Impact of trimodality sampling on detection of malignant biliary strictures compared with patients with primary sclerosing cholangitis

Background and Aims: Malignant biliary strictures can be difficult to diagnose, with up to 20% considered indeterminate after initial tissue sampling. This study aimed to determine the performance characteristics of transpapillary biopsy sampling (TPB) and fluorescence in situ hybridization (FISH) in isolation or in combination with standard brush cytology (BC) in patients who received trimodality sampling for biliary strictures. Methods: This single-center retrospective cohort study included patients with biliary strictures undergoing ERCP with trimodality sampling between September 2014 and April 2019. Performance characteristics for each diagnostic test alone and in combination were calculated. Results: Two hundred four patients underwent trimodality biliary sampling, including 104 (51.0%) with malignancy. The diagnostic sensitivity for malignancy with BC (17.3%) significantly improved with dual modality (BC+FISH, 58.7%; BC+TPB, 40.4%) or trimodality sampling (68.3%; P < .001 for all comparisons). Trimodality sampling improved diagnostic sensitivity for malignancy compared with BC+FISH (P = .002) and BC+TPB (P < .001). There was no statistically significant difference in the sensitivity of trimodality sampling in detecting cholangiocarcinoma (79.7%) compared with pancreatic cancer (62.5%; P = .1). Among 57 patients with primary sclerosing cholangitis (PSC), the sensitivity of detecting biliary malignancy (n = 20) was 20% for BC and significantly improved with the addition of FISH (80%; P < .001) but not with TPB (35.0%; P = .25). Trimodality sampling did not further improve diagnostic sensitivity (85%) over BC+FISH (80%) for malignancy in the setting of PSC (P = 1). Conclusions: Trimodality sampling improves the diagnostic sensitivity for the detection of malignant biliary strictures with no significant difference in sensitivity for cholangiocarcinoma compared with pancreatic cancer. However, in patients with PSC, trimodality sampling was not superior to BC+FISH.

Automated summary

This study determined the performance characteristics of transpapillary biopsy sampling and fluorescence in situ hybridization in combination with standard brush cytology for diagnosing malignant biliary strictures. The findings suggest that trimodality sampling improves the diagnostic sensitivity for malignancy, but it is not superior to BC+FISH in patients with primary sclerosing cholangitis.