Endoscopic Ultrasound-guided Fine Needle Aspiration and Biopsy for Cytohistological Diagnosis of Gallbladder Cancer: a multicenter retrospective study.

BACKGROUND AND AIMS: Endoscopic ultrasonography-guided fine-needle aspiration and biopsy (EUS-FNAB) is a standard diagnostic procedure for pancreatic masses but not gallbladder (GB) cancer. We aimed to investigate the efficacy and safety of EUS-FNAB for patients with suspected GB cancer (GBC).

METHODS: We analyzed data from patients who underwent EUS-FNAB for suspected GBC in three hospitals between 2010 and 2023. We calculated and compared the diagnostic performance and safety of EUS-FNAB according to characteristic factors.

RESULTS: Of 170 patients, 163 had GBC. EUS-FNAB samples were obtained from the GB in 125 patients and sites other than the GB in 45 patients. The overall sensitivity, specificity, and accuracy were 83.4%, 100%, and 84.1%, respectively. The sensitivity and accuracy for patients with GB samples were 80.8% and 81.6%, respectively, whereas those for patients without GB samples were 90.7% and 91.1%, respectively. The sensitivity and accuracy were higher with FNB needles than with FNA needles, and with ≤22-gauge needles than with 25-gauge needles. However, no significant differences were observed between the GB and lymph node (LN) samples. GB lesions <40 mm in size, wall-thickening type, fundal location, absence of extensive liver invasion, and distant metastasis were more frequent in patients without GB samples than in patients with GB samples. Four mild bleeding events were the only reported adverse events.

CONCLUSIONS: EUS-FNAB was safe and showed high diagnostic performance for patients with suspected GBC, regardless of the target site. When appropriate GB targeting is difficult, targeting the LNs would be a good strategy with comparable outcomes.