Circulating tumor DNA for recurrence monitoring following resection for pancreas adenocarcinoma.

e16365 Background: Detecting early recurrence among patients with resected pancreatic cancer may facilitate earlier treatment and better outcomes for patients with resected pancreatic ductal adenocarcinoma (PDAC). Circulating tumor DNA (ctDNA) has shown promise as a tumor-specific biomarker for PDAC but has not yet entered routine clinical use. This study aims to conduct analytical and clinical validation of Signatera ctDNA profiling to predict recurrence in patients with PDAC. Methods: A retrospective IRB-approved protocol evaluating the use of Signatera ctDNA testing among patients who underwent resection at Northwell Health during 2019-2023. The utility of ctDNA status to predict PDAC recurrence during follow-up was assessed using cox regression. Results: There were 91 ctDNA tests among 24 patients. With a median follow-up of 15 months, recurrence was observed in 38% (9/24) of patients and 8 patients died. Among patients with recurrence, most of them had positive ctDNA before showing signs of recurrence on the imaging (6/9, 66.7%) with mean lead time of 116 days, while 2 of them had positive ctDNA after recurrence and one patient never had positive ctDNA. At the time of recurrence, eight patients had elevated CA19-9, while two patients with normal CA19-9 had positive ctDNA. The median recurrence-free survival (RFS) was 23 months (95% CI, 11-not reached). Patients with detectable preoperative ctDNA had significantly decreased median RFS (14 months; 7 of 10 (70%) recurred) when compared with patients negative for ctDNA not reached; 2/14 (14.3%) recurred; P= 0.005). In multivariable Cox model after adjusting for potential risk factors, detection of ctDNA was associated with RFS. (table). Conclusions: Signatera ctDNA profiling identified relapse earlier than imaging for most patients. These results suggest the potential for a prospective trial evaluating early treatment interventions in this deadly disease to improve survival rates. [Table: see text