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Biomedical subjects

I Waxman

Publications and source records attributed to I Waxman.

At least 19 recordsLinked to original sources
PubMed2001

Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population.

BACKGROUND & AIMS: To assess the prevalence of flat and depressed (F&D) colorectal adenomas in the United States, we performed a prospective study of 211 American patients. METHODS: Dye-assisted colonoscopy was performed in the presence of both an American and a Japanese investigator. RESULTS: F&D lesions were found in 22.7% of patients, and these were more likely to be adenomatous than polypoid lesions (82% vs. 67%; P = 0.03) and contained more invasive cancer (4.5% vs. 0%; P = 0.04), which also appeared to be at a disproportionately advanced stage. The average size of all F&D advanced lesions (high-grade dysplasia and cancer) was significantly smaller than comparable polypoid lesions (10.75 +/- 2.7 mm vs. 20 +/- 2.9 mm; P < 0.05). F&D adenomas showed significantly stronger fragile histidine triad (FHIT) expression and lower p53 reactivity than similarly sized polypoid adenomas, whereas proliferative and apoptotic indices were similar in both groups. CONCLUSIONS: We conclude that there is a significant prevalence of colonic F&D colorectal adenomas in this country and that these lesions have significantly different biologic features than polypoid lesions. The clinical and epidemiologic implications of these findings for American patients need to be addressed in further studies.

Acid Anhydride Hydrolases↗
PubMed2000

Clinical outcome of endoscopic mucosal resection for superficial GI lesions and the role of high-frequency US probe sonography in an American population.

BACKGROUND: Endoscopic mucosal resection, a major advance in endoscopy, provides an endoscopic option for management of focal and superficial lesions of the gastrointestinal tract. Although popular in the Orient due to the high incidence of superficial neoplasia, there are scant data on its use in the United States. Our aim was to assess the efficacy and safety of endoscopic mucosal resection in our patient population and evaluate whether high-frequency ultrasound (US) probe sonography provides useful information relative to the procedure. METHODS: Endoscopic mucosal resection was performed in 32 of 33 patients referred for endoscopic management of superficial neoplastic or submucosal lesions. High-frequency US probe sonography was performed with a 20 MHz US probe. Endoscopic mucosal resection was performed after submucosal saline solution injection with the strip biopsy technique. RESULTS: Thirty-two superficial lesions were resected. Of 24 epithelial lesions resected, 22 were intramucosal and 2 had early submucosal invasion (SM1); the 2 patients with the latter 2 lesions were poor candidates for surgery. Depth of penetration of 25 of 26 lesions scanned was accurately predicted by high-frequency US probe sonography. Eight lesions raised from the submucosa. Minor complications were limited to the colon. Of the 7 patients with carcinomas, 6 had no evidence of recurrence at a mean follow-up of 12 months; 1 died of a second primary cancer. CONCLUSIONS: Endoscopic mucosal resection provided definitive therapy for 24 early-stage neoplastic lesions and provided a diagnosis in the remaining 8. In our study, the technique proved to be safe with only three minor complications noted. High-frequency US probe sonography accurately delineated the depth of penetration of all lesions scanned, therefore making it an ideal imaging modality for selecting patients who may benefit from endoscopic mucosal resection.

Biopsy↗
PubMed2000

A multispecialty approach to the diagnosis and management of pancreatic cancer.

This article reviews recent developments in pancreatic cancer research and offers a multispecialty perspective on the diagnosis and management of this challenging disease. Current findings in the molecular biology of the disease and their implications for management are examined, as well as development in diagnostic techniques, including helical computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangio-pancreatography (MRCP), and, particularly, endoscopic ultrasound-guided fine-needle aspiration. Surgical management, the role of adjuvant/neoadjuvant chemoradiation therapy, and the critical importance of accurate preoperative imaging are also addressed in this review. Palliative techniques, including endoscopic stenting for malignant obstructive jaundice and chemotherapy for locally advanced and metastatic disease, are discussed, and results of recent clinical trials in pancreatic cancer are summarized. Finally, future directions for research are identified.

