November 23, 2009
Study Highlights From November Issue Of GIE: Gastrointestinal Endoscopy
In the November issue of GIE: Gastrointestinal Endoscopy, the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE), a study out of Stanford University found that Barrett's esophagus was detected in six percent of asymptomatic women undergoing endoscopic screening. Also in this issue, two studies examined endoscopic ultrasound (EUS): Researchers from France, in the largest single-center experience to date, demonstrated the accuracy of EUS-FNA (fine needle aspiration) in diagnosing and determining the malignant behavior of pancreatic endocrine tumors; and a U.S. study found EUS and EUS-FNA in pediatric patients to be feasible, safe and have a significant impact on pediatric gastrointestinal, pancreatobiliary and mediastinal diseases.
"Screening for Barrett's esophagus in asymptomatic women"Barrett's esophagus is a condition where the lining of the esophagus changes due to chronic inflammation, generally from gastroesophageal reflux disease (GERD). Barrett's esophagus is important to recognize as it may increase the risk of developing esophageal cancer. It has been detected in approximately 10 percent of patients with GERD, but previous studies have demonstrated a similar prevalence of Barrett's esophagus in asymptomatic adults. The majority of patients found to have asymptomatic Barrett's esophagus in previous studies were male and white.
Whether asymptomatic Barrett's esophagus occurs in women has not been well studied. Researchers from Stanford University and Palo Alto VA Health Care System in California performed a prospective study to determine the prevalence of Barrett's esophagus in asymptomatic women undergoing routine screening colonoscopy or endoscopic examination before bariatric surgery. Short-segment Barrett's esophagus was detected in six percent of 126 asymptomatic women undergoing these procedures. Patients found to have Barrett's esophagus were more likely to be 61 to 70 years of age, but there was no difference in mean body mass index, ethnicity, or tobacco or alcohol use between patients with and without Barrett's esophagus.
Although Barrett's esophagus was most commonly observed in the 61- to 70-year age cohort in both groups, Barrett's esophagus was only detected in patients younger than the age of 50 in the pre"“bariatric surgery patients. The most likely explanation for this finding would be the increased risk of Barrett's esophagus associated with obesity that has been previously reported. Researchers stated that further studies examining the natural history of asymptomatic Barrett's esophagus would be useful to determine the need for endoscopic screening and surveillance in this patient population.
"EUS-FNA predicts 5-year survival in pancreatic endocrine tumors"
Endoscopic ultrasound consists of a flexible endoscope which has a small ultrasound device built into the end. The ultrasound component produces sound waves that create visual images of the digestive tract which extend beyond the inner surface lining. EUS can be used to evaluate an abnormality below the surface such as a growth that was detected at a prior endoscopy or by X-ray. EUS can also be used to diagnose diseases of the pancreas, bile duct, and gallbladder when other tests are inconclusive, and can be used to determine the stage of cancers. Tissue samples, using a fine needle aspiration technique (FNA), can be obtained in real time with EUS guidance should an abnormality be seen.
Pancreatic endocrine tumors (PETs) are tumors from the abnormal growth of pancreatic cells that produce hormone-like chemicals and differ in clinical behavior and prognosis than the more common type of pancreatic cancer of the pancreas glands (adenocarcinoma). Determination of malignant (cancerous) potential through specimens obtained by EUS-FNA can help in the management of these patients. Researchers at the Institute Paoli-Calmettes, Marseilles, France, set out to determine the value of EUS-FNA for the diagnosis of PETs and for classifying the underlying malignant potential of these tumors based on the proposed World Health Organization (WHO) classification. Although EUS-FNA is often used for diagnosing PET, there are no data on its accuracy in determining the malignant potential of PETs and in applying the WHO classification. This single-center, retrospective cohort study, the largest experience of EUS-FNA in the diagnosis of PET, involved 86 patients who had been diagnosed with PETs and submitted to EUS-FNA from January 1999 to August 2008.
Overall, in 90 percent of patients in this study, PET was diagnosed with EUS-FNA. The sensitivity did not vary with tumor size, type, location, or the presence of hormonal secretion. Of 86 patients, 35 percent were submitted to surgical resection. There was a fair correlation between the WHO classification obtained by EUS-FNA and that obtained by surgery in the 24 patients who had records on both procedures available. All 10 patients classified as having an endocrine carcinoma (cancer) by EUS-FNA had the diagnosis confirmed by surgery. The five-year survival rates were 100 percent for endocrine tumors, 68 percent for well-differentiated endocrine carcinomas, and 30 percent for poorly differentiated endocrine carcinomas.
The researchers concluded that EUS-FNA is a safe and highly accurate technique for diagnosing PET and that it is possible to determine the potential malignant behavior of a PET in specimens obtained byEUS-FNA by applying the WHO classification. EUS-FNA findings predict five-year survival in patients with PET and this may help to better guide the therapeutic approach for these patients.
"EUS in pediatric patients"
Although the role of EUS is well established in adult gastrointestinal (GI) and pacreatobiliary (pancreas, bile ducts, gallbladder) disease, knowledge of EUS in children is limited. This is because of the relatively low incidence of pancreatobiliary and GI neoplasias, presumptive limitations in the size of EUS equipment and accessories, the need for general anesthesia, and the lack of highly trained and experienced endosonographers in pediatric patients. With the refinement of techniques and advances in endosonographic design, several case reports and studies found successful use of EUS in pediatric patients. The aim of this retrospective study was to describe clinical and demographic characteristics, indications, feasibility, safety, and impact of EUS in the pediatric patient population from two university hospitals.
All EUS procedures performed from September 2001 to September 2008 at Oregon Health & Science University, Portland, Oregon, and University of Utah School of Medicine, Salt Lake City, Utah were reviewed. Patients younger than 18 years of age were identified. All EUS procedures were performed by experienced endosonographers who independently performed more than 1,000 EUS procedures in adults. All procedures were performed in facilities specialized in the care of adult patients.
Over the seven-year period, 40 of 6,724 EUS procedures were performed on 38 patients younger than 18 years of age. The procedure was successful in all patients and no complications related to sedation, EUS or EUS-FNA were encountered. The study also found that standard adult EUS equipment and accessories could be used in all patients to successfully perform procedures in children three years of age or older. Disorders of the pancreatobiliary system were the primary indication in the majority of the study cases (62.5 percent), which is in keeping with previous studies.
Researchers concluded that EUS and EUS-FNA are feasible and safe and have a significant impact on the management of pediatric GI, pancreatobiliary, and mediastinal (area of the chest between the lungs) diseases. EUS allows the physician to avoid having to perform more invasive and higher risk procedures such as endoscopic retrograde cholangiopancreatography, laparoscopy, and mediastinoscopy. For the gastroenterologist performing these procedures in adults, knowledge of common congenital abnormalities of the GI and pancreaticobiliary tracts is important. The gastroenterologist endosonographer treating adults should also have close communication with colleagues in pediatric GI and surgery. Although standard-size instruments may be used even in younger children, the need for deeper levels of sedation and maintenance of a patent airway will frequently require the assistance of anesthesia services.
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