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PTH-023 Histology, Cytology or Both for Sampling of Solid Pancreatic Masses? Prospective Evaluation of A New 22G Biopsy Needle

Introduction For solid pancreatic masses (SPM), EUS-fine needle aspiration cytology (FNA-C) has a variable diagnostic yield and sensitivity for diagnosis of malignancy, given the limited material, presence of inflammation and inherent difficulties in cytologic interpretation. Histology of formalin-fixed biopsies is simpler, cheaper and may allow extra marker studies more often. This study evaluated the ability of a new EUS biopsy needle (1) to obtain histological biopsies (FNB) with a limited number of passes; (2) to compare specimen adequacy and diagnostic sensitivity with FNA-C; (3) compare specimen quality between FNA-C and FNB. Methods Over 5 months, consecutive patients with SPM underwent EUS biopsy sampling using a standardised protocol. Patients in whom lesions were predominantly cystic, taking anticoagulants or in whom access with a 22 g needle was deemed impossible were excluded. Using a 22 g ‘Sharkcore’ needle (Medtronic, Dublin, Ireland), 4 passes were made, using slow stylet withdrawal and material expelled into Cytolyt cytology fixative (2 passes) or into formalin for histology processing. Sampling sequence was randomised (passes 1&3 into cytology with passes 2&4 into formalin, or vice versa). Pathological assessment was performed by one of 2 specialist GI pathologists using a structured proforma, to rate specimen adequacy, sample quality, diagnosis and subjective superiority. Results 43 patients were included (23 M, 20 F, mean age 66 years, range 46–83 y). One patient was excluded from analysis due to incomplete follow-up. Final diagnoses were pancreatic malignancy (35, 83.3%) and benign pancreaticobiliary disorders (7, 16.7%). Results (n = 42) are shown in Table 1:Abstract PTH-023 Table 1 Specimen adequacy (n, %) Samples rated as excellent (n, %) Sensitivity (%) Specificity (%) PPV (%) NPV (%) Accuracy (%) Overall superiority (n) FNA-C 41 (95.3) 3 86.8 100 100 44.4 90.2 4 FNB 42 (97.6) 12 92.1 100 100 57.1 92.8 28 P-value* 1.0 0.02 1.01 1.0 1.0 1.0 0.86 0.001 *Fisher’s exact test (two-tailed) In 2 cases FNA-cytology was negative for malignancy but FNB histology was positive; in contrast there were no cases where cytology was positive but histology was negative. Subjectively, FNB histology samples were scored as superior in 28 cases (66.7%), compared to FNA-C samples (4, 9.5%). In the remainder, samples were judged to be of equivalent quality (10, 23.8%). Conclusion The 22 g Sharkcore needle provides histological-quality samples in almost all cases of pancreatic or peripancreatic masses, with only 2 passes. Samples are more often superior to those obtained by cytology. This offers the prospect of shorter procedure times, easier sample processing and more reliable diagnosis. Disclosure of Interest None Declared