Multicenter retrospective cohort study of Duke pancreatic monocolonal antigen type 2 for monitoring CA 19-9 nonexpressor pancreatic cancer

Approximately 5% to 10% of patients with pancreatic cancer are CA 19-9 nonexpressors (≤ 2 U/mL), leaving them without established biomarkers for treatment monitoring. A retrospective cohort study at 9 Japanese centers evaluated Duke pancreatic monoclonal antigen type 2 (DUPAN-2) as a surrogate biomarker for monitoring treatment response in patients with CA 19-9 nonexpressor pancreatic cancer. In this cohort study of 2418 patients with resected pancreatic cancer between 2013 and 2018, 185 (7.7%) were classified as CA 19-9 nonexpressors. Nonexpressors and expressors showed comparable overall survival (aHR 1.10; 95% CI 0.89-1.37). DUPAN-2 dynamics in CA 19-9 nonexpressors mirrored CA 19-9 patterns in expressors. Achieving normal DUPAN-2 levels (≤ 150 U/mL) was associated with significantly improved survival both after neoadjuvant therapy and after resection. The authors conclude that DUPAN-2 monitoring may provide biomarker-guided treatment assessment for CA 19-9 nonexpressor pancreatic cancer patients.