Agreement on endoscopic ultrasonography-guided tissue specimens: Comparing a 20-G fine-needle biopsy to a 25-G fine-needle aspiration needle among academic and non-academic pathologists.

Background And Aim: A recently carried out randomized controlled trial showed the benefit of a novel 20-G fine-needle biopsy (FNB) over a 25-G fine-needle aspiration (FNA) needle. The current study evaluated the reproducibility of these findings among expert academic and non-academic pathologists.

Methods: This study was a side-study of the ASPRO (ASpiration versus PROcore) study. Five centers retrieved 74 (59%) consecutive FNB and 51 (41%) FNA samples from the ASPRO study according to randomization; 64 (51%) pancreatic and 61 (49%) lymph node specimens. Samples were re-reviewed by five expert academic and five non-academic pathologists and rated in terms of sample quality and diagnosis. Ratings were compared between needles, expert academic and non-academic pathologists, target lesions, and cytology versus histological specimens.

Results: Besides a higher diagnostic accuracy, FNB also provided for a better agreement on diagnosing malignancy (ĸ = 0.59 vs ĸ = 0.76, P < 0.001) and classification according to Bethesda (ĸ = 0.45 vs ĸ = 0.61, P < 0.001). This equally applied for expert academic and non-academic pathologists and for pancreatic and lymph node specimens. Sample quality was also rated higher for FNB, but agreement ranged from poor (ĸ = 0.04) to fair (ĸ = 0.55). Histology provided better agreement than cytology, but only when a core specimen was obtained with FNB (P = 0.004 vs P = 0.432).

Conclusion: This study shows that the 20-G FNB outperforms the 25-G FNA needle in terms of diagnostic agreement, independent of the background and experience of the pathologist. This endorses use of the 20-G FNB needle in both expert and lower volume EUS centers.