Clinicopathological Features, Recurrence Patterns, and Prognosis of Pancreatic Adenocarcinoma with Normal Serum CA19-9. A Consecutive Series of 154 Cases from a Single Institute.

backgroundSerum levels of CA19-9 correlate with recurrence and survival in patients with pancreatic adenocarcinoma; however, little is known about the features and prognosis of pancreatic adenocarcinoma with normal CA19-9 levels.

methodPatients with pancreatic adenocarcinoma (n = 806) were split into two groups with normal (≤ 37 U/mL) and elevated (> 37 U/mL) CA19-9. The clinicopathological features, survival, and recurrence patterns were compared between two groups. We also sought to identify factors that best predicted prognosis in pancreatic adenocarcinoma with normal CA19-9 levels, to assist in the selection of the most effective adjuvant treatment.

resultsPancreatic adenocarcinoma with normal CA19-9 were less likely to have lymph node metastasis, angiolymphatic invasion, intrapancreatic neural invasion, anterior serosal invasion, and invasion of the surrounding tissue/organ (distal bile duct, duodenum, or splenic artery or vein). Following propensity-score matching, pancreatic adenocarcinoma with normal CA19-9 levels (≤ 37 U/ml) were associated with significantly superior overall survival following resection. Moreover, the CA19-9 ≤ 37 U/mL group demonstrated a significantly lower rate of local recurrence (35.57% vs. 52.35%, p = 0.004), distant recurrence (42.95% vs. 60.4%, p = 0.003), and mixed recurrence (5.37% vs. 29.53%, p < 0.000) compared with the CA19-9 > 37 U/mL group. Multivariate analysis suggested that angiolymphatic invasion, lymph node metastases, and tumor size > 3 cm were independent prognostic factors for pancreatic adenocarcinoma with normal CA19-9. Survival analyses suggested that post-op chemoradiotherapy or chemotherapy were associated with more favorable outcomes.

conclusionsPancreatic adenocarcinoma with normal pretreatment CA19-9 levels (≤ 37 U/ml) were characterized by better biological characteristics, reduced rates of recurrence, and longer overall survival. Moreover, optimal adjuvant therapy should be performed after surgery.