Diagnostic Performance and Safety of Endoscopic Ultrasound-Guided Fine-Needle Biopsy (EUS-FNB) Under Conscious Sedation for Small Solid Pancreatic Lesions (<20 mm): A Retrospective Cohort Study

Background/Objectives: The diagnostic evaluation of small (<20 mm) solid pancreatic lesions (SPLs) remains technically challenging, and most available EUS-FNB data derive from cohorts performed under deep sedation or heterogeneous sedation protocols. This study evaluated the diagnostic performance, feasibility, and safety of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) performed under standard conscious sedation in consecutive eligible patients with SPLs < 20 mm. Methods: This was a single-center retrospective analysis of a prospectively maintained database including 114 patients with SPLs < 20 mm who underwent EUS-FNB under conscious sedation between January 2021 and December 2024. Procedural characteristics, histologic adequacy, diagnostic accuracy, repeated procedures, and adverse events were collected. Index diagnostic accuracy was calculated on completed index procedures; procedures aborted because of intolerance were analyzed as sedation failures and included in the safety and cumulative analyses. Variables associated with tissue core adequacy were assessed in an exploratory univariate analysis. Results: The mean target lesion size was 14.2 ± 4.3 mm, and 31 lesions (27.2%) were sub-centimetric (<10 mm). A 22-gauge needle was used in 98.2% of cases, a Franseen-tip needle in 80.4%, and at least two passes were performed in 87.5%. Among the 112 completed index procedures, histologic adequacy was 93.8% (105/112, 95% CI 87.7–96.9) and diagnostic accuracy was 91.1% (102/112; 95% CI 84.3–95.1), increasing to a cumulative accuracy of 97.4% (111/114) after targeted repeat procedures. Index accuracy was 93.5% (29/31) for lesions < 10 mm and 90.1% (73/81) for lesions of 10–19 mm (p = 0.724). Counting the three repeat procedures performed with anesthesiology support as failures of the conscious sedation pathway, cumulative accuracy under conscious sedation alone was 94.7% (108/114). Sensitivity, specificity, PPV and NPV of the index EUS-FNB for malignancy were 92.5%, 100%, 100% and 73.1%, respectively. No severe intraprocedural adverse events occurred; two index procedures (1.8%) were aborted because of intolerance under conscious sedation and required anesthesiology support, and two mild, self-limiting cases of acute pancreatitis (1.8%) occurred after the procedure. In the exploratory analysis, performing at least two needle passes was the only variable associated with sample adequacy (p = 0.041), although this finding was based on only seven inadequate samples. Conclusions: EUS-FNB under conscious sedation appears feasible, with high diagnostic yield and a low rate of adverse events, in consecutive eligible patients with small SPLs, including sub-centimetric targets. These findings support a pragmatic real-life workflow based on careful patient selection, adequate monitoring, modern FNB needles, macroscopic core assessment, and consideration of at least two passes whenever feasible (a hypothesis-generating finding), with ROSE or anesthesiologist support reserved for selected unresolved or poorly tolerated cases. Prospective comparative studies are needed before concluding equivalence with propofol-based deep sedation or systematic anesthesiologist-directed care.