Diagnostic Yield of Repeat Endoscopic Ultrasound-Guided Fine Needle Biopsy for Solid Pancreatic Lesions

Repeated endoscopic ultrasound-guided fine-needle biopsy of solid pancreatic lesions after previous nondiagnostic or inconclusive sampling

OBJECTIVES

Repeated endoscopic ultrasound (EUS)-guided tissue acquisition represents the standard practice for solid pancreatic lesions after previous nondiagnostic or inconclusive results. Since data are lacking, we aimed to evaluate the diagnostic performance of repeated EUS fine-needle biopsy (rEUS-FNB) in this setting. The primary outcome was diagnostic accuracy; sample adequacy, sensitivity, specificity, and safety were secondary outcomes.

METHODS

Consecutive patients undergoing rEUS-FNB for solid pancreatic lesions at 23 Italian centers from 2019 to 2021 were retrieved. Pathology on the surgical specimen, malignant histology together with ≥6-month follow-up, and benign pathology together with ≥12-month follow-up were adopted as gold standards.

RESULTS

Among 462 patients, 56.5% were male, with a median age of 68 (59-75) years, malignancy prevalence 77.0%. Tumor size was 26 (20-35) mm. Second-generation FNB needles were used in 89.6% cases. Diagnostic accuracy, sensitivity, and specificity of rEUS-FNB were 89.2%, 91.4%, and 81.7%, respectively (19 false-negative and 12 false-positive results). On multivariate analysis, rEUS-FNB performed at high-volume centers (odds ratio [OR] 2.12; 95% confidence interval [CI] 1.10-3.17; P = 0.03) and tumor size (OR 1.03; 95% CI 1.00-1.06; P = 0.05) were independently related to diagnostic accuracy. Sample adequacy was 94.2%. Use of second-generation FNB needles (OR 5.42; 95% CI 2.30-12.77; P < 0.001) and tumor size >23 mm (OR 3.04; 95% CI 1.31-7.06; P = 0.009) were independently related to sample adequacy.

CONCLUSION

Repeated EUS-FNB allowed optimal diagnostic performance after nondiagnostic or inconclusive results. Patients' referral to high-volume centers improved diagnostic accuracy. The use of second-generation FNB needles significantly improved sample adequacy over standard EUS-FNB needles.

Echoendoscopic ultrasound pancreatic adenocarcinoma diagnosis and theranostic approach: should KRAS mutation research be recommended in everyday practice?

Background

The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB).

Objectives

We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival.

Design

In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed.

Methods

The EUS-FNB samples, combined with KRAS testing using the Idylla® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC).

Results

A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation.

Conclusion

KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.

Role of Endoscopic Ultrasound in Diagnosis of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common (90%) type of solid pancreatic neoplasm. Due to its late presentation and poor survival rate, early diagnosis and timely treatment is of utmost importance for better clinical outcomes. Endoscopic ultrasound provides high-resolution images of the pancreas and has excellent sensitivity in the diagnosis of even small (<2 cm) pancreatic lesions. Apart from imaging, it also has an advantage of tissue acquisition (EUS fine-needle aspiration, FNA; or fine-needle biopsy, FNB) for definitive diagnoses. EUS-guided tissue acquisition plays a crucial role in genomic and molecular studies, which in today's era of personalized medicine, are likely to become important components of PDAC management. With the use of better needle designs and technical advancements, EUS has now become an indispensable tool in the management of PDAC. Lastly, artificial intelligence for the detection of pancreatic lesions and newer automated needles for tissue acquisition will obviate observer dependency in the near future, resulting in the wider dissemination and adoption of this technology for improved outcomes in patients with PDAC.