Introduction
Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been widely used as a safe and effective method for obtaining samples from Solid masses around the gastrointestinal tract. It is difficult for endosonographers to determine the timing of termination of EUS-FNA. However, several reports have validated macroscopic on-site evaluation (MOSE) as safe and effective.
Aims & Methods
We performed a prospective pilot study to explore the value of MOSE in evaluating the specimen quality during magnifier-based EUS-FNA and confirm the cut-off length of visible tissue core (VTC). 79 consecutive patients who underwent EUS-FNA of solid masses around the gastrointestinal tract using 22-G needles were included in the study. After EUS-FNA, endosonographers used a special observation table to on-site evaluate all puncture specimens. Then, the specimens containing VTC were prepared into cell block and stained with haematoxylin-eosin (HE). Pathologists explored the relationship between VTC length and specimen quality. Finally, the receiver-operating characteristic (ROC) curve of the VTC length, with respect to the final diagnoses were plotted, and the accuracy of the area under the curve (AUC) for diagnostic yield was evaluated and to determine the optimal cut-off VTC length with the Youden index. The utility of optimal cut-off VTC length in diagnosis was investigated.
Results
1. In this study, EUS-FNA was performed on 93 masses in 79 patients, with a total number of needle passes of 249, including 221 needle passes (88.8%) containing VTC. The completion rate of EUS-FNA was 100% and the complication rate was 1.1%. Assisted by MOSE, the sensitivity, specificity, positive predictive value, negative predictive value and histological diagnostic rate of EUS-FNA in this study were 85.9% (73/85), 100.0% (8/8), 100.0% (73/73), 40.0% (8/20) and 87.1% (81/93), respectively. The kappa statistic indicated quite high agreement between EUS-FNA histologic diagnoses and final diagnoses (Kappa=0.511, P<0.05).
2. The pathologist scored the specimen and correlation analysis was performed by Spearman’s rank-order correlation. It is concluded that a positive correlation between specimen quality (integrity of tissue structure) and VTC length (rs=0.427, P<0.05). The ROC curve of the VTC length showed the cut-off VTC length of 7.45 mm with area under the curve of 0.838. With this cut-off level, the sensitivity and specificity of EUS-FNA were 80.8% and 66.7%, respectively.
3. Multivariate analyses of factors affecting the tissue diagnostic rate of EUS-FNA were performed. Inclusion factors were the maximum diameter of lesion, location of lesion, puncture method and the VTC length. The statistical results indicated that the VTC length ≥7.45mm and the maximum diameter of lesion were associated with the higher diagnostic rate of histopathology. However, the tissue diagnostic rate was not related to the location of lesion and puncture method.
Conclusion
1. MOSE could help endosonographers better assess specimen quality, so as to predict the specimen adequacy independently. We determined that the histological diagnostic yields were significantly improved when the VTC lengths obtained by EUS-FNA ≥7.45mm.
2. MOSE based on magnifying glass is practical for improving the specimen quality and reducing the number of needle passes when ROSE is unavailable. It is a safe, effective and economical diagnostic method for the solid masses around the gastrointestinal tract.
References
1. Iglesias-Garcia J, Dominguez-Munoz JE, Abdulkader I, et al. Influence of on-site cytopathology evaluation on the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of solid pancreatic masses. Am J Gastroenterol 2011;106:1705-10.
2. Iglesias-Garcia J, Larino-Noia J, Abdulkader I, et al. Rapid on-site evaluation of endoscopic-ultrasound-guided fine-needle aspiration diagnosis of pancreatic masses. World J Gastroenterol 2014;20:9451-7.
3. Leung Ki EL, Lemaistre AI, Fumex F, et al. Macroscopic onsite evaluation using endoscopic ultrasound fine needle biopsy as an alternative to rapid onsite evaluation. Endosc Int Open 2019;7:E189-E194.
4. Iwashita T, Yasuda I, Mukai T, et al. Macroscopic on-site quality evaluation of biopsy specimens to improve the diagnostic accuracy during EUS-guided FNA using a 19-gauge needle for solid lesions: a single-center prospective pilot study (MOSE study). Gastrointest Endosc 2015;81:177-85.
5. Ishiwatari H, Sato J, Fujie S, et al. Gross visual inspection by endosonographers during endoscopic ultrasound-guided fine needle aspiration. Pancreatology 2019;19:191-195.
Disclosure
The authors have nothing to disclose.
