The Impact of Carbohydrate Antigen 19-9 on Survival in Patients with Clinical Stage I and II Pancreatic Cancer

Background Carbohydrate antigen (CA) 19-9 is a biomarker to monitor treatment effect. A threshold to predict prognostic significance remains undefined. We evaluated the impact of CA19-9 on overall survival (OS) in patients with early-stage pancreatic cancer (PC) utilizing the National Cancer Database (NCDB). Methods The NCDB was queried from 2010 to 2014 to identify patients with clinical stage I-II PC. Patients who had undocumented pretreatment CA19-9 were excluded. Patients were stratified into two cohorts: CA19-9 < 98 U/mL and CA19-9 >= 98 U/mL, and further categorized into surgery versus no surgery. Twelve- and 24-month OS rates are reported. Results Overall, 32,382 patients (stage I: 12,173; stage II: 20,209) were included. The majority of stage I (52.1%) and II (60%) patients had CA19-9 >= 98 U/mL. Stage I-II patients with CA19-9 < 98 U/mL had improved OS rates (stage I: 67.5%, 42.6%; stage II: 59.8%, 32.8%) compared with stage I and II patients with CA19-9 >= 98 U/mL (stage I: 50.7%, 26.9%; stage II: 48.1%, 22%). Among resected stage I patients, CA19-9 <98 U/mL was associated with improved OS (< 98: 80.5%, 56%; >= 98: 70.2%, 42.8%), and a similar trend was seen in resected stage II patients (< 98: 77.6%, 49.9%; >= 98: 71%, 39.2%). Unresected stage I patients with lower CA19-9 had improved OS (< 98: 42.1%, 17.5; >= 98: 29.9%, 10%), with similar findings in unresected stage II patients (< 98: 41.1%, 15.3%; >= 98: 33.4%, 10.6%). Conclusions Our study demonstrated the prognostic value of CA19-9 in patients with clinical stage I-II PC, with a value < 98 U/mL demonstrating improved survival. Surgery significantly improved survival at 12 and 24 months irrespective of CA19-9.