morbidity and mortality rate without significantly improving overall survival (OS). While CRS confers limited benefit, the potential role of prophylactic HIPEC and laparoscopic neoadjuvant HIPEC are currently being evaluated. Combination systemic and IP chemotherapy (SIPC) gained popularity in the 1990s, since it provided the benefits of IP treatment while reducing surgical morbidity, demonstrating promising early results in multiple Phase II trials. Unfortunately, these findings were not confirmed in the recent PHOENIX-GC randomized controlled trial; therefore, the appropriate treatment for GCPM remains controversial. Small observational studies from Japan and Singapore have reported successful downstaging of PM in GC patients receiving SIPC who subsequently underwent conversion gastrectomy with a median OS of 21.6–34.6 months. Recently, the most significant development in IP-directed therapy is pressurized IP aerosol chemotherapy (PIPAC). Given that aerosol chemotherapy achieves a wider distribution and deeper penetration, the outcomes of multiple ongoing trials assessing its efficacy are eagerly awaited. Indeed, IP-directed therapy has evolved rapidly in the last 3 decades, with an encouraging trend toward improved outcomes in GCPM, and may offer some hope for an otherwise fatal disease.

Kamikawa Double-Flap Reconstruction After Minimally Invasive Ivor-Lewis Esophagectomy

Despite the high incidence of reflux esophagitis, there are few reports of antireflux modifications for minimally invasive Ivor-Lewis esophagectomy. We present the case of a 63-year-old man with mid-thoracic esophageal squamous cell carcinoma who underwent minimally invasive Ivor-Lewis esophagectomy after neoadjuvant chemoradiotherapy. Laparoscopic dissection, gastric tube creation, and mobilization was performed. Thoracoscopic esophageal dissection, subcarinal, paraesophageal and diaphragmatic lymphadenectomy were performed, followed by esophagogastric anastomosis with double seromuscular flap reconstruction to recreate the lower esophageal sphincter. The operation was completed in 618 minutes with 200 mL blood loss and the patient recovered uneventfully. A morphologic sphincter was seen on postoperative contrast study.

Sleeve Gastrectomy and Roux-En-Y Gastric Bypass Lead to Comparable Changes in Body Composition in a Multiethnic Asian Population

BACKGROUND

Changes in body composition after bariatric surgery such as a sustained loss of body fat are often associated with an inevitable loss of fat free mass. This can contribute to an undesirable disturbance in resting metabolic rate and weight maintenance. Our aim was to study changes in body composition in a multiethnic Asian cohort following bariatric surgery and to identify differences between laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass.

METHODS

A retrospective review of prospectively collected data on 295 patients who underwent either laparoscopic sleeve gastrectomy (256 patients) or laparoscopic Roux-en-Y gastric bypass (39 patients) was performed. Body composition variables were measured with the analyzer, GAIA 359 PLUS, which included the parameters; total body weight, body mass index, excess weight, basal metabolic rate, fat-free mass, fat mass, and total body water.

RESULTS

There were no statistical differences in gender, ethnicity, age, weight, height, and body mass index between laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass. At each time point (6, 12, 24, and 36 months) post-operation, there was no significant differences in % total body weight loss, basal metabolic rate, fat mass, fat percentage, and total body water between sleeve gastrectomy and bypass patients. There was significant difference (p < 0.05) in fat free mass only at 3 years post-operation, with sleeve gastrectomy patients having 9.79 kg less fat-free mass than bypass patients. However, after multivariate analysis, we found no statistically significant differences.

CONCLUSION

Sleeve gastrectomy and gastric bypass seemed to give similar changes to body composition.

Palliative radiotherapy in symptomatic locally advanced gastric cancer: A phase II trial

To evaluate the response and quality of life of palliative gastric radiotherapy in patients with symptomatic locally advanced gastric cancer. Patients with bleeding, pain or obstruction and were treated with palliative gastric radiotherapy to a dose of 36 Gy in 12 daily fractions. The primary outcomes were symptom response rates. Secondary outcomes included overall survival, adverse events and proportion of patients with ≥10‐point absolute improvement in the fatigue, nausea/vomiting and pain subscales in the EORTC Qualify of Life Questionnaire C30 (EORTC QLQ‐C30) and dysphagia/pain subscales in the gastric specific module (STO22) at the end of RT and 1 month after the completion of radiotherapy. Fifty patients were accrued. Median survival duration was 85 days. 40/50 patients (80%) with bleeding, 2/2 (100%) patients with obstruction and 1/1 (100%) patient with pain responded to radiotherapy. Improvements fatigue, nausea/vomiting and pain subscales of the EORTC QLQ‐C30 was seen in 50%, 28% and 44% of patients at the end of RT and in 63%, 31% and 50% of patients 1 month after RT. Improvements in dysphagia/pain subscales of the STO22 was seen in 42% and 28% of patients at then end of RT and 44% and 19% of patients 1 month after RT. Two patients (5%) had grade 3 anorexia and gastritis. Palliative gastric radiotherapy was effective, well tolerated and resulted in improvement in fatigue, dysphagia and pain at the end of radiotherapy and 1 month after the completion of radiotherapy in a significant proportion of patients.

Gelsolin-mediated activation of PI3K/Akt pathway is crucial for hepatocyte growth factor-induced cell scattering in gastric carcinoma

In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC.

Recurrent Fusion Genes in Gastric Cancer: CLDN18-ARHGAP26 Induces Loss of Epithelial Integrity

Genome rearrangements, a hallmark of cancer, can result in gene fusions with oncogenic properties. Using DNA paired-end-tag (DNA-PET) whole-genome sequencing, we analyzed 15 gastric cancers (GCs) from Southeast Asians. Rearrangements were enriched in open chromatin and shaped by chromatin structure. We identified seven rearrangement hot spots and 136 gene fusions. In three out of 100 GC cases, we found recurrent fusions between CLDN18, a tight junction gene, and ARHGAP26, a gene encoding a RHOA inhibitor. Epithelial cell lines expressing CLDN18-ARHGAP26 displayed a dramatic loss of epithelial phenotype and long protrusions indicative of epithelial-mesenchymal transition (EMT). Fusion-positive cell lines showed impaired barrier properties, reduced cell-cell and cell-extracellular matrix adhesion, retarded wound healing, and inhibition of RHOA. Gain of invasion was seen in cancer cell lines expressing the fusion. Thus, CLDN18-ARHGAP26 mediates epithelial disintegration, possibly leading to stomach H(+) leakage, and the fusion might contribute to invasiveness once a cell is transformed.

CT volumetry for gastric carcinoma: association with TNM stage

OBJECTIVES

We evaluated the feasibility of performing CT volumetry of gastric carcinoma (GC) and its correlation with TNM stage.

METHODS

This institutional review board-approved retrospective study was performed on 153 patients who underwent a staging CT study for histologically confirmed GC. CT volumetry was performed by drawing regions of interest including abnormal thickening of the stomach wall. Reproducibility of tumour volume (Tvol) between two readers was assessed. Correlation between Tvol and TNM/peritoneal staging derived from histology/surgical findings was evaluated using ROC analysis and compared with CT evaluation of TNM/peritoneal staging.

RESULTS

Tvol was successfully performed in all patients. Reproducibility among readers was excellent (r = 0.97; P = 0.0001). The median Tvol of GC showed an incremental trend with T-stage (T1 = 27 ml; T2 = 32 ml; T3 = 53 ml and T4 = 121 ml, P < 0.01). Tvol predicted with good accuracy T-stage (≥T2:0.95; ≥T3:0.89 and T4:0.83, P = 0.0001), M-stage (0.87, P = 0.0001), peritoneal metastases (0.87, P = 0.0001) and final stage (≥stage 2:0.89; ≥stage 3:0.86 and stage 4:0.87, P = 0.0001), with moderate accuracy for N-stage (≥N1:0.75; ≥N2:0.74 and N3:0.75, P = 0.0001). Tvol was significantly (P < 0.05) more accurate than standard CT staging for prediction of T-stage, N3-stage, M-stage and peritoneal metastases.

CONCLUSION

CT volumetry may provide useful adjunct information for preoperative staging of GC.

KEY POINTS

CT volumetry of gastric carcinoma is feasible and reproducible. Tumour volume <19.4 ml predicts T1-stage gastric cancer with 91% sensitivity and 100% specificity (P = 0.0001). Tumour volume >95.7 ml predicts metastatic gastric cancer with 87% sensitivity and 78.5% specificity (P = 0.0001). CT volumetry may be a useful adjunct for staging gastric carcinoma.