Humans↗
PubMed1999

Microcystic adenoma of the pancreas: cytologic appearance on percutaneous and endoscopic ultrasound-guided fine-needle aspiration: report of a case.

Microcystic adenoma is an uncommon neoplasm of the pancreas usually affecting older people. Its histologic features have been well characterized. The cytologic appearance of this tumor has been described only rarely, however, Microcystic adenomas may enlarge considerably and often produce symptoms related to their compression to adjacent anatomic structures. The fact that this neoplasm is almost always benign indicates the need for accurate preoperative diagnosis to differentiate it from other, more common, malignant or potentially malignant tumors of the pancreas. We present a case of pancreatic microcystic adenoma initially diagnosed by percutaneous image-guided fine-needle aspiration cytologic examination and core biopsy and further evaluated by endoscopic ultrasound-guided fine-needle aspiration on follow-up. This case report illustrates that microcystic adenoma of the pancreas can be accurately diagnosed by aspiration cytology. Fine-needle aspiration--percutaneous, guided by computerized tomography, or endoscopically guided by ultrasonography--constitutes a reliable and cost-efficient diagnostic tool associated with minimal trauma to the patient.

Adenoma↗
PubMed1997

Use of the 25 mm flanged esophageal Z stent for malignant dysphagia: a prospective multicenter trial.

BACKGROUND: An initial multicenter study using a 21 mm flanged esophageal Z stent demonstrated excellent palliation but an 11% immediate complication rate at placement and a 27% migration rate at 1 month. This North American multicenter trial prospectively studied a 25 mm flanged Z stent to define its palliative ability and whether the increased diameter affected placement or migration problems. METHODS: Fifty patients who had esophageal Z stents at seven university or regional referral hospitals were prospectively studied. Indications for prosthesis placement, previous therapy, patient demographics, incidence of concomitant tracheoesophageal fistula, and degree of dysphagia were defined, as were procedural and subsequent stent-related problems, survival times, the ability to occlude a tracheoesophageal fistula, and subsequent degree of dysphagia. RESULTS: Twenty-four patients had infiltrating malignancy (16 exophytic and 10 extrinsic), 9 of whom had concomitant tracheoesophageal fistulas. Ten patients (20%) had misplaced stents requiring retrieval and replacement, 12 patients (24%) had subsequent stent-related problems including exsanguination (2), aspiration (3), tumor overgrowth (3), and postplacement migration (4) (8%). There was statistically significant improvement in prestent versus poststent dysphagia and two thirds of patients had complete occlusion of their tracheoesophageal fistula. CONCLUSIONS: Redesign of the esophageal Z stent has decreased the migration rate without increasing placement or subsequent erosion problems. Its efficacy appears comparable to the currently marketed Z stent for the palliation of malignant dysphagia and occlusion of tracheoesophageal fistula.

Aged↗
PubMed1997

Endosonography in columnar-lined esophagus.

As suggested from these results, the routine use of EUS in its present form to screen patients with Barrett's esophagus is neither justified nor cost-effective. The use of high-resolution ultrasound probe sonography employing high-frequency probes (20 MHz) to improve detection of intramucosal adenocarcinoma in Barrett's esophagus or in staging early carcinoma (Figs. 1 and 2) is currently under investigation, and its role remains to be determined.

Adenocarcinoma↗
PubMed1997

Pancreatic duct stricture length at ERCP predicts tumor size and pathological stage of pancreatic cancer.

OBJECTIVE: To determine whether findings on endoscopic retrograde cholangiopancreatography (ERCP) could provide useful prognostic information in resectable pancreatic cancer. METHODS: We retrospectively identified 18 patients with resectable pancreatic cancer (defined as no evidence of metastatic disease or vascular involvement on CT scan) who had undergone ERCP prior to an attempt at curative resection between 1991 and 1996. Common bile duct and pancreatic duct stricture lengths were measured on ERCP and compared with the size of the resected tumor. Magnification was controlled for by comparison with endoscope diameter. Stricture length was plotted against actual tumor size, and a correlation analysis was performed. RESULTS: Pancreatic duct stricture length measured on ERCP correlated with both size (p < 0.001) and stage (p < 0.002) in resectable pancreatic cancer. CONCLUSIONS: ERCP may provide useful preoperative prognostic as well as diagnostic information in pancreatic cancer.

