EUS-FNA wet technique for the pre-operative diagnosis of 31 solid pancreatic tumors: Pisa experience

Objectives: EUS-FNA is an established procedure for obtaining a correct preoperative diagnosis of pancreatic lesions which is often indispensable to guide the right treatment. FNA wet technique relies on pre-flushing the needle with saline instead of the air column used in the dry technique. The aim of this study was to evaluate wet EUS-FNA technique with 19 and 22 G needles. Methods: between May 2016 and January 2017, 31 consecutive patients underwent EUS-FNA for pancreatic lesions at our Interventional Endoscopy Unit. Macroscopic on-site quality evaluation was performed and if a visible core was available, it was placed in formalin for histologic examination. Cellularity was assessed using a 4-point scale (0=no cells to 3=highly cellular). Specimen adequacy was graded on a 2-point scale (0=not sufficient, 1=sufficient to make a diagnosis). The final diagnosis was based on pathological examination of the resected specimen for patients underwent surgery (8/31; 25.81%) while on a minimum follow up of 36 weeks in absence of surgical treatment (23/31; 74.19%): lesions spontaneously resolved without signs of deterioration were considered as benign; lesions showed enlargement, metastasis or malignant symptoms were considered as malignant. Results: Patient median age was 63.03±11.98 years. Lesions were located in pancreatic head in 17/31 (54.8%), body/tail in 11/31 (35.5%) and uncinate process in 3/31 (9.7%). The mean size of lesions was 4.29±1.56 cm. The cytological diagnosis was pancreatic adenocarcinoma in 24 (77.4%) cases, GI stromal tumor in 1 (3.2%) case and was negative for malignancy in 6(19.4%)cases. 22 G needles was used in 10/32 procedures, 19 G in 22/32. In 31/32(97%)cases with adequate specimens, cellularity score was 1 in 6 (19.4%) cases, 2 in 10 (32.3%) and 3 in 15 (48.4%) cases. Only 2 cases resulted false negatives. No significant differences were found between 19G and 22G needles in terms of number of passes (19G 3.30 vs 20G 3.4), adequacy (19G 90% vs 22G 100%) and cellularity of the sample (19G 2.0 vs 22G 2.41), as well as in ability to obtain a correct diagnosis (19G 90.0% vs 22G 94.5%). No adverse events occurred. Wet EUS-FNA technique had sensitivity 92.59%, specificity 100%, positive predictive value 100%, negative predictive value 66.67% and diagnostic accuracy 93.55%. Conclusion: wet EUS-FNA technique with 19 and 22 gauge needles, showed a high performance in terms of adequacy and cellularity of the sample as well as in obtaining a correct diagnosis.