Benefits of macroscopic on-site evaluation in endoscopic ultrasound-guided tissue acquisition for comprehensive genomic profiling.

Background and study aims: Matched therapy based on comprehensive genomic profiling is a potential treatment option for patients with inoperable pancreatic cancer; however, the optimal method for obtaining tissue samples suitable for comprehensive genomic profiling using endoscopic ultrasound-guided tissue acquisition remains unclear. This study aimed to determine the optimal endoscopic ultrasound-guided tissue acquisition method to obtain samples for comprehensive genomic profiling.

Patients and methods: This retrospective study included 86 consecutive patients with pancreatic cancer who underwent comprehensive genomic profiling using FoundationOne CDx (Foundation Medicine Inc.) and endoscopic ultrasound-guided tissue acquisition between June 2019 and January 2023. Macroscopic visible core length was measured using on-site macroscopic evaluation in all patients. Foundation Medicine Inc. reported analysis results categorized as passed (successful FoundationOne CDx), qualified, or failed. We investigated factors predicting successful FoundationOne CDx treatment.

Results: Needles sized 22, 20, and 19 gauge were used in 63, one, and 23 patients, respectively. The stylet slow-pull and suction techniques were performed in 43 and 41 patients, respectively. Median total macroscopic visible core length in the formalin-fixed paraffin-embedded blocks subjected to FoundationOne CDx was 41 mm. The success rate for FoundationOne CDx was 66%. Multiple linear regression analysis revealed that macroscopic visible core length independently affected successful FoundationOne CDx ( P = 0.0019).

Conclusions: In tissue specimens obtained using endoscopic ultrasound-guided tissue acquisition, macroscopic visible core length can be associated with an appropriate sample for FoundationOne CDx.