Assessment of complications of EUS-guided fine-needle aspiration

Technology Insight: current status of endoscopic ultrasonography

Endoscopic ultrasound (EUS) has become the most accurate imaging modality for locoregional cancer staging of the gastrointestinal tract. Fine-needle aspiration (FNA) has added a new level of accuracy for EUS in nodal staging, with reported numbers in the 90% range for luminal and pancreaticobiliary disease. In addition, new non-gastrointestinal applications are being evaluated, such as the role of EUS-FNA for the staging of non-small-cell lung cancer and exploration of the posterior mediastinum. Furthermore, the same techniques that make safe tissue sampling possible are being explored for their use as interventional applications, such as EUS-guided celiac plexus neurolysis, fine-needle injection, EUS-guided pseudocyst drainage, and EUS-guided cholangiography and pancreatography. This review describes the current clinical status of EUS in gastrointestinal oncology, as well as future and novel indications and therapeutic strategies for this technology.

Endoscopic ultrasound in the diagnosis, staging, and management of gastrointestinal and adjacent malignancies

Endoscopic ultrasound (EUS) is a superior modality for local staging of gastrointestinal cancer. In interventional endosonography linear array echoendoscopes permit real-time EUS-guided puncture of target lesions for cytologic evaluation of such lesions. This article describes the basic principles of EUS, established indications pertaining to gastrointestinal cancer and other malignancies, and emerging indications for this minimally invasive technology.

Endoscopic ultrasonography (EUS) in the staging of malignancy

Since first introduced over 20 years ago, endoscopic ultrasonography (EUS) has become established as an important tool in the staging of gastrointestinal malignancies and potentially resectable non-small cell lung cancer. This review describes the current roles of EUS in staging these tumours, highlighting interventional roles, current problem areas and future developments.

Frequency and significance of acute intracystic hemorrhage during EUS-FNA of cystic lesions of the pancreas

BACKGROUND

Complications from EUS-guided FNA of cystic lesions of the pancreas are infrequent. Although several studies have evaluated infectious complications of EUS-guided FNA in this setting, the frequency and the clinical significance of intracystic hemorrhage have not been determined. This study assessed the frequency of acute intracystic hemorrhage during EUS-guided FNA of pancreatic cystic lesions. The characteristic EUS appearance is described.

METHODS

EUS-guided FNA of pancreatic cyst lesions was performed in 50 patients (July 2000 to June 2003). Patients were followed prospectively for the development of complications.

OBSERVATIONS

Acute intracystic hemorrhage occurred during EUS-guided FNA at the site of aspiration in 3 patients (6%: 95% confidence interval [1.3%, 16.6%]). Endosonographically, the bleeding manifested as a small hyperechoic area at the puncture site that progressed gradually over a few minutes to involve the majority of the cyst cavity. EUS-guided FNA was terminated when bleeding was observed. One patient was asymptomatic, but two patients experienced abdominal pain transiently. All patients were treated with a short course of orally administered antibiotics and were observed as outpatients. Clinical history and laboratory parameters did not predict which patients were at risk for intracystic hemorrhage.

CONCLUSIONS

Acute intracystic hemorrhage is a rare complication of EUS-guided FNA; it has a characteristic EUS appearance. Recognition of this event is important, because it permits termination of the procedure and thereby minimizes the potential for more serious bleeding.

Endoscopic sonographically guided fine-needle aspiration yield in submucosal tumors of the gastrointestinal tract

OBJECTIVE

To study the yield of endoscopic ultrasonographically guided fine-needle aspiration cytologic examination in the diagnosis of submucosal masses.

METHODS

From 1999 to 2003, 10 patients underwent ultrasonographically guided fine-needle aspiration for the cytologic diagnosis of submucosal masses in our institution. The endoscopic ultrasonography records and the cytology database were consulted, and the reports were analyzed, as were slide material and the technical aspects related to these procedures. All procedures were performed under conscious sedation and cardiorespiratory monitoring on an outpatient basis. Ten patients (4 men and 6 women; mean age, 60.8 years) were studied.

