Abstracts
W1185 Endoscopic Ultrasound (EUS) in the Evaluation of Patients with Suspected Choledocholithiasis but Negative Cross-Sectional Imaging (Transabdominal Ultrasonography or Abdominal CT Scan) Tju-Siang Chua, Kwong-Ming Fock, Eng-Kiong Teo, Jessica Tan, Choo-Hean Poh Aim: To evaluate the usefulness of EUS in the evaluation of patients with a clinical suspicion of choledocholithiasis in whom cross-sectional imaging with either transabdominal ultrasound (US) or abdominal CT does not detect any common bile duct (CBD) stones. Method: This was a prospective study conducted on patients presenting with symptoms referable to the biliary system (biliary colic, cholangitis, jaundice) who had a transabdominal ultrasound or abdominal CT scan that was negative for stones or sludge in the CBD. These patients subsequently underwent EUS examination which was performed using a radial scanning echoendoscope (Olympus GF-UM160). Patients in whom choledocholithiasis or sludge in the CBD was noted underwent therapeutic ERCP and were offered laparoscopic cholecystectomy. Those in whom EUS did not provide a positive diagnosis were followed up clinically. Results: 50 patients (26M/24F) were included in the study. Of these, 14 had a dilated CBD noted on transabdominal US but the cause of the dilatation could not be determined. The remaining 36 patients had a non-dilated CBD on transabdominal US. In 30 out of the 50 patients (60%), choledocholithiasis was diagnosed by EUS. Another 8 patients (16%) had sludge noted in the CBD by EUS. The EUS diagnosis of choledocholithiasis or sludge in the common bile duct was verified in all 38 patients by therapeutic ERCP with resolution of symptoms soon after stone extraction or biliary stent insertion. Of the remaining patients, 10 were diagnosed with cholelithiasis but no lesion could be identified in the common bile duct. In all 10 patients, clinical signs and liver biochemical abnormalities resolved soon after hospital admission, suggestive of passage of a stone through the CBD. These patients were offered cholecytectomy. 2 patients did not have a positive EUS diagnosis. Both of these patients presented with a mixed picture on liver function tests and declined liver biopsy. At 3-month follow-up, their symptoms and/or signs had resolved. Conclusions: EUS is a useful imaging method for the evaluation of patients with suspected choledocholithiasis but in whom cross-sectional abdominal imaging (US or CT) is negative for CBD stones. When EUS is negative for choledocholithiasis or microlithiasis, ERCP along its accompanying risks can be avoided.
W1186 Geographic and Patient-Level Variations in Utilization of Endoscopic Ultrasonography in Patients with Esophageal Cancer Ananya Das, Amitabh Chak, Jonathan Payes, Michael V. Sivak, Gregory S. Cooper EUS is widely used in the evaluation and staging of patients with esophageal cancers. No information currently exists regarding geographic and patient-level variations in the utilization of EUS procedures in this population. Objective: To study the age, gender, race, tumor histology, stage and locale of residence related factors that are associated with EUS evaluation in these patients. Methods: We identified all persons aged 66 years or older who were diagnosed with esophageal cancer between January 1994, and December 1999, and resided in a SEER area. Relevant demographic, cancer specific information and EUS procedural information was obtained from the linked SEER-Medicare database. The association of categorical variables with performance of EUS within 90 days of diagnosis was assessed by the chi-square test. A logistic regression model was developed with performance of EUS as the dependent variable to study the independent association of these demographic and clinical variables. Results: There were 3,786 patients with esophageal cancer (47% squamous cell cancer) diagnosed during the study period. Only 341 (9%) patients had a EUS examination for tumor evaluation and staging. Evaluation with EUS was significantly more common in white patients (10.5% vs.7.3%, p ! 0.02), men (10.8% vs. 8.0%, p ! 0.02), patients younger than 75 years (12.6% vs. 7.0%, p ! 0.001) patients with non-squamous cell carcinoma (14% vs. 7.2%, p ! 0.001) and in those with loco-regional tumor stage (15.4% vs. 4.1% for distant stage). There was marked variation in the rates of utilization of EUS in different SEER locations with rates ranging from 4.9% to 13.5%. In multivariate analysis, age, tumor histology and stage and also, SEER location were significant
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predictors of utilization of EUS. Conclusion: As with other endoscopic and surgical procedures, there is significant geographic and some patient-level variations in the utilization of EUS for esophageal cancer staging. Given that EUS is a technically sophisticated investigation, requires expensive instruments and there is a shortage of trained personnel these differences are also likely to be true with respect to other gastrointestinal cancers.
W1187 Temporal Trend in Utilization of EUS in Patients with Esophageal Cancer Ananya Das, Jonathan Payes, Amitabh Chak, Michael V. Sivak, Gregory S. Cooper Endoscopic ultrasonography (EUS) staging is considered an important technological advance in the evaluation of esophageal cancers. However, available information suggests that only a minority of patients with esophageal cancer eligible for EUS actually undergo the procedure. Given what is known about dissemination of new technology, potential temporal increases in the utilization of EUS is worthy of investigation. Objective: To study trends in utilization of EUS in a population-based cohort of Medicare beneficiaries with esophageal cancer. Methods: The cohort for this study was assembled from the linked SEER-Medicare database, developed jointly by the National Cancer Institute and the Center for Medicare and Medicaid Services. All persons aged 66 years or older, who were diagnosed with esophageal cancer, resided in a SEER area, and were captured in both the SEER cancer registry and the Medicare claims database between January 1994, (when procedural codes for EUS became generally available) and December 1999 were identified. Relevant demographic, cancer specific information and EUS procedural information was extracted from the SEER registry files and the Medicare claims files. A logistic regression model was developed with performance of EUS as the dependent variable to study the independent effect of year of diagnosis after controlling for other relevant demographic and clinical variables. Results: There were 3,786 patients with esophageal cancer (47% squamous cell cancer) diagnosed during the study period. Only 341 (9%) patients had a EUS examination for tumor evaluation and staging. While the number of Medicare patients with newly diagnosed esophageal cancer has remained relatively stable, the rates of EUS utilization in these patients have steadily increased from 4.1% in 1994 to 14.2% in 1999 (Figure). After adjustment for age at diagnosis, race, gender, co-morbidity score, histology, and tumor stage, year of diagnosis between 1994 to 1996 was an independent predictor of lack of EUS evaluation (odds ratio 0.4 (95% CI, 0.310.51)). Conclusion: Although EUS evaluation is consistently performed in a minority of patients with esophageal cancer, there is an increasing trend in the utilization of EUS procedures in these patients. The findings presumably reflect increasing availability with the dissemination of EUS technology from select academic centers to the community.
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