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Roy K H Wong

Publications and source records attributed to Roy K H Wong.

15 recordsLinked to original sources
PubMed2007

Normalization of intestinal metaplasia in the esophagus and esophagogastric junction: incidence and clinical data.

BACKGROUND: Attention has focused on whether normalization, regression, and development of dysplasia and cancer in specialized intestinal metaplasia (SIM) differ among long-segment Barrett's esophagus (LSBE), short-segment BE (SSBE), and esophagogastric junction SIM (EGJSIM). We prospectively followed a cohort of SIM patients receiving long-term antisecretory medications to determine: (a) histologic normalization (no evidence of SIM on biopsy), (b) change in SIM length, (c) incidence of dysplasia and cancer, and (d) factors associated with normalization. METHODS: One hundred forty-eight patients with SIM were identified in our original cohort. Of these, 60.5% (23/38) LSBE, 69.8% (44/63) SSBE, and 72.3% (34/47) EGJSIM patients underwent repeat surveillance over a mean 44.4 +/- 9.7 months. Demographic, clinical, and endoscopic data were obtained. RESULTS: (a) With long-term, antisecretory therapy, normalization occurred in 0/23 LSBE, 30% (13/44) of SSBE, and 68% (23/34) of EGJSIM (P < 0.001). (b) Normalization was more likely with EGJSIM (odds ratio [OR] 6.7, CI 2.3-19.3, P= 0.005), female gender (OR 7.3, CI 2.3-23.1, P= 0.001), or absence of hiatal hernia (OR 2.9, CI 1.02-8.06, P= 0.002). (c) A significant decrease in mean SIM length was noted for the entire population (2.5 +/- 0.3 to 2.13 +/- 0.3 cm, P= 0.004). (d) Follow-up incidence of dysplasia and cancer was 26.1% (3 indefinite, 2 low-grade dysplasia [LGD], 1 cancer) for LSBE, 6.8% (2 indefinite, 1 LGD) for SSBE, and none for EGJSIM (P < 0.004). CONCLUSIONS: (a) Normalization of SIM occurs most frequently in EGJSIM>SSBE>LSBE. (b) Factors associated with normalization favor less severe GER and shorter segments of SIM. (c) Surveillance of LSBE results in the greatest yield for identifying dysplasia and cancer.

Aged↗
PubMed2006

The cost-effectiveness of CT colonography in screening for colorectal neoplasia.

BACKGROUND: We examined the cost-effectiveness of 2- and 3-dimensional computerized tomography (CT) colonography as a screening test for colorectal neoplasia. METHODS: We created a Markov model of the natural history of colorectal cancer. Effectiveness of screening was based upon the diagnostic accuracy of tests in detecting polyps and cancer. RESULTS: CT colonography every 5 or 10 yr was effective and cost-effective relative to no screening. Optical colonoscopy dominates 2-dimensional CT colonography done every 5 or 10 yr. Optical colonoscopy is weakly dominant over 3-dimensional CT colonography done every 10 yr. 3-D CT colonography done every 5 yr is more effective than optical colonoscopy every 10 yr, but costs an incremental 156,000 dollars per life-year gained. Sensitivity analyses show that test costs, accuracy, and adherence are critical determinants of incremental cost-effectiveness. 3-D CT colonography every 5 yr is a dominant strategy if optical colonoscopy costs 1.6 times more than CT colonography. However, optical colonoscopy is a dominant strategy if the sensitivity of CT colonography for 1 cm adenomas is 83% or lower. CONCLUSIONS: CT colonography is an effective screening test for colorectal neoplasia. However, it is more expensive and generally less effective than optical colonoscopy. CT colonography can be reasonably cost-effective when the diagnostic accuracy of CT colonography is high, as with primary 3-dimensional technology, and if costs are about 60% of those of optical colonoscopy. Overall, CT colonography technology will need to improve its accuracy and reliability to be a cost-effective screening option.

Aged↗
PubMed2006

Esophageal foreign bodies: types and techniques for removal.

