Endoscopic Ultrasonography Guided Fine Needle Biopsy (EUS-FNB) vs. Single-incision Needle-knife (SINK) Biopsy for Diagnosis of Upper Gastrointestinal Subepithelial Lesions
Sub epithelial lesions (SELs) of the gastrointestinal (GI) tract are commonly identified
during routine endoscopy. Most of these lesions are benign. However because there is the
potential for malignant transformation it is important to correctly identify the lesion in
order to determine if any further therapy and/or surveillance is necessary for the patient,
particularly for gastrointestinal stromal tumours (GISTs).
Obtaining a definitive diagnosis for SELs is often difficult since biopsies of the normal
overlying surface mucosal layer are typically normal. EUS-FNA is the standard method by
which a biopsy-proven diagnosis is obtained for most SEL's. However, the yield for a
definite diagnosis from EUS-FNA for SELs is often suboptimal. Recently a new biopsy method,
called "single incision needle-knife" (SINK) was introduced that may prove more useful in
determining a definitive diagnosis. Furthermore, recent advances in core biopsy needles for
EUS offer the hope for improved outcomes with EUS-guided fine-needle biopsy (FNB). However,
it remains unclear whether superior diagnostic outcomes are obtained using the new SINK
biopsy method or using new EUS-FNB core needles.
- Proportion of patients receiving a definitive histologic diagnosis for gastrointestinal SELs by single incision needle-knife biopsy (SINK biopsy) vs. EUS-guided fine needle biopsy (EUS-FNB).
- Adverse events with SINK biopsy vs. EUS-FNB
- Procedure time with SINK biopsy vs. EUS-FNB
- Proportion of patients receiving a definite OR suspicious diagnosis for gastrointestinal SELs using SINK biopsy vs. EUS-FNB
- Proportion of patients for whom a mitotic rate may be calculated for gastrointestinal stromal tumours (GISTs) using SINK biopsy vs. EUS-FNB
Subepithelial lesions of the gastrointestinal (GI) tract are commonly identified during
routine endoscopy. Most of these lesions are benign. However because there is the potential
for malignant transformation it is important to correctly identify the lesion in order to
determine if any further therapy and/or surveillance is necessary for the patient.
Leiomyoma, neural origin tumours, lipoma, duplication cyst, pancreatic rest, inflammatory
fibroid polyp, granular cell tumour are considered benign SELs. Gastrointestinal stromal
tumour, lymphoma, carcinoid, metastatic carcinoma, glomus tumour are malignant or potentially
malignant lesions. Obtaining a diagnosis for SELs is often difficult since biopsies of the
normal overlying surface mucosal layer are typically normal. Jumbo forceps biopsy,
bite-on-bite technique with conventional biopsy forceps, endoscopic ultrasound (EUS) guided
fine needle aspiration (FNA), fine needle biopsy (FNB), single incision needle-knife biopsy
(SINK), and endoscopic resection allow sampling of deeper tissue layers and may provide a
histologic diagnosis. However there are no standard biopsy methods to diagnose SELs.
Endoscopic ultrasound (EUS) is a helpful imaging diagnostic tool for the evaluation of SELs
as it is capable of assessing its size, layer of origin, and echo patterns. However, it is
not reliable enough to differentiate between benign and malignant SELs. The combination of
EUS and fine needle aspiration (FNA) allows for cytologic diagnostic accuracy of about 80%.
If a malignant tumour is suspected, tissue acquisition is important because the management
may vary based on the type of SEL.
EUS-FNA enables a small needle to be passed into the lesion of interest under ultrasound
guidance, obtaining cellular material for cytology analysis. Although previous reports show
accuracy rates for EUS-FNA for SEL that range between 72% and 90% there often is a problem
of inadequate cellular aspirates for additional immunocytochemical examination. This problem
causes a miss rate of approximately 40% for additional immunocytochemical analyses that may
be needed to reach a definitive diagnosis for GISTs, although the macroscopic appearance
alone is often sufficient. Using a larger FNA needle to perform the biopsy seems to be a
logical solution to this limitation. However, doing so has thus far not been shown to
improve the adequacy of biopsy aspirates.
For this reason, core biopsy needles (EUS-FNB) have been developed in the hopes of obtaining
core tissue for histology. The advantages of a biopsy core specimen are well known because
the evaluation of tissue architecture increase the diagnostic yield compared to cytology
obtained from FNA. In addition, a tissue core biopsy is critical to diagnose and
characterize SELs by providing higher rates of immunohistological evaluation. Recently, a
novel design core biopsy needle (Sharkcore, Medtronic) has been introduced with preliminary
data suggesting superior diagnostic performance compared to previous versions of core biopsy
needles. How this new needle performs in the diagnostic evaluation of SELs remains unclear.
Single-incision needle-knife (SINK) biopsy is an alternative diagnostic method to acquire
tissue samples. By using a conventional needle knife sphincterotome, the overlying mucosa of
SELs is opened with a single linear incision of 10 mm and tissue samples are obtained by
passing conventional biopsy forceps through the opening and deep into the tumour. According
to a preliminary study by de la Serna Higuera et al, this technique provides sufficient
tissue samples with high diagnostic yield of 92.8%. However, this biopsy method is only
possible when a visible bulge from the SEL is apparent within the lumen of the
The investigators believe this technique offers the potential to obtain more substantial
tissue samples that will be much more likely to provide a definitive diagnosis for
subepithelial tumours. In addition, it is hoped that biopsy samples obtained via SINK will be
better able to provide adequate tissue for determination of the mitotic rate of GIST tumours,
which is a major predictor of malignant risk for these lesions. However, how the SINK method
compares to the latest EUS-FNB core needles is unclear, both in terms of the diagnostic
efficacy in obtaining the diagnosis and in terms of the safety profile of doing so.
The purpose of this study is to prospectively compare the efficacy and safety of EUS-FNB
using the new SharkCore needle with SINK biopsy in patients with upper GI SELs. The results
of the study will determine which method should be performed to confirm the diagnosis for
View this trial on ClinicalTrials.gov