Bite-on-Bite Biopsy Shows No Advantage in Biliary Stricture Diagnosis

How Does the New Biopsy Technique Impact Biliary Stricture Diagnosis?

European multicenter study finds bite-on-bite biopsy technique offers no significant advantage in diagnosing biliary strictures compared to standard sampling methods. The research, involving 89 patients across 14 centers, demonstrated comparable diagnostic accuracy rates between the two techniques, challenging assumptions about the value of deeper tissue sampling in detecting cholangiocarcinoma.

How Was the International Trial Designed and Conducted?

The international prospective trial, conducted between November 2020 and August 2022, evaluated whether the bite-on-bite biopsy (BBB) technique using digital single-operator cholangioscopy (dSOC) could improve diagnostic yield in indeterminate biliary duct strictures (IBDS). Researchers from the European Cholangioscopy Group systematically compared the diagnostic accuracy of at least four standard single biopsies with that of BBB, which theoretically allows deeper sampling of suspicious lesions. The study focused on patients with IBDS who had either inconclusive results from previous diagnostic procedures or were newly diagnosed. Using Boston Scientific's SpyGlass DS II system and SpyBite Max forceps, investigators performed both techniques in each patient to enable direct intrapatient comparison. Despite the theoretical advantages of deeper tissue sampling, BBB showed an additional diagnostic yield in only 3.4% of patients compared to standard single biopsies. The diagnostic accuracy for malignancy was 78.8% for single biopsies and 77.6% for BBB, with no statistically significant difference between the techniques. Both approaches demonstrated identical specificity (100%) with similar sensitivity rates (66.0% for single biopsies vs. 63.8% for BBB). The technical success rate was slightly higher for single biopsies (98.9%) than for BBB (96.6%), with pathologists reporting adequate tissue samples in 92.1% and 87.6% of cases, respectively.

What Challenges and Observations Emerged During the Procedure?

The investigators noted that BBB was technically more challenging to perform, particularly in distal strictures, due to scope instability and difficulty identifying the site of the first bite. "We discovered that BBB is more difficult to perform successfully than single biopsies," the researchers explained in their report. An interesting subgroup finding revealed that both techniques performed better in patients with "naïve" IBDS who had not undergone previous tissue sampling, suggesting potential value for dSOC as an initial diagnostic approach. In patients without prior ERCP sampling, single biopsies achieved 79.3% sensitivity and 86.1% accuracy, while BBB reached 75.0% sensitivity and 84.1% accuracy. This contrasted sharply with the lower performance in patients who had previously undergone tissue acquisition, where sensitivity dropped to approximately 47% for both techniques. The safety profile was favorable for both approaches, with no adverse events directly associated with BBB. Only two cases of mild post-ERCP pancreatitis and two cases of cholangitis were reported among all procedures.

Could These Findings Transform Clinical Practice and Drive Innovation?

The findings challenge current assumptions about optimal biopsy strategies for IBDS and may influence future practice guidelines. The researchers acknowledged several limitations, including lack of standardized histopathological analysis across centers and the study's focus on expert treatment centers with experienced endoscopists, which might limit generalizability to lower-volume facilities. Dr. Marjolein Leclerq, the study's lead author, commented: "While we had hypothesized that deeper tissue sampling would improve diagnostic yield, our findings suggest that the current strategy of multiple single biopsies remains appropriate for most patients with IBDS." The investigators proposed that future research should explore collecting consecutive "bites" of BBB in separate containers to determine the true added value and optimal number of consecutive biopsies at one site. They also highlighted the potential of complementary technologies such as next-generation sequencing, artificial intelligence-guided biopsies, and cryobiopsy to further enhance diagnostic capabilities in challenging biliary strictures.

Industry Context: This study arrives at a critical time for advanced endoscopic technologies, as healthcare systems worldwide seek to optimize diagnostic pathways while balancing costs and clinical outcomes. The findings suggest that more complex and potentially time-consuming biopsy techniques may not necessarily improve diagnostic yield, which could influence device manufacturers' R&D priorities. Rather than focusing solely on biopsy forceps modifications, the results point toward the potential integration of molecular diagnostics, artificial intelligence, and optical technologies with existing platforms to enhance diagnostic capabilities. For companies like Boston Scientific, the challenge remains developing cost-effective solutions that meaningfully improve clinical outcomes in this challenging patient population.

Summary

A European multicenter study involving 89 patients across 14 centers has found that the bite-on-bite biopsy technique, which theoretically enables deeper tissue sampling, offers no significant diagnostic advantage over standard single biopsy methods in evaluating indeterminate biliary duct strictures. Conducted between November 2020 and August 2022, the international prospective trial compared diagnostic accuracy of at least four standard single biopsies with the bite-on-bite technique using digital single-operator cholangioscopy. Results showed comparable diagnostic accuracy rates of 78.8% for single biopsies versus 77.6% for bite-on-bite, with identical specificity of 100% and similar sensitivity rates. The bite-on-bite technique provided additional diagnostic yield in only 3.4% of patients and proved technically more challenging to perform, particularly in distal strictures. Both methods performed better in patients without previous tissue sampling, suggesting potential value for cholangioscopy as an initial diagnostic approach. The findings challenge current assumptions about optimal biopsy strategies and may influence future practice guidelines, while highlighting the need for complementary technologies such as next-generation sequencing and artificial intelligence to enhance diagnostic capabilities in challenging biliary strictures.