Patients with esophageal foreign bodies require prompt diagnosis and therapy. The first tasks are to determine the type of object, time since ingestion, location of the object, and the likelihood of associated complications. Patients who have evidence of complete esophageal occlusion or who have ingested a sharp or pointed object require urgent treatment due to the increased risk of complications. Button batteries are particularly injurious in the esophagus and should be removed immediately. Coins in the esophagus should also be removed; however, a brief period of observation is appropriate for coins in the distal esophagus, as some will pass spontaneously. Flexible endoscopy is the therapeutic modality of choice for most patients. The key principles for endoscopic management of esophageal foreign bodies are to protect the airway, to maintain control of the object during extraction, and to avoid causing additional damage. Endotracheal intubation is sometimes necessary, especially in younger children and those at higher risk for aspiration. The use of devices such as an esophageal overtube and a latex protector hood may facilitate safer extraction of sharp/pointed objects. Patients with food impactions usually require treatment of an associated structural lesion of the esophagus.

Journal Article↗
PubMed2006

Achalasia: should we or should we not follow the bag?

This article concerns the long-term therapeutic effect of pneumatic dilations (PDs) in achalasia. Specifically, it is a retrospective study that follows a large cohort of achalasia patients treated with PD. Efficacy and need for repeat PDs were determined utilizing a score obtained from measuring symptoms after PD. After PDs that resulted in symptomatic improvement, patients were followed at 6-month intervals to determine the need for repeat PD. The major point of this article is that exacerbations of symptoms may occur in 35% of patients undergoing PD; however, follow-up at specific intervals using a symptom score to determine the need for repeat PD resulted in excellent long-term success. This article emphasizes the need for continued follow-up of achalasia patients following initial successful therapy.

Catheterization↗
PubMed2005

Use of methylene blue for detection of specialized intestinal metaplasia in GERD patients presenting for screening upper endoscopy.

The ability of randomly obtained biopsy specimens to identify intestinal metaplasia in the distal esophagus is low. Use of vital staining has been suggested, as stains are taken up by areas histologically identified as specialized intestinal metaplasia (SIM). This study evaluated the role of methylene blue (MB) staining for identification of SIM in GERD patients undergoing a screening endoscopy. Chromoendoscopy of the distal esophagus using 1% MB was performed on 52 GERD patients presenting for their first endoscopy. Biopsies were obtained from areas that were stained darkly, stained lightly, unstained, or macroscopically abnormal. In patients with no MB staining, four-quadrant biopsy of the distal esophagus was performed. Twenty-seven patients (52%) showed staining with MB, while 25 patients did not. Two hundred sixty-six biopsies were obtained. SIM was detected in 11 (21%) subjects (SIM+) but not in the remaining 41 (SIM-). One hundred sixty-five biopsies were unstained (25 SIM+, 140 SIM-) and 101 were stained (12 SIM+, 89 SIM-). The per-biopsy sensitivity and specificity of MB for detection of SIM were 32.4 and 85%, while the per-patient sensitivity and specificity were 63.3 and 51.2%. MB staining for detection of SIM in GERD patients without a macroscopic appearance suggestive of a columnar-lined esophagus is a poor screening tool for SIM.

Adult↗
PubMed2003

Schatzki's rings do not protect against acid reflux and may decrease esophageal acid clearance.

Schatzki's rings (SR) are a common cause of intermittent solid food dysphagia, but their etiology is unclear. Many believe they are related to acid reflux, hypothesizing that the rings act as a protective barrier against further reflux. The purpose of this study was to determine whether dilation of SR affected the degree of acid reflux. Twenty patients participated in the study. All patients underwent esophageal manometry and 24-hr pH monitoring off all acid inhibitory medications before and two weeks after esophageal dilation. No significant differences were noted in any of the reflux parameters measured before and after dilation. However, there was a trend toward reduction in symptom score in all patients, a decrease in Johnson-DeMeester score, and a decrease in supine reflux time in patients with thick SR after dilation. There was no correlation between ring diameter and the presence or absence of reflux. In conclusion, Schatzki's rings do not prevent esophageal reflux, and they may act to decrease esophageal acid clearance, especially in the supine position, thereby increasing esophageal acid exposure.

Adult↗
PubMed2003

Screening for Barrett's esophagus in colonoscopy patients with and without heartburn.

