The 25-gauge EUS-FNA needle: Good for on-site but poor for off-site evaluation? Results of a randomized trial

Background: When on-site cytopathology support is not available, EUS-guided fine needle aspiration (EUS-FNA) is performed for cell-block preparation to allow off-site interpretation.

Objective: To identify the number of passes required to obtain a diagnostic cell block by using a 25-gauge needle for sampling pancreatic masses.

Design: Randomized trial.

Setting: Tertiary care hospital.

Patients: Sixty-two patients with solid pancreatic mass lesions.

Interventions: EUS-FNA was performed by using a 25-gauge needle. After establishing a preliminary on-site diagnosis, patients were randomized to 2 or 4 FNA passes for a cell block. A cell block was evaluated by a pathologist blinded to on-site interpretation for the presence of a tissue pellet, histological core tissue size, and diagnostic accuracy.

Main outcome measurements: To determine the number of passes required to obtain a diagnostic cell block with a 25-gauge FNA needle.

Results: Sixty-two patients were randomized to undergo either 2 (n = 31) or 4 (n = 31) FNA passes for a cell block. Before randomization, an on-site diagnosis was established in all 62 patients (100%). The final diagnosis was adenocarcinoma in 45 (72.6%), neuroendocrine/other tumor in 7 (11.3%), and chronic pancreatitis in 10 (16.1%). There was no difference in the presence of a tissue pellet (93.5 vs 96.8%; P = .99), the median size of the histological core (0.006 vs 0.05 mm(2); P = .12), or the presence of a diagnostic cell block (80.6 vs 80.6%; P = .99) between patients randomized to 2 or 4 FNA passes, respectively.

Limitations: Only pancreatic masses were evaluated.

Conclusions: The 25-gauge FNA needle yielded a diagnostic cell block in only 81% of patients, irrespective of whether 2 or 4 FNA passes were performed. These findings have important implications for centers without on-site cytopathology services. (Clinical trial registration number NCT01809028.).