RESULTS

Eight lesions were located in the stomach, and 2 were located in the esophagus, with a mean diameter of 3.3 cm. An experienced cytopathologist was present on-site during all procedures for assessment of adequacy and preliminary cytologic examination. Cytologic diagnoses were obtained in 8 cases as follows: 6 gastrointestinal stromal tumors, 1 organizing submucosal hematoma, and 1 low-grade mucosa-associated lymphoid tissue-associated lymphoma. Two cases consisted of scant gastric epithelium only and were considered nondiagnostic. The cytologic diagnoses guided further clinical treatment.

CONCLUSIONS

Ultrasonographically guided fine-needle aspiration with cytopathologic analysis has a high accuracy rate (80%) for diagnosing submucosal lesions. These findings potentially affect clinical decision making.

Evaluation and management of cystic pancreatic tumors: emphasis on the role of EUS FNA

Cystic lesions of the pancreas are increasingly recognized and usually represent pseudocysts or cystic pancreatic tumors (CPTs), but also include congenital cysts, acquired cysts, extrapancreatic cysts, or cystic degeneration of solid tumors. It is important to distinguish CPT lesions given their varied prognosis and therapy. Mucinous varieties of CPTs (mucinous cystic neoplasms and intraductal papillary mucinous tumors) are premalignant or malignant, and surgical resection is generally recommended in good operative candidates. In contrast, nonmucinous CPTs include serous cystadenomas with a very low malignant potential, or pseudocysts, which are always benign. As a result, nonmucinous CPTs are generally resected only when inducing symptoms or complications. Review of the clinical, imaging, laboratory, and pathology information may clarify the specific tumor type. The relatively limited accuracy of any one modality requires that we consider the combined results when making management decisions.

Macrocystic pancreatic cystadenoma: The role of EUS and cyst fluid analysis in distinguishing mucinous and serous lesions

BACKGROUND

Benign pancreatic serous cystadenoma usually is morphologically distinguishable from mucinous cystadenomas, which require resection because of their malignant potential. A macrocystic variant of serous cystadenoma recently has been described, rendering this important distinction more difficult. The aim of this study was to determine the EUS and tumor marker characteristics of mucinous cystadenoma compared with macrocystic serous cystadenomas.

METHODS

Medical records for consecutive patients seen between 1995 and 2002, with a histopathologic diagnosis of mucinous cystadenoma or macrocystic serous cystadenoma after surgery, who had undergone a detailed EUS examination, including EUS-guided FNA, were retrospectively reviewed.

RESULTS

A resection specimen was available for 32 mucinous cystadenomas and 9 macrocystic serous cystadenomas. No significant differences were observed with regard to clinical data (age, gender, presence of symptoms), lesion size, and location within the pancreas. All mucinous cystadenomas had a discernible cyst wall (thickened, 66%; focal parietal nodules, 25%) compared with 56% of macrocystic serous cystadenomas (p<0.0001). A thick echo content also was more frequent in mucinous cystadenoma (56% vs. 11%; p=0.04; statistical significance removed by the Bonferroni correction). Microcysts were only observed in macrocystic serous cystadenomas (44%; p=0.0008). The combination of a cyst wall that is thickened and the absence of microcysts had a sensitivity of 100% and specificity of 78% for the diagnosis of mucinous cystadenoma compared with macrocystic serous cystadenoma. Although intracystic carbohydrate-associated antigen 72-4 and mucins M1 were non-discriminatory, low carcinoembryonic antigen (<5 ng/mL) and carbohydrate-associated antigen 19-9 (<50,000 U/mL) values were found in macrocystic serous lesions (respectively, 100% and 100%; p=0.0002 and p=0.0002).

CONCLUSIONS

Although there is considerable overlap, helpful EUS characteristics that differentiate mucinous cystadenoma from macrocystic serous cystadenoma include a thick cyst wall and microcysts. These features, coupled with analysis of aspirated fluid for tumor markers (especially carcinoembryonic antigen), should help to confirm the diagnosis.

