Post written by Jae Hee Cho, MD, PhD, and Seungmin Bang, MD, PhD, from the Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea.

Gallbladder (GB) cancer (GBC) is a rare but highly aggressive malignancy, often diagnosed at an advanced stage. Because most patients have unresectable diseases, accurate nonsurgical diagnosis is crucial for subsequent treatment.

Our recently accepted study in GIE evaluated the diagnostic performance and safety of EUS-guided FNA and biopsy (EUS-FNAB) in patients with suspected GBC. We retrospectively analyzed data from 170 patients across 3 tertiary care university hospitals.

Key findings

Diagnostic accuracy: The study demonstrated that EUS-FNAB achieved high diagnostic accuracy for GBC, with an overall sensitivity of 83.4%, specificity of 100%, and accuracy of 84.1%. The sensitivity and accuracy for patients with GB samples were 80.8% and 81.6%; for patients without GB samples, these values were 90.7% and 91.1%.

Comparison of needles: FNB needles showed higher sensitivity and accuracy than FNA needles (93.8% vs 60.0% [P < .001]; 94.1% vs 61.5% [P < .001], respectively). In addition, 22-gauge or thicker needles showed higher sensitivity and accuracy than 25-gauge needles (87.8% vs 70.7% [P = .012]; 88.4% vs 71.4% [P = .010]).

Adverse events: The procedure was generally safe, with a low incidence of adverse events. Only 4 mild bleeding events were reported, and there were no cases of GI perforation, bile peritonitis, or needle tract seeding.

Characteristics influencing tissue sample location: GB lesions <40 mm in size of wall-thickening type, fundal location, with an absence of extensive liver invasion, and a presence of distant metastasis were more frequent in patients who underwent EUS-FNAB without primary GB lesion than those with GB samples. These 5 characteristics suggest the presence of other easily accessible lesions, such as lymph nodes, and indicate the difficulty in targeting primary GB lesions.

Conclusion

Our study supports the use of EUS-FNAB as a safe and accurate tool for cytopathologic diagnosis in patients with suspected GBC, regardless of the target site. When appropriate GB targeting is difficult, targeting the lymph nodes would be a good strategy with comparable outcomes.

Future directions

Further prospective studies are needed to validate these findings and explore the integration of EUS-FNAB into standard diagnostic protocols for GBC. Moreover, research into the use of different needle types and gauges could further optimize the diagnostic yield and safety of this procedure.

Graphical Abstract

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