CA 19-9 as a Predictor for Response and Survival in Advanced Pancreatic Cancer Patients Treated With Chemoradiotherapy

Purpose: To investigate the significance of carbohydrate antigen 19-9 (CA 19-9) levels for predicting response and survival in pancreatic cancer (PC) treated with concurrent chemoradiotherapy. Methods and Materials: We retrospectively reviewed data from 69 patients with PC between 1999 and 2005. All patients had elevated CA 19-9 levels before treatment. CA 19-9 levels (pre- and posttreatment CA 19-9) and their decline were analyzed for radiologic response and overall survival. