Bespoke Circulating Tumor DNA Testing for Diagnostic Resolution, Disease Surveillance, and Treatment Monitoring in Hepatopancreatobiliary Malignancies: A Real-World Experience

PURPOSE: Hepatopancreatobiliary (HPB) cancers-including hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), pancreatic ductal adenocarcinoma (PDAC), and gallbladder cancer-are aggressive malignancies with limited treatment options and poor prognosis. The emergence of personalized liquid biopsy technologies, particularly bespoke circulating tumor DNA (ctDNA), offers new opportunities for improving clinical management. Traditional methods like imaging and tumor markers may miss early recurrence or evolving disease. This study explores the real-world application of ctDNA in HPB cancers, focusing on its use for surveillance, diagnostic clarification, treatment monitoring, and recurrence detection. METHODS: We retrospectively analyzed the use of a personalized ctDNA assay (Signatera, Natera) in 54 patients with HPB cancers at a single academic cancer center. The cohort included PDAC (22/54), HCC (11/54), and CCA (21/54). ctDNA was assessed longitudinally for surveillance, treatment monitoring, or diagnostic clarification. Concordance with imaging and tumor markers, as well as lead time to recurrence detection, was descriptively analyzed. RESULTS: ctDNA was evaluable in 37/54 patients (84.6%), with ctDNA positivity in 22/37 (59.5%). Success rates by tumor type were 16/22 (72.7%) in PDAC, 10/11 (90.9%) in HCC, and 11/21 (52.4%) in CCA. ctDNA concordance with imaging was observed in 69/85 assessments (72.6%) and with tumor markers (carbohydrate antigen 19-9 or alpha fetoprotein) in 39/95 (41%). Clinical applications included disease surveillance (21/54, 38.9%), treatment monitoring (24/54, 44.4%), and diagnostic clarification (16/54, 29.6%). In patients with recurrence, ctDNA detected disease before imaging in several cases, with a median lead time of 28 days (range, 1 month to 7 months). CONCLUSION: Personalized ctDNA testing demonstrated meaningful utility across HPB cancers, enabling early recurrence detection and guiding clinical decision making as a complementary tool in multidisciplinary care.