Frequency of bacteremia after linear EUS of the upper GI tract with and without FNA

BACKGROUND

Few data are available concerning the frequency of bacteremia after diagnostic EUS or EUS-guided FNA. This study was undertaken to provide these data and to determine whether present guidelines for prophylactic administration of antibiotics to prevent endocarditis during upper endoscopy are applicable to EUS and EUS-guided FNA.

METHODS

A total of 100 patients who were to undergo diagnostic EUS of the upper-GI tract and 50 who were to have upper-GI EUS-guided FNA were enrolled in this prospective study. Blood cultures were obtained before and within 5 minutes after the conclusion of the procedure. In case of bacterial growth, patients were observed for at least 3 days for signs of infection.

RESULTS

After diagnostic EUS, significant bacteremia was found in two patients with esophageal carcinoma (2%: 95% CI[0%, 4.8%]) and after EUS-guided FNA in two patients (4%: 95% CI[0%, 9.6%]). The difference was not statistically significant. None of these patients developed clinical signs of infection. Risk factors predisposing to bacteremia could not be identified.

CONCLUSION

The frequency of bacteremia after EUS, with and without FNA, is within the range of that for diagnostic upper endoscopy. Therefore, the same recommendations for prophylactic administration of antibiotics to prevent endocarditis may be applied in patients undergoing EUS and EUS-guided FNA. The role of esophageal cancer as a predisposing factor to EUS-associated infection remains uncertain.

EUS-guided trucut needle biopsies in patients with solid pancreatic masses: a prospective study

BACKGROUND

A trucut needle biopsy device that can be used to obtain specimens from the pancreas and other perigastric organs under EUS guidance has been developed and successfully tested in animals. Moreover, EUS-guided trucut needle biopsy has been used safely in humans and appears to provide more accurate results than EUS-guided FNA. This study prospectively assessed the clinical utility of this new device in patients with solid pancreatic masses.

METHODS

Twenty-three consecutive patients with radiologically detected solid pancreatic masses underwent EUS-guided trucut needle biopsy. Pancreatic malignancy detected by EUS-guided trucut needle biopsy was considered a definitive diagnosis. Further diagnostic procedures and clinical course were used to establish or exclude the presence of malignancy in all other patients.

RESULTS

Pancreatic tissue was obtained in 17 of the 23 patients (74%), including all patients in whom the transgastric approach was used. No acute or long-term complication was observed. Histopathologic evaluation revealed pancreatic cancer in 12 patients. CT-guided biopsy specimens were obtained in 4 of the 5 patients with a negative EUS-guided trucut needle biopsy result; two were positive for adenocarcinoma. Overall diagnostic accuracy was 61%. Subgroup analysis of the 16 patients in whom EUS-guided trucut needle biopsy was successful and who were available for follow-up revealed a diagnostic accuracy of 87.5%.

CONCLUSIONS

This prospective study demonstrates that EUS-guided trucut needle biopsy, when performed transgastrically, is safe and accurate in the evaluation of patients with solid pancreatic masses.

Role of endoscopic ultrasound in the diagnosis of patients with solid pancreatic masses

Endoscopic ultrasound (EUS) is the most sensitive imaging procedure for the detection of small solid pancreatic masses and is accurate in determining vascular invasion of the portal venous system. Even compared to the new CT techniques, EUS provides excellent results in preoperative staging of solid pancreatic tumors. Compared to helical CT techniques, EUS is less accurate in detecting tumor involvement of the superior mesenteric artery. EUS staging and EUS-guided FNA can be performed in a single-step procedure, to establish the diagnosis of cancer. There is no known negative impact of tumor cell seeding due to EUS-guided fine needle aspiration (FNA). Without FNA, EUS and additional methods are not able to reliably distinguish between inflammatory and malignant masses.

A prospective randomized comparison of curved array and radial echoendoscopy in patients with esophageal cancer

BACKGROUND

Both curved array and radial scanning echoendoscopy are used for locoregional staging of cancer arising in the esophagus or cardia. The accuracy of TNM staging of these malignancies by curved array and radial EUS was compared in a prospective, randomized study.

