Fine-Needle Aspiration Biopsy of Pancreatic Masses: Failure Factors

Objectives: The main objective of this work is to determine the factors affecting the failure rate of pancreatic aspiration cytology, in particular the size, location, and nature of the mass as well as the size of the needle, the aspiration site, the number of passages, and realization of Fanning. Materials and methods: This is a retrospective study conducted in the EFD-HGE department at Ibn Sina Hospital in Rabat from March 2017 to May 2023. 138 patients with a solid or cystic pancreatic mass on imaging were included. A video-linear Pentax-type echoendoscope was used with needles of different gauges: 19G, 20G, 22G, and 25G. Statistical analysis was performed using R software and the level of significance was set at p < 0.05. Results: The sex ratio F/M was 1.35. The average age was 59 years old. The average tumor size was 40.5 mm. Fine needle aspiration (FNA) under ultrasound-endoscopy (EUS) was positive in 70% of cases: adenocarcinoma in 60% of cases, chronic pancreatitis in 9.33% of cases, neuroendocrine tumor in 8% of cases, solid and pseudo-papillary tumor of the pancreas in 4% of cases, mucinous cystadenoma with low-grade (LGD) in 1.33% of the cases, an intraductal papillary mucinous neoplasm (IPMN) in 2.66% of the cases, pancreatic tuberculosis in 1.33% of the cases. Normal pancreatic parenchyma without signs of malignancy in 13.33% of the cases. The failure rate of pancreatic fine-needle aspiration was estimated at 30% of cases (inconclusive result). By univariate analysis, we demonstrated that the risk of having an inconclusive fine needle aspiration increases on the one hand by the location of the mass at the head of the pancreas (p = 0.02), the presence of a cystic component (p = 0.01), the infiltrating character of the mass (p = 0.01), and on the other hand by the absence of Fanning (p = 0.03). However, this study did not show a significant correlation with the other factors, in particular the size of the mass, the size of the needle, the site of fine-needle aspiration, and the number of passages. No complications were noted. Conclusion: The failure rate of fine-needle aspiration biopsy was 30%. We demonstrated that it increases by the location of the mass at the head of the pancreas (p = 0.02), the presence of a cystic component (p = 0.01), the infiltrating character of the mass (p = 0.01), and the absence of fanning. An additional study with a larger sample or a multicenter study seems necessary to confirm our results.