ERCP-Based Cell Block: A Potential One-Stop Shop in the Management of Malignant Biliary Obstruction

Malignant biliary obstruction (MBO) typically results from cancers like pancreatic adenocarcinoma, cholangiocarcinoma, and gallbladder carcinoma, and it often presents at an advanced stage. Diagnostic tools such as ERCP and EUS-FNA are commonly used for tissue sampling, but each has limitations regarding accuracy and cost. This study aimed to compare the diagnostic accuracy and cost-effectiveness of cell block (CB) cytology collected during ERCP-guided stenting with the traditional EUS-FNA plus ERCP-guided stenting approach in patients with unresectable MBO.

This prospective observational study included 102 patients with advanced unresectable MBO who underwent both EUS-FNA and ERCP-guided stenting with CB sampling. The study evaluated the diagnostic yield of three strategies: CB alone, EUS-FNA alone, and a combination of both methods. A cost-effectiveness analysis was conducted using publicly available reimbursement rates from the public healthcare system to assess potential procedural cost savings.

The diagnostic yield for EUS-FNA (82.35%) was higher than for CB (72.54%), though the difference was not statistically significant (p = 0.23). Combining both methods increased the diagnostic yield to 93.13% (p = 0.04). CB performed better in cases with direct biliary invasion (88.23% vs. 79.41% for EUS-FNA, p = 0.01). A cost reduction of 319.17 € per case was achieved using a CB-only strategy in appropriate cases.

EUS-FNA remains superior for diagnosing extrinsic MBO, but ERCP-based CB offers a cost-effective and reliable diagnostic option, particularly for biliary tract cancers. The combination of both approaches enhances diagnostic accuracy, supporting their concurrent use in specific clinical scenarios, while optimizing costs.