Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB): past, present, and future

Abstract

Endoscopic ultrasound (EUS) is a combination of endoscopy and intraluminal ultrasonography. EUS also enables ultrasonographic images of high resolution to be obtained. However, whether a lesion is malignant or benign cannot be diagnosed solely from the findings of EUS. Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) was developed to enhance the diagnostic capabilities of EUS by providing additional pathological findings. Though more than 10 years have passed since EUS-FNAB was first used for pancreatic disease, EUS FNAB has not been widely accepted in Japan. This may be due to the technical difficulties, relatively low sensitivity for the detection of malignancies, and Japanese gastroenterologists' and surgeons' inherent conservative way of thinking. We describe here a short history of EUS-FNAB, with details of technical tips, current indications and contraindications, diagnostic accuracy, and complications. The clinical utility of EUS-FNAB has been gradually understood and EUS-FNAB procedures have been increasing in number in Japan. So in the near future, EUS followed by EUS-FNAB will be routinely performed in the same manner as gastrointestinal endoscopy, followed by biopsy under direct vision. Also, therapeutic EUS procedures, such as EUS-guided celiac plexus neurolysis, pancreatic tumor ablation, drainage of pancreatic pseudocysts, and the development of an anastomosis may become feasible as less invasive and safer techniques than those used at present.

Characteristics of Small Pancreatic Carcinoma: Neural Invasion is Associated with Tumor Recurrence

“…Maguchi et al [13] reported that the tumor detection rate of TS1 pancreatic carcinoma (≤2 mm) was 100%. Diagnosis by EUS-guided fine needle aspiration (EUS-FNA) at the time of tumor detection had a sensitivity of 85% to 94%, a specificity of 100%, and an accuracy of 95% [14] [15]. However, we should keep in mind that the accuracy would be lower for tumors ≤ 1 mm [16].…”

Pancreato-Biliary Cancers – Diagnosis and Management

“…Apart from biopsy of the primary tumour, it also has the ability to biopsy lymph nodes, liver lesions and ascitic fluid, which is critical in accurate staging and avoiding unnecessary resection (Figure 2). For pancreatic head lesions, the possibility of seeding is eliminated, as the needle track is included in the resection specimen (Yamao et al, 2005). In contrast, for lesions in the pancreatic body and tail, where the needle track is not resected, the risks and benefits of pre-operative biopsy should be carefully assessed on an individual basis.…”

Small pancreatic lesions: Is there need for EUS-FNA preoperatively? What to do with the incidental lesions?

“…Yamao et al [17] reported the results of biopsies by ERCP and EUS-FNA in operated patients with small pancreatic cancer less than 2 cm in diameter (TS1); the cancer-positive rate was 50 %(4/8) in the use of ERCP and 100 %(2/2) in the use of EUS-FNA. We have investigated the results of transpapillary biopsy/cytology in our operated patients with TS1; the cancer-positive rate was 56 %(10/18).…”

“…Thus, FNA negative for cancer will not exclude the suspected diagnosis of cancer and the patient will be explored anyway. In addition, the risk of tumor seeding by EUS-FNA is strongly stressed in the opinions against the indication of this approach, especially in Japan [17]. It has not fully been determined whether tumor seeding occurs with EUS-FNA.…”

“…According to this principle, EUS-FNA is currently indicated for pancreatic mass lesions for (1) histological evidence required for chemotherapy and/or radiation therapy, (2) differential diagnosis between localized pancreatitis and pancreatic cancer which shows an atypical imaging pattern and/or is negative for biopsy/ cytology by transpapillary approach, and (3) tumor staging in a patient with a small amount of ascitis or lymph node swelling [17]. However, the role of EUS-FNA in patients suspected of having pancreatic cancer that appears to be respectable on imaging studies especially small lesion is controversial.…”