Tumor Cell Count and Total Cell Count as Surrogate Indicators of Comprehensive Genomic Profiling Success in Pancreatic Cancer Specimens Collected by Endoscopic Ultrasonography‐Guided Tissue Acquisition

OBJECTIVES: We aimed to establish the tumor cell count and total cell count as surrogate criteria on the basis of the tissue area of biopsy specimen by endoscopic ultrasound-guided tissue acquisition (EUS-TA) for comprehensive genomic profiling (CGP) in pancreatic cancer. METHODS: Samples from 114 patients with unresectable pancreatic ductal adenocarcinoma were analyzed. Tumor cells were visually counted, and total cells were quantified with imaging software. Receiver operating characteristic curves determined optimal cutoffs for achieving DNA yield ≥ 200 ng using the OncoGuide NCC Oncopanel. RESULTS: Thresholds of 2300 tumor cells (AUC 0.653, 95% CI 0.552-0.750) and 5923 total cells (AUC 0.671, 95% CI 0.565-0.778) were identified. For ≥ 2300 tumor cells, sensitivity was 48.7% and specificity 91.2%, with a positive predictive value (PPV) of 92.9%. For ≥ 5923 total cells, sensitivity was 52.5% and specificity 82.4%, with a PPV of 87.5%. A clinically practical threshold of 6000 total cells yielded a sensitivity of 48.8%, a specificity of 82.4%, and a PPV of 86.7%. CONCLUSION: Tumor cell counts ≥ 2300 and total cell counts ≥ 6000 may serve as surrogate criteria for tissue area to determine EUS-TA specimen suitability for CGP in pancreatic cancer. Given that tumor cell count is a more biologically relevant indicator, total cell count should be used as a supplementary indicator.