Shyam Varadarajulu, MDa∗ and Robert H. Hawes, MDb,     aCenter for Interventional Endoscopy, Florida Hospital, 601 East Rollins Street, Orlando, FL 32803, USA; bInstitute for Minimally Invasive Therapy, Florida Hospital, 601 East Rollins Street, Orlando, FL 32803, USA

∗Corresponding author. Mail: svaradarajulu@yahoo.com

The diagnostic performance of endoscopic ultrasound–guided fine-needle aspiration is strongly dependent on the availability of an onsite cytopathologist. The diagnosis of some rare tumors may require ancillary testing for which a histologic core biopsy is required. There is increasing interest in evaluating core tissue for molecular markers that may serve as prognostic predictors and targets for focused chemotherapy in patients with cancer. If core tissue can be procured efficiently and reliably at endoscopic ultrasound, this will eliminate the need for an onsite cytopathologist, accurately diagnose tumors that are occasionally missed by fine-needle aspiration cytology, and enable the assessment for molecular markers.

Keywords

Endoscopic ultrasound

Fine-needle aspiration

Fine-needle biopsy

Core biopsy

Tissue acquisition

Key points

The impact of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) on the practice of pancreatic pathology is considered a disruptive innovation.1 EUS-FNA rightly fits the description of a disruptive technology: “technically straight forward, consisting of off-the-shelf components put together in a way that is often simpler than prior approaches.”2 EUS-FNA consists of three technologies, each of which is disruptive in its own way: fiberoptic endoscopy was disruptive to rigid endoscopy, ultrasound to radiograph, and cytology to histology.1 A recent study analyzed the pattern of pancreatic pathology examinations during a 20-year period in a tertiary referral center with relationship to implementation of a EUS-FNA program.1 The sensitivity and specificity for cancer diagnosis improved from 55% and 78% to 88% and 96%, respectively, after implementation of the EUS-FNA program. Unsatisfactory (7% vs 1%), atypical (16% vs 4%), and suspicious (16% vs 3%) diagnosis were significantly reduced. After implementation of the EUS-FNA program, whereas the average percentage of annual cases managed by cytology alone increased from 19% to 51%, the percentage managed by histology alone declined from 56% to 23%. Consequently, non–EUS-guided FNA cytology decreased from 36% to 1% and needle biopsies from 29% to 9%. Because EUS-FNA brought about a much-needed improvement in diagnostic accuracy, it resulted in the displacement of histologic diagnosis in management of pancreatic diseases. This is evident from a recent study conducted by these authors that examined the 5-year trend (2006–2010) in tissue acquisition in pancreatic diseases in the United States using the Medicare database: The use of EUS-FNA increased by 69.3%, surgical biopsy declined by 41.7%, and the use of percutaneous biopsy has remained stable.3

Although EUS-FNA can be regarded as a disruptive innovation, it is important for endosonographers to recognize the imperfections of EUS and make constant refinements and incremental improvements to existing techniques, technologies, and practice patterns. This self-evaluation is important because it enables one to see “what is next.” This might occasionally result in technological development that is offered in excess of what the consumer (endosonographers) demands or needs. Herein, the consumer weighs-in to differentiate between a sustaining “valued-based” technology and just “another” technology. Although biased investigators and industry-driven studies may make this distinction difficult, fortunately in medicine only those technologies that impact patient care in a meaningful manner eventually withstand the test of time.

Limitations of EUS-guided FNA cytology

There are three limitations to EUS-guided FNA that if overcome can propel the technology even further: (1) the availability of onsite cytopathology support, (2) the occasional dependence on histology to establish a diagnosis that is otherwise not possible with FNA cytology, and (3) the ability to reliably assess the tissue sample for molecular markers so that patients can be risk stratified and treated with tailored chemotherapeutic agents.