METHODS

Patients with cancer of the esophagus or cardia were examined by both curved array and radial echoendoscopy in randomized order by the same endosonographer in an unblinded fashion. The staging results and the examination time for the two echoendoscopies were compared and statistically analyzed, and finally compared with surgical and histopathologic staging.

RESULTS

A total of 104 patients underwent EUS; 36 had surgical resection of the tumor, 26 surgical exploration without resection, and 42 did not undergo surgery. Comparison of the TNM staging results for the two echoendoscopies gave high kappa values (T, 0.77; N, 0.75; M, 0.89), indicating excellent agreement. The accuracy of curved array echoendoscopy and radial echoendoscopy by component of the TNM staging system were, respectively, T, 72% and 73%; N, 70% and 77%; and M, 61% and 57%. Mean procedure time for the curved array and radial examinations was, respectively, 15 and 12 minutes (p<0.01).

CONCLUSION

There was no clinically relevant difference between curved array and radial echoendoscopy in the staging of cancer of the esophagus or cardia. The choice of echoendoscope for TNM staging in patients with these malignancies is, therefore, a question of personal preference.

Endoscopic ultrasound-guided biopsy for the diagnosis of focal lesions of the spleen

OBJECTIVES

Needle biopsy of splenic lesions using computed tomography (CT) or ultrasound (US) is difficult if the size of the lesion is small. It may be dangerous if the lesion is adjacent to the splenic hilum or located peripherally. We used endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) to elucidate the tissue diagnosis of splenic abnormalities.

METHODS

EUS-FNA was performed in 12 patients when US- or CT-guided biopsy was inconclusive (n = 5), was not attempted because of small tumor size (0.9-1.4 cm; N = 4), or was considered dangerous (n = 3). A linear echo-endoscope and 22-gauge needles were used for cytology and bacteriology.

RESULTS

The age of the patients was 19-68 yr (median 32 yr). Seven patients were male and five female. The size of the lesions was 0.8-4.2 cm (median 1.4 cm). Cytology was inadequate in one patient. Bacteriology was positive for Staphylococcus aureus and Serratia in one patient each, and cultures were positive for Mycobacterium tuberculosis in two patients. A positive diagnosis was made in 10 of 12 patients (83%). Final diagnoses were tuberculosis in two patients, Hodgkin's disease in two, sarcoidosis in two, abscesses in two, metastatic colon cancer in one, and infarction in one. Suspected recurrence of non-Hodgkin's lymphoma was not confirmed in one case. One patient experienced pain after puncture, but no hematoma was demonstrated on subsequent US examination.

CONCLUSIONS

EUS-FNA cytodiagnosis in patients with unknown splenic lesions seems feasible, even in very small foci, when CT- or US-guided biopsy fails. Additional material for bacteriology may show benign treatable diseases such as abscesses or tuberculosis.

Interventional endoscopic ultrasound

Endoscopic ultrasound (EUS) has been used in clinical practice for the past two decades, mainly for staging upper gastrointestinal tract tumours. More recently the technique has been used to guide interventional procedures, particularly EUS-guided biopsy. In this review we describe the equipment and technique required for interventional EUS. We also discuss with illustrations the current clinical applications, potential complications and developments for the future.

Gastrointestinal endoscopic ultrasonography

Although conventional endoscopy provides excellent visualization of gastrointestinal mucosa, it provides little information about intramural or nearby extramural lesions. The imaging of intraabdominal structures by conventional transabdominal ultrasound is degraded by ultrasound energy attenuation with distance. The provision of an ultrasound probe on a flexible gastrointestinal endoscope, to form an echoendoscope, provides excellent imaging of the gastrointestinal wall and of adjacent extramural structures. During the last two decades, endoscopic ultrasound, using an echoendoscope, has revolutionized the diagnosis and treatment of gastrointestinal diseases that affect the submucosa, deep bowel wall, and adjacent extramural structures. This article reviews the role of endoscopic ultrasound in the diagnosis and treatment of gastrointestinal disease, including standard and promising new applications, as well as standard and emerging new technology.