BACKGROUND & AIMS: The population prevalence of Barrett's esophagus (BE) is uncertain. Our aim was to describe the prevalence of BE in a volunteer population. METHODS: Upper endoscopy (EGD) was performed in 961 persons with no prior history of EGD who were scheduled for colonoscopy. Symptom questionnaires were completed prior to endoscopy. Biopsy specimens were taken from the gastric cardia and any columnar mucosa extending > or =5 mm into the tubular esophagus and from the stomach for H. pylori infection in the last 812 patients. RESULTS: The study sample was biased toward persons undergoing colonoscopy, males, and persons with upper GI symptoms. The prevalence of BE was 65 of 961 (6.8%) patients, including 12 (1.2%) with long-segment BE (LSBE). Among 556 subjects who had never had heartburn, the prevalences of BE and LSBE were 5.6% and 0.36%, respectively. Among 384 subjects with a history of any heartburn, the prevalences of BE and LSBE were 8.3% and 2.6%, respectively. In a univariate analysis, LSBE was more common in those with any heartburn vs. those with no heartburn (P = 0.01), but the sample size was insufficient to allow multivariate analysis of predictors of LSBE. In a multivariate analysis, BE was associated with increasing age (P = 0.02), white race (P = 0.03), and negative H. pylori status (P = 0.04). Overall, BE was not associated with heartburn, although heartburn was more common in persons with LSBE or circumferential short segments. CONCLUSIONS: LSBE is very uncommon in patients who have no history of heartburn. SSBE is relatively common in persons age > or =40 years with no prior endoscopy, irrespective of heartburn history.

Adult↗
PubMed2003

Extraesophageal manifestations of GERD.

The association between gastroesophageal reflux disease (GERD) and extraesophageal disease is often referred to as extraesophageal reflux (EER). This article reviews EER, discussing epidemiology, pathogenesis, diagnosis, and treatment with a focus on the most studied and convincing EER disorders-asthma, cough, and laryngitis. Although EER comprises a heterogeneous group of disorders, some general characterizations can be made, as follows. First, although GERD's association with extraesophageal diseases is well-established, definitive evidence of causation has been more elusive, rendering epidemiological data scarce. Secondly, regarding the pathogenesis of EER, 2 basic models have been proposed: direct injury to extraesophageal tissue by acid and pepsin exposure or injury mediated through an esophageal reflex mechanism. Third, because heartburn and regurgitation are often absent in patients with EER, GERD may not be suspected. Even when GERD is suspected, the diagnosis may be difficult to confirm. Although endoscopy and barium esophagram remain important tools for detecting esophageal complications, they may fail to establish the presence of GERD. Even when GERD is diagnosed by endoscopy or barium esophagram, causation between GERD and extraesophageal symptoms cannot be determined. Esophageal pH is the most sensitive tool for detecting GERD, and it plays an important role in EER. However, even pH testing cannot establish GERD's causative relationship to extraesophageal symptoms. In this regard, effective treatment of GERD resulting in significant improvement or remission of the extraesophageal symptoms provides the best evidence for GERD's pathogenic role. Finally, EER generally requires more prolonged and aggressive antisecretory therapy than typical GERD requires.

Animals↗
PubMed2003

Barrett's esophagus and risk of esophageal adenocarcinoma.

Barrett's esophagus is most often seen in white men with chronic heartburn who are generally older than 50 years of age. The prevalence of Barrett's esophagus is 10% to 15% in patients who are undergoing endosocopy for gastroesophageal reflux disease and 1% to 2% in asymptomatic American adults. Barrett's esophagus represents metaplastic columnar tissue with specialized intestinal metaplasia, and this condition carries an increased risk of esophageal adenocarcinoma. Patients with Barrett's esophagus have a risk of esophageal adenocarcinoma 30 to 60 times that of the general population with an incidence rate of over 100 times that of the general population. Esophageal adenocarcinoma has increased dramatically over the past few decades with specialized intestinal metaplasia being the most important risk factor for the development of dysplasia and cancer. Barrett's esophagus develops in the presence of persistent gastroesophageal reflux, which is an independent risk factor for adenocarcinoma. Other risk factors for adenocarcinoma in patients with Barrett's esophagus include length of Barrett's epithelium, low-grade dysplasia, and high-grade dysplasia. New data concerning the pathophysiology and biology of Barrett's epithelium may provide answers to prevent or treat esophageal cancer. This article briefly reviews Barrett's esophagus and focuses on the risk factors associated with its progression to adenocarcinoma.

Adenocarcinoma↗