Adult↗
PubMed1996

Prospective multicenter trial of esophageal Z-stent placement for malignant dysphagia and tracheoesophageal fistula.

BACKGROUND: Conventional esophageal prosthesis placement has been associated with a 6% to 8% perforation rate and numerous postplacement complications. Expandable esophageal stents have been developed to preclude the above but there are few studies that have prospectively defined clinical results and subsequent stent-related complications. METHODS: All patients who underwent esophageal Z-stent placement at nine university or referral hospitals were prospectively assessed. Data collected included patient demographics, acute and subacute placement problems, the ability to occlude airway fistulas, prestent and poststent dysphagia scores, and patient survival. RESULTS: Fifty-four of 56 patients (96%) with refractory dysphagia or malignant esophagoairway fistulae had 73 Z-stents successfully inserted. Initial distal deployment occurred in 13% of the patients and an additional 17% required balloon dilation to achieve maximal diameter. Acute placement complications occurred in 11% of patients and included severe pain (3), bleeding from necrotic tumor (2), and hiatal hernia intussusception (1). No perforations occurred. Eight of 11 patients (73%) had complete tracheoesophageal fistula occlusion and mean dysphagia score (+/- SD) improved from 2.6 (0.7) to 1.1 (1.2) (p < 0.01). Fifteen stents (27%) had delayed migration at a mean of 1 month and 3 required surgery for retrieval. Three patients had ultimate stent erosion resulting in bleeding in 2 (exsanguination 1) or fistula (treated with a conventional stent). CONCLUSIONS: The authors conclude that esophageal Z-stents can be placed safely and successfully in the majority of patients. The tendency of distal deployment during placement and subsequent migration problems at a time distant from placement in a patient subset deserve attention and are currently being addressed.

Adult↗
PubMed1996

Wallstents for metastatic biliary obstruction.

BACKGROUND AND STUDY AIMS: In patients with obstruction of the common bile duct caused by primary pancreaticoblliary tumors, Wallstents have been shown to remain patent for a median duration of 273 days (range: 14-363). However, in one study that included both patients with primary pancreaticobillary malignancies and patients with metastatic malignant disease, the reported median Wallstent patency was found to be significantly shorter. We have studied the patency of Wall-stents in patients with metastatic billary obstruction. PATIENTS AND METHODS: All patients who had received a Wallstent for metastatic biliary obstruction between January 1990 and August 1994 were analyzed retrospectively. Follow-up was achieved by contacting referring physicians and general practitioners, and lasted up to the end of the study period (November 1994) or death of the patient. Follow-up was discontinued if a polyethylene stent was inserted through the Wallstent for treatment of stent dysfunction. RESULTS: 28 patients were identified, including 14 men and 14 women, with a mean age of 61.3 years (range 24-87). Long-term follow-up was possible in 27 patients (96%), for a median duration of 140 days (range 29- 561). Eleven patients died during the study period, and there were three deaths related to Wallstent dysfunction. The median duration of Wallstent patency was 265 days (range 11-519). Wallstent obstruction occurred in 13 patients; seven patients presented with cholangitis, six patients had jaundice. The cause of obstruction was established at endoscopic retrograde cholangiopancreatography in ten patients: seven had tumor ingrowth, and three had tumor overgrowth. Treatment consisted of insertion of a polyethylene stent in seven and placement of a second Wallstent in three patients. CONCLUSION: In patients with metastatic obstruction of the common bile duct, the duration of patency of Wallstents is comparable to that reported in series of Wallstents for primary pancreaticobiliary malignancies.

Adult↗