Diagnosis and fine needle aspiration of pancreatic pseudocysts: the role of endoscopic ultrasound

Pseudocysts are localized collections of pancreatic fluid surrounded by nonepithelialized granulation tissue that occur following an insult to the pancreas. High image resolution and the ability sample in real-time by fine needle aspiration permit accurate distinction between various cystic lesions in the pancreas by endoscopic ultrasound (EUS). Other cyst characteristics and background pancreatic changes detectable at EUS assist in the diagnostic process. The use of Doppler flow ultrasound allows diagnosis of important pseudocyst complications such as pseudoaneurysms and varices. Endoscopic approaches to the drainage of symptomatic lesions previously relied on the use of cross-sectional imaging studies such as computed tomography scanning in combination with stent placement using a duodenoscope in the presence of an endoscopically visible cyst bulge. EUS facilitates this process allowing accurate imaging of the lesion prior to stent placement via the echoendoscope and overcomes many of the drawbacks and pitfalls of other endoscopic techniques.

Role of tumor markers in the diagnosis of cystic and intraductal neoplasms

Despite recent advances in imaging procedures, the correct diagnosis of cystic lesions of the pancreas is lacking in about one third of cases. Cyst fluid analysis can help in the differential diagnosis, particularly in patients with unilocular or paucilocular lesions, thus precluding unjustified resection in patients with benign cystic lesions of the pancreas. Although use of cystic fluid marker analysis is helpful in several situations, it is crucial to carefully evaluate the clinical context with appraisal of patient's demographics, clinical symptoms, and morphologic data. A multidisciplinary approach is advised and should improve the overall diagnostic performance and lead to better management strategies in patients presenting with such tumors of the pancreas.

Endoscopic ultrasound of the pancreas: tissue acquisition and intervention

Endoscopic ultrasound is an established modality for staging gastrointestinal and pancreatic malignancies. Since the development of the linear array echoendoscope, the field of interventional endoscopy has continued to evolve as an adjunctive method to standard endosonography. The ability to sample extraluminal lesions or lymph nodes has overcome the initial limitations of endoscopic ultrasound and provided a list of attractive endoscopic ultrasound-guided therapeutic applications.This review focuses on recent advancements in the field of interventional endosonography related to the diagnosis and therapy of pancreatic diseases. In particular, the article reviews the role of endoscopic ultrasound-guided fine-needle aspiration in diagnosing various pancreatic diseases; the role of endoscopic ultrasound-guided fine-needle injection in delivering neurolytic, chemotherapeutic, or biologic agents; and emerging procedures like endoscopic ultrasound-assisted biliary bypass in the setting of malignant biliary obstruction.

Endoscopic ultrasound

Indications and the clinical utility of endosonography have evolved as new technology, such as linear array echoendoscopes and EUS-guided fine needle aspiration, has emerged. The most noteworthy of the EUS applications are for cancer staging; including rectal, pancreatic, lung, and esophageal malignancies. There is little doubt that EUS is a powerful tool for cancer imaging, but its clinical impact in patient care and management has yet to be validated in prospective outcome studies. Other imaging modalities such as positron emission tomography (PET), dual-phased helical CT, and MR imaging technology will undoubtedly provide increasingly accurate diagnostic and staging information for gastrointestinal diseases. EUS imaging alone may assume a less significant role in relation to these noninvasive modalities in the future. EUS-guided FNA, as well as therapeutic EUS applications, will likely continue to expand in scope and play an important role in clinical medicine for many years to come.

