A decision analysis model of patients with suspected pancreatic cancer was constructed. The authors analyzed costs, failure rate, testing characteristics, and complication rates of four commonly employed diagnostic modalities: 1) computerized tomography or ultrasound-guided fine-needle aspiration (CT/US-FNA), 2) endoscopic retrograde cholangiopancreatography with brushings (ERCP-B), 3) Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA), and 4) laparoscopic surgical biopsy. If the first attempt with a particular modality failed, a different modality was employed to identify the most preferable secondary biopsy strategy. This analysis identified EUS-FNA as the preferred initial modality for the diagnosis of pancreatic cancer. Expected costs and strategies in decreasing optimality included: 1) EUS-FNA (1,405 dollars), 2) ERCP-B (1,432 dollars), 3) CT/US-FNA (3,682 dollars), and 4) surgery (17,711 dollars).

Various modalities currently exist for tissue confirmation of suspected pancreatic cancer prior to therapy. This cost-minimization study illustrates that EUS-FNA is the best initial and the preferred secondary alternative method for the diagnosis of suspected pancreatic cancer. The authors suggest that in addition to local expertise and availability, costs and diagnostic yield should be considered when choosing an optimal diagnostic strategy. This is a well done paper that supports using EUS-FNA as the preferred method for tissue diagnosis of pancreatic cancer. However, the actual modality chosen may depend on local expertise since EUS expertise is not uniformly available. Regardless of the method used for tissue diagnosis of a pancreatic mass, one should consider the clinical impact of obtaining a tissue diagnosis as every pancreatic mass may not need a preoperative tissue confirmation.

The Olympus EU-IP2 three-dimensional endoscopic ultrasound (3D-EUS) imaging system makes it possible to display tumors in three dimensions and estimate their volume. Experimental and clinical studies of the volume estimation function of the Olympus EU-IP2 system was carried out by the authors to evaluate its accuracy and assess the extent of tumor shrinkage caused by fixation, dehydration, and staining. In the clinical studies, compared with the histologically determined tumor volume (100%), the mean estimated tumor volume was 178 +/- 48.2% in situ, 168 +/- 31.3% in resected specimens, and 137 +/- 31.5% after fixation. The authors concluded that the volume of gastrointestinal lesions can be estimated by 3D-EUS, although it is overestimated in comparison with actual values. 3D-EUS also allows direct comparisons to be made between the tumor volume before surgery and the volume of fixed pathological specimens, so that the rate of tumor shrinkage can be estimated.

The spatial resolution of 3-D images is better than 2-D EUS images. Although experience with 3-D EUS is relatively early, it is worthwhile to discuss some potential clinical applications of 3-D EUS. A number of studies have shown that apart from revealing relationship of a tumor to surrounding structures in three dimensions, 3-D EUS also is able to estimate tumor volume. As laparoscopic and other minimally invasive surgery becomes more and more common, these 3-D images during EUS may become even more valuable to the surgeon prior to embarking upon a minimally invasive surgical procedure. There may be value in knowing the tumor volume to decide the dose of radiation or chemo therapy. Some early data suggest that intervention and needle biopsy are possible under 3-D EUS guidance, and it may allow precise control of the biopsy needle within the target lesion. This may further improve the safety and accuracy of EUS guided fine needle aspiration. However, currently 3-D EUS is still in the research arena and not ready for routine clinical application.

This study assessed knowledge of the indications and the utility of EUS among gastroenterologists and non-gastroenterologists in a large multispecialty academic practice. The authors designed a questionnaire that tested knowledge of the indications for EUS with respect to 4 organ systems: esophagus, gastroduodenum, hepatopancreatobiliary system, and colorectum. The questionnaire was distributed by electronic mail to gastroenterologists, general internists, non-gastroenterologist subspecialists, and surgeons in a large multispecialty practice. Knowledge of appropriate indications was highest among gastroenterologists (84.3%) compared with internists (68.9%), non-gastroenterologist specialists (65.4%), and surgeons (65.3%) (p < 0.0001). Among all non-gastroenterologists, knowledge of indications for hepatopancreatobiliary (mean 66.3% correct responses) and colorectal applications (64.0%) was inferior to knowledge of esophageal (71.5%) and gastroduodenal (83.5%) applications. The authors concluded that internists, non-gastroenterologist specialists, and surgeons in a large multispeciality practice have moderate knowledge of the indications and the utility of EUS. Knowledge was at the lowest level for hepatopancreatobiliary and colorectal applications of EUS for all 3 groups of non-gastroenterologists.

The authors of the above study have rightly stated, "Future studies should focus on the education of non-gastroenterologists regarding the role of EUS and assess the impact of such education on the appropriateness of EUS referral patterns.” EUS is a relatively new “kid on the block” in GI and has now come out of the research arena as a routinely needed, clinically useful modality. The results of the above study are partly due to most of the earlier EUS literature being only published in GI journals. Since the indications and impact of EUS directly involve numerous other disciplines, it has now become important to increase awareness and educate non-GI physicians about EUS so that its full potential can be realized, and it is performed for appropriate indications.