Importance of Normalization of CA19-9 Levels Following Neoadjuvant Therapy in Patients With Localized Pancreatic Cancer

OBJECTIVE:Carbohydrate antigen 19-9 (CA19-9) is a prognostic marker for patients with pancreatic cancer (PC), but its value as a treatment biomarker is unclear. SUMMARY BACKGROUND DATA:Although CA19-9 is an established prognostic marker for patients with PC, it is unclear how CA19-9 monitoring should be used to guide multimodality treatment and what level of change in CA19-9 constitutes a meaningful treatment response. METHODS:CA19-9 measurements at diagnosis (pretx), after completion of all planned neoadjuvant therapy (preop), and after surgery (postop) were analyzed in patients with localized PC who had an elevated CA19-9 (≥35 U/dL) at diagnosis. Patients were classified by1) quartiles of pretx CA19-9 (Q1-4); 2) proportional changes in CA19-9 (ΔCA19-9) after the completion of neoadjuvant therapy; 3) normalization (CA19-9