Interventional endoscopy in the diagnosis and staging of upper gastrointestinal malignancy

Increased population longevity as well as an emphasis on earlier diagnosis and more effective treatment of cancer have created an environment for new technologies and techniques to flourish. Some of the endoscopic entities discussed in this article have not been fully validated in clinical practice. Innovative spectroscopic modalities hold a great deal of promise, but are years away from general applicability. In contrast, many interventional endoscopic techniques are currently available and confer heightened levels of diagnostic and staging accuracy for gastric and esophageal malignancies. Earlier diagnosis can identify patients who may be eligible for less-invasive treatment options such as EMR. Minimally invasive treatment options and maximum staging accuracy are more important for patients who are marginal surgical candidates and for accurate comparison of clinical trials studying treatment options. Our challenge for the future is to properly integrate these technologic advances with the science of good medical practice.

Interventional endoscopy, neoadjuvant therapy and the gastroenterologist

With current treatment, survival of greater than 1 year should be anticipated for many patients with pancreatic cancer. Cure rates (5-year survival) of greater than 10% have been achieved even for unresectable disease. Obstructive jaundice is managed successfully with endoscopic placement of a plastic stent early in the evaluation of a patient with suspected regional pancreatic cancer, and a metal wall stent is reserved for patients with known 1997 AJCC stage IVB carcinoma or nonoperative patients. Relief of biliary obstruction allows improvement in liver function and more time to evaluate tumor stage accurately to determine initial treatment (see Fig. 1). A cost-effective algorithm to determine accurate stage and treatment can start with the size of the mass on initial imaging studies. EUS-guided FNA represents a significant improvement over CT scan-guided FNA to make a tissue diagnosis. Small pancreatic masses that would be resected regardless of whether an FNA is positive or negative require only an EUS evaluation to establish an early resectable stage. Tumors reliably staged as unresectable by nonoperative imaging methods including EUS are treated with chemotherapy with or without concurrent radiotherapy because median survival of these patients is 2 years in some series. Tumors can be resected after neoadjuvant chemoradiotherapy. For chronic pain or gastric outlet obstruction not responding or treatable by chemoradiotherapy, endoscopically guided celiac plexus nerve block and stenting improve the quality of life for patients with pancreatic cancer. A team approach is required to achieve the objectives of improved quality of life, prolonged survival, and possible cure for pancreatic cancer. The optimal combination and sequencing of staging methods, including EUS, specialized CT scan, MR imaging, intraoperative findings, and pathologic evaluations, would improve selection of patients for potential curative resection. Interpretations of disease stage based on each of these methods may overlap but are not identical and are operator dependent. Rather than reliance on any single standard, clinical judgment and communication among the team are paramount to providing optimal care for patients with a pancreatic neoplasm.

Neural network analysis of EUS images to differentiate between pancreatic malignancy and pancreatitis

BACKGROUND

The differentiation of focal pancreatitis and pancreatic adenocarcinoma is problematic and often resolved only by pancreaticoduodenectomy. EUS is the most sensitive imaging modality for both conditions, yet ultrasonic criteria for distinguishing the two have not been described and differentiation remains difficult. The aims of this study were to develop a self-learning computer program that can analyze EUS images and differentiate malignancy from pancreatitis, and to compare results obtained with this system with EUS interpretation by experienced endosonographers.

METHODS

Twenty-one patients with pancreatic cancer and 14 with focal pancreatitis were included. The diagnosis was confirmed histologically in all cases and each patient had undergone EUS. A single EUS image from each procedure was used for computer analysis. The results were compared with the EUS diagnosis reported at the actual procedure as well that of an endosonographer who reviewed videotapes of the procedures.

RESULTS

The software program differentiated focal pancreatitis from malignancy with a maximal 89% accuracy. With sensitivity set at 100% for malignancy, the program was 50% specific and accuracy was 80%. Sensitivity and accuracy of the endosonographer's impression at the time of EUS were, respectively, 89% and 85%. A sensitivity of 73% and accuracy of 83% were achieved with blinded interpretation of EUS videotapes.

CONCLUSIONS

Analysis of EUS images with computer software programs is feasible and compares favorably with human interpretation. The application of this technology to EUS and other imaging scenarios could be a useful adjunct to diagnostic endoscopy and warrants further investigation.