Serum CA19-9 Response to Neoadjuvant Therapy Predicts Tumor Size Reduction and Survival in Pancreatic Adenocarcinoma

INTRODUCTION: Optimal cut-offs for CA19-9 response after neoadjuvant therapy (NT) for pancreatic adenocarcinoma (PDAC) are not well characterized. This study aims to analyze the relationship of serum CA19-9 with other markers of response and identify thresholds correlating to outcomes. METHODS: Retrospective review of resected PDAC patients from 2010 to 2017 at an academic tertiary referral center. RESULTS: Two hundred and fifty subjects entered the analysis. Normalization and multiple cut-off points for CA19-9 response were assessed. Normalization was not associated with improved survival (35.17 vs 29.43 months; p=0.173). While a response ≥45% was associated with longer survival (35 vs 20 months; p=0.018), a response ≥85% was optimal (55.7 vs 25.97 months; p