Bariatric surgery in Singapore from 2005 to 2009

INTRODUCTION

Obesity is a major public health concern worldwide, including Singapore. Bariatric surgery has grown in popularity to combat this situation, and innovations in this field have led to the emergence of new bariatric procedures. For the healthy growth of this specialized field of surgery, it is mandatory to audit the progress and state of bariatric surgery at regular intervals.

METHODS

An e-mail questionnaire survey was conducted in all the leading hospitals of Singapore practicing bariatric surgery between 2005 and 2009. All four hospitals to which the questionnaire survey was mailed responded. The responses from these hospitals were tabulated and analyzed.

RESULTS

Between 2005 and 2009, a total of 278 bariatric procedures were performed on 151 men and 127 women with a mean age of 40.34 years (range: 18-64 years) by 12 practicing surgeons. The mean body mass index was 42.25 kg/m(2) (range: 31.4-73 kg/m(2)). All the operations were performed laparoscopically. The most commonly performed procedure was adjustable gastric banding (81.65%), followed by sleeve gastrectomy (13.66%) and Roux en Y gastric bypass (3.95%).

CONCLUSION

There is a flux of newer procedures in Singapore. Adjustable gastric banding, which was the only available procedure being performed in 2004, was gradually being replaced by other procedures such as sleeve gastrectomy and Roux-en-Y gastric bypass in 2009.

Whole-genome reconstruction and mutational signatures in gastric cancer

Background

Gastric cancer is the second highest cause of global cancer mortality. To explore the complete repertoire of somatic alterations in gastric cancer, we combined massively parallel short read and DNA paired-end tag sequencing to present the first whole-genome analysis of two gastric adenocarcinomas, one with chromosomal instability and the other with microsatellite instability.

Results

Integrative analysis and de novo assemblies revealed the architecture of a wild-type KRAS amplification, a common driver event in gastric cancer. We discovered three distinct mutational signatures in gastric cancer - against a genome-wide backdrop of oxidative and microsatellite instability-related mutational signatures, we identified the first exome-specific mutational signature. Further characterization of the impact of these signatures by combining sequencing data from 40 complete gastric cancer exomes and targeted screening of an additional 94 independent gastric tumors uncovered ACVR2A, RPL22 and LMAN1 as recurrently mutated genes in microsatellite instability-positive gastric cancer and PAPPA as a recurrently mutated gene in TP53 wild-type gastric cancer.

Conclusions

These results highlight how whole-genome cancer sequencing can uncover information relevant to tissue-specific carcinogenesis that would otherwise be missed from exome-sequencing data.

Validation of the functional assessment of cancer therapy-gastric module for the Chinese population

Background

Quality of life (QoL) assessment has become an important aspect of the clinical management of gastric cancer (GC), which poses a greater health threat in Chinese populations around the world. Functional Assessment of Cancer Therapy-Gastric Module (FACT-Ga), a questionnaire developed specifically to measure QoL of patients with GC, has never been validated in Chinese subjects. The current study was designed to examine the psychometric properties of FACT-Ga as a GC specific QoL instrument for its future use in Chinese populations.

Methods

A sample of 67 Chinese patients with GC in the National University Hospital, Singapore was investigated cross-sectionally. The participants independently completed either English or Chinese versions of the FACT-Ga and the European Quality of Life-5 Dimensions (EQ-5D). Reliability was measured as the Cronbach’s α for EQ-5D, and five subscale scores and two total scores of FACT-Ga. The sensitivity to patients’ clinical status was evaluated by comparing EQ-5D and FACT-Ga scores between clinical subgroups classified by Clinical Stage and Treatment Intent. The construct validity of FACT-Ga was assessed internally by examining the item-to-scale correlations and externally by contrasting the FACT-Ga subscales with the EQ-5D domains.

Results

For both FACT-Ga and EQ-5D, patients treated with curative intent rated their QoL higher than those treated for palliation, and early stage patients scored higher than those in the late stage. The sensitivity to clinical status of FACT-Ga scores were differential as four of seven FACT-Ga scores were significant for Treatment Intent while only one subscale score was significant for Clinical Stage. Six FACT-Ga scores had Cronbach’s α of 0.8 or above indicating excellent reliability. For construct validity, 45 of 46 items converged about their respective subscales. The monotrait-multimethod correlations between QoL constructs of FACT-Ga and EQ-5D were stronger than the multitrait-multimethod correlations as theoretically hypothesized, suggesting good convergent and discriminant validities.

Conclusions

Given the excellent reliability and good construct validity, FACT-Ga scores are able to distinguish patient groups with different clinical characteristics in the expected direction. Therefore FACT-Ga can be used as a discriminative instrument for measuring QoL of Chinese patients with GC.

Bariatric surgery in Asia in the last 5 years (2005-2009)

Obesity is a major public health concern around the world, including Asia. Bariatric surgery has grown in popularity to combat this rising trend. An e-mail questionnaire survey was sent to all the representative Asia-Pacific Metabolic and Bariatric Surgery Society (APMBSS) members of 12 leading Asian countries to provide bariatric surgery data for the last 5 years (2005-2009). The data provided by representative members were discussed at the 6th International APMBSS Congress held at Singapore between 21st and 23rd October 2010. Eleven nations except China responded. Between 2005 and 2009, a total of 6,598 bariatric procedures were performed on 2,445 men and 4,153 women with a mean age of 35.5 years (range, 18-69years) and mean BMI of 44.27 kg/m(2) (range, 31.4-73 kg/m(2)) by 155 practicing surgeons. Almost all of the operations were performed laparoscopically (99.8%). For combined years 2005-2009, the four most commonly performed procedures were laparoscopic adjustable gastric banding (LAGB, 35.9%), laparoscopic standard Roux-en-Y gastric bypass (LRYGB, 24.3%), laparoscopic sleeve gastrectomy (LSG, 19.5%), and laparoscopic mini gastric bypass (15.4%). Comparing the 5-year trend from 2004 to 2009, the absolute numbers of bariatric surgery procedures in Asia increased from 381 to 2,091, an increase of 5.5 times. LSG increased from 1% to 24.8% and LRYGB from 12% to 27.7%, a relative increase of 24.8 and 2.3 times, whereas LAGB and mini gastric bypass decreased from 44.6% to 35.6% and 41.7% to 6.7%, respectively. The absolute growth rate of bariatric surgery in Asia over the last 5 years was 449%.

Cancer of the gastric cardia is rising in incidence in an Asian population and is associated with adverse outcome

BACKGROUND

Tumors arising from the esophagogastric junction (OGJ) are increasing in incidence in the west, but data from Asian populations are conflicting. Singapore has a mixed-Asian population with an international lifestyle. This study was designed to examine the changing trends in incidence of gastric cardia cancer (type III) within this population and to compare the clinicopathological characteristics and outcome of these tumors with gastric tumors.

METHODS

Trends in cancer incidence were obtained from the Singapore Cancer Registry. Clinicopathological data were prospectively collected from patients undergoing surgery for gastric cancer who presented to the National University Hospital between 2000 and 2005. Patients underwent surgery with or without (neo)adjuvant therapy. Survival duration was analyzed.

RESULTS

The incidence of cardia tumors has increased each decade since 1968 (1968-1982, 6.3%; 1983-1992, 7.6%; 1993-1997, 8.4%; 1998-2002, 9.1%; 2003-2007, 16.2%). Among the study population (n = 159) cardia tumors were associated with male sex (p < 0.01) and dysphagia (p < 0.01). Although R0 resection rates were similar, systemic recurrence rates were higher among patients with cardia cancer (p = 0.031) and survival was reduced compared with patients with non-cardia gastric cancer (median survival 26 vs. 69 months; p < 0.001). Cardia location of the tumor and metastatic lymph node ratio were identified as independent adverse prognostic indicators on multivariate analysis.

CONCLUSIONS

Similar to western societies, the incidence of proximal gastric cancer is increasing in Singapore. Cardia tumors are associated with poorer outcomes, suggesting that cardia cancer is a distinct disease from true gastric cancer requiring different management strategies to improve the outcome for these patients.

Experienced versus inexperienced confocal endoscopists in the diagnosis of gastric adenocarcinoma and intestinal metaplasia on confocal images

BACKGROUND

Confocal laser endomicroscopy (CLE) may be used to diagnose gastric cancer and intestinal metaplasia, but the impact of CLE experience on the accuracy of confocal diagnosis of gastric cancer and intestinal metaplasia is not clear.

OBJECTIVE

To establish the sensitivity, specificity, and intragroup interobserver agreement of CLE image interpretation by 3 experienced (group 1) and 3 inexperienced (group 2) CLE endoscopists for diagnosing gastric intestinal metaplasia (GIM) and adenocarcinoma.

DESIGN

Blinded review of CLE images for the diagnosis of gastric cancer or intestinal metaplasia.

SETTING

Tertiary care hospital.

PATIENTS

CLE images obtained ex vivo from gastrectomy specimens with proven gastric cancer and CLE images obtained in vivo from Chinese subjects older than 50 years of age by using matched biopsy specimens as reference standards.

MAIN OUTCOME MEASUREMENTS

Sensitivity, specificity, and intragroup interobserver agreement of CLE image interpretation.

RESULTS

Interpretation of in vivo images by group 1 was associated with higher sensitivity (95.2% vs 61.9%, P = .039) and higher specificity (93.3% vs 62.2%, P < .001) for GIM than interpretation by group 2. The agreement between interpretation by group 1 and histology for GIM was higher than that for group 2 (κ = 0.864 vs 0.217). The sensitivity (93.3% for group 1 vs 86.7% for group 2, P = 1.000) and specificity (87.7% for group 1 vs 80.7% for group 2, P = .344) of interpretation of ex vivo CLE images for the diagnosis of gastric adenocarcinoma was similar for groups 1 and 2.

LIMITATIONS

Single-center study.

CONCLUSIONS

Experience in CLE was associated with greater accuracy in the diagnosis of intestinal metaplasia.

Comprehensive long-span paired-end-tag mapping reveals characteristic patterns of structural variations in epithelial cancer genomes

Somatic genome rearrangements are thought to play important roles in cancer development. We optimized a long-span paired-end-tag (PET) sequencing approach using 10-Kb genomic DNA inserts to study human genome structural variations (SVs). The use of a 10-Kb insert size allows the identification of breakpoints within repetitive or homology-containing regions of a few kilobases in size and results in a higher physical coverage compared with small insert libraries with the same sequencing effort. We have applied this approach to comprehensively characterize the SVs of 15 cancer and two noncancer genomes and used a filtering approach to strongly enrich for somatic SVs in the cancer genomes. Our analyses revealed that most inversions, deletions, and insertions are germ-line SVs, whereas tandem duplications, unpaired inversions, interchromosomal translocations, and complex rearrangements are over-represented among somatic rearrangements in cancer genomes. We demonstrate that the quantitative and connective nature of DNA-PET data is precise in delineating the genealogy of complex rearrangement events, we observe signatures that are compatible with breakage-fusion-bridge cycles, and we discover that large duplications are among the initial rearrangements that trigger genome instability for extensive amplification in epithelial cancers.

Laparoscopic appendectomy by residents: evaluating outcomes and learning curve

BACKGROUND

Laparoscopic appendectomy is being performed increasingly, worldwide. To the resident, it provides a valuable opportunity to master basic laparoscopic skills. Studies have shown that laparoscopic appendectomy performed by residents is safe. However, to date, there is no clear evidence for the minimum number of these operations required to achieving proficiency and safety. The aim of this study is to assess the outcome of laparoscopic appendectomies performed by surgical residents and to evaluate the effect of learning curve on patient outcome.

METHODS

All patients undergoing laparoscopic appendectomies performed by six residents during the study period were reviewed. Data on patient demographics,clinical and histological diagnosis, and outcome variables including operative duration, conversion to open surgery, complications, and length of stay were analyzed. We evaluated the effect of the learning curve by dividing patients into two groups: a first group consisting of the initial 20 patients and a second group consisting of the next 20 patients operated upon independently by each resident. Variables were analyzed to determine any difference between the two groups.

RESULTS

Three hundred six patients with the clinical diagnosis of acute appendicitis underwent laparoscopic appendectomy by residents. Mean operative time was 83.8 min. Of patients, 14.6% required conversion to open surgery. Mean length of hospitalization was 2.82 days. Operative duration and complication rate were significantly reduced with increasing experience of residents. The length of hospital stay and conversion rate to open surgery remained unchanged.

CONCLUSION

Operative duration and complications can be reduced with increasing experience of a resident.

Surgical management of obesity - National University Hospital experience

INTRODUCTION

The Singapore National Survey of 2004 reported the prevalence of obesity to have increased to 6.9%, thus reflecting the profound changes in our society's lifestyle and eating habits. Bariatric surgery has steadily been increasing to counter the ill effects of obesity.

MATERIALS AND METHODS

We audited our prospective series of 31 patients who had laparoscopic adjustable gastric banding (LABG) for morbid obesity performed by our multidisciplinary team at the National University Hospital, Singapore, between August 2004 and December 2006.

RESULTS

The median age at presentation was 40 years old including 6 males and 25 females. Their median BMI was 42.35 kg/m(2). At a median follow-up of 26 months, the median percentage of excess weight loss (%EWL) was 41.95%. The positive impact of gastric banding on comorbidities are evident whereby 15 (94%) of the diabetics had improved glycaemic control with HbA(1)C of 7.7% preoperatively improving to 5.9% postoperatively, and also 8 (58%) now take smaller doses of oral hypoglycaemic agents. Hypertension improved in 4 patients and 2 (11%) were cured. All our patients with dyslipidaemia had their statin doses reduced with marked lowering of serum lipid levels. We had 2 patients (6.45%) with band erosion and another 2 with reflux oesophagitis. Our article also summarises the available surgical procedures while discussing the pros and cons of each.

CONCLUSION

Our results showed that a multidisciplinary programme can achieve significant weight loss for obese patients in Singapore. To achieve long-term weight loss, a commitment of both the medical team and the patient is necessary. Laparoscopy has revolutionised the practice of bariatric surgery worldwide. LAGB is an effective and safe procedure.

Gastric adenocarcinoma occurring in a young patient with common variable immunodeficiency syndrome

Patients with common variable immunodeficiency syndrome (CVID) have an increased risk of gastric adenocarcinoma. We describe a case of gastric adenocarcinoma in a 29-year-old man with CVID. He complained of dyspepsia and weight loss. Endoscopy showed an antral lesion. He underwent subtotal gastrectomy with postoperative adjuvant chemoradiation, and remained disease-free for three years. CVID is a predisposing factor for gastric adenocarcinoma. Gastric complaints are common among these patients and should be viewed seriously. Endoscopy is performed to detect any pathology. Premalignant conditions like chronic atrophic gastritis, intestinal metaplasia and dysplasia require regular endoscopic surveillance in these high-risk patients.

Total transvaginal endoscopic abdominal wall hernia repair: a NOTES survival study

HYPOTHESIS

Natural orifice transluminal endoscopic surgery (NOTES) has gained widespread interest as a potentially less invasive alternative to laparoscopic surgery or, else, an evolution as the next-generation surgery. The main objective of this study was to assess the safety of transluminal abdominal wall hernia repair for potential human application by specifically investigating the feasibility and challenges of using a transvaginal approach.

DESIGN

NOTES ventral hernia repair via a transvaginal approach.

SETTING

University Hospital (National University Health System, Singapore).

PARTICIPANTS

The study utilized five female pigs (30-40 kg) between 5 and 7 months of age, which underwent abdominal wall hernia repair using a transvaginal approach.

INTERVENTION

The procedures were performed using a double-channel endoscope under general endotracheal anesthesia. A mesh was placed and fixed to the abdominal wall using standard laparoscopic and endoscopic equipment. The animals survived for 2 weeks and were then euthanized and a necropsy performed.

MAIN OUTCOME MEASURES

To assess the safety and feasibility of NOTES ventral hernia repair in a survival experimental model.

RESULTS

All of the procedures could be safely performed using the standard equipment. At the necropsy, all meshes were well in place and mild adhesions were recorded in one animal with a small abscess in the subcutaneous area.

CONCLUSION

This novel approach seems technically challenging but feasible using equipment and accessories currently available for conventional laparoscopic and interventional endoscopy with low intra-abdominal contamination and sepsis. New procedure-specific instruments and equipment need to be developed to allow the surgeon safer access and more degrees of instrument freedom.

Diagnostic laparoscopy in the evaluation of right lower abdominal pain: a one-year audit

INTRODUCTION

Acute appendicitis is the commonest cause for right lower abdominal pain. Clinical features, laboratory and imaging investigations are either not very sensitive or specific, and neither is therapeutic. We aimed to define the role of diagnostic laparoscopy in patients with right lower abdominal pain.

METHODS

Data was collected retrospectively from January 1, 2005 to December 31, 2005. Patients admitted to the Emergency Department and subsequently transferred to the Department of Surgery, National University Hospital, Singapore, with right lower abdominal pain and who eventually underwent diagnostic laparoscopy were evaluated.

RESULTS

691 patients with right lower abdominal pain were admitted with suspected diagnosis of appendicitis. Diagnostic laparoscopy was undertaken in 103 patients aged 17-71 years old. Of the 83 females, 78 (94 percent) were premenopausal . Histology-proven acute appendicitis was diagnosed in 78 (75.7 percent) patients. Interestingly, within this group, 25.6 percent had other concomitant pathologies found on laparoscopy. 25 patients had a normal appendix; gynaecological causes accounted for pain in 15 of these 25 (60 percent) cases. In four (3.9 percent) patients, no pathology was found. Complication rate was 1.9 percent, which included ileus in two patients. In 32 (31.1 percent) patients, diagnostic laparoscopy altered the management plan, requiring either intervention or care by a subspecialty.

CONCLUSION

Diagnostic laparoscopy is useful in evaluating patients with right lower abdominal pain, especially in those with equivocal signs of acute appendicitis. It also has the additional benefit of being therapeutic. Premenopausal women benefit the most from this procedure.

Endoscopic screening for gastric cancer

BACKGROUND & AIMS

Population endoscopic screening for gastric cancer is generally deemed not to be cost-effective except in Japan, where its prevalence is very high. However, in the absence of screening, patients present with advanced disease, and prognosis is poor. We conducted a cost utility analysis to determine whether endoscopic screening for stomach cancer in intermediate-risk population would be cost-effective and to better define the high-risk groups in the population who would benefit from such strategy.

METHODS

Cost-effectiveness analysis was performed by using a Markov Model. Simulation was performed on Singapore (intermediate-risk) population and various high-risk subgroups. Comparison was made between 2-yearly endoscopic mass screening program versus no screening. Data sources were extracted from relevant studies published from 1980-2004 identified via systematic PUBMED search. Main outcome measures were deaths caused by stomach cancer averted, cost per life saved, and incremental cost-effectiveness ratio expressed as cost per quality-adjusted life year (QALY) saved.

RESULTS

Screening of high-risk group of Chinese men (age-standardized rate, 25.9/100,000) from 50-70 years old is highly cost-effective, with cost benefit of United States $26,836 per QALY. Screening this cohort of 199,000 subjects prevents 743 stomach cancer deaths and saves 8234 absolute life years. Cost of averting 1 cancer death is United States $247,600. Cost-effectiveness was most sensitive to incidence of stomach cancer and cost of screening endoscopy.

CONCLUSIONS

Screening of stomach cancer in moderate to high-risk population subgroups is cost-effective. Targeted screening strategies for stomach cancer should be explored.

Detection of telomerase activity in gastric lavage fluid: a novel method to detect gastric cancer

BACKGROUND

Telomerase is a ribonucleoprotein polymerase that is essential for cell immortality. Recent studies have demonstrated that a high percentage of gastric cancer tissue expressed telomerase. This study describes the presence of telomerase activity in gastric lavage fluid in patients with gastric cancer.

METHODS

Gastric lavage fluid was collected during esophageogastroduodenoscopy in 70 patients: 25 with gastric cancer, 25 with peptic ulcer disease, and 20 with normal stomach. The fluid and biopsy samples were analyzed for telomerase activity by a polymerase chain reaction-based telomerase repeat amplification protocol. The findings were related to the histological results.

RESULTS

Telomerase activity was present in 24 of the 25 (96%) gastric cancer tissue and in 7 of the 25 tissue specimens from peptic ulcer or gastritis. In the gastric lavage fluid, telomerase was detected in 20 patients (80%) with gastric cancer, 7 patients (28%) with peptic ulcer, and none in normal subjects (P < 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value of gastric fluid telomerase expression in gastric cancer patients was 80%, 84%, 74%, and 88%, respectively.

CONCLUSIONS

The presence of telomerase activity is present in gastric lavage fluid of patients with gastric cancer as compared to those without, may represent a novel method for diagnosis of gastric cancer.