EUS fine-needle biopsy of solid pancreatic masses with and without rapid on-site evaluation for commercial next generation genomic profiling.

Background and aims: While EUS with fine-needle biopsy (EUS-FNB) of solid pancreatic lesions with or without the use of rapid on-site-evaluation (ROSE) has high diagnostic yield, the utility of ROSE for commercial genomic analysis is unclear.

Methods: A multicenter retrospective review was conducted of consecutive patients where genomic analysis was requested from EUS-FNB of solid pancreatic lesions, performed with 22g FNB-needles. Data was collected at two academic centers, one that routinely utilizes ROSE to assess adequacy for all EUS-FNB cases (UCSF, n=44) and a second that does not utilize ROSE (Washington University, n=186).

Results: The cohort consisted of 230 patients (mean age 67.3 (SD9.8), 52.6% female). There were no significant differences between patient and tumor characteristics/location in the two groups. Adverse events were uncommon and similar between the groups (1.6% vs 0%). Adequacy for genomic evaluation was high and similar between those without and with ROSE (159/186 (85.5%) vs 39/44 (88.6%), p=0.8). Genomic analysis resulted in potentially actionable mutations in a similar number of patients without and with ROSE (18.3% vs 15.9%, p=0.82). However, compared with FNB without ROSE, FNB with ROSE required more than double the procedure time (mean (SD): 21.1 (10) vs 49.7 (20.6) min, p<0.001) and significantly higher number of median needle passes (3 (IQR 2-3) vs 4 (IQR 3-4), p<0.001).

Conclusions: While EUS-FNB with ROSE did not have significantly different adequacy for commercial genomic analysis compared to EUS without ROSE, it required significantly more procedure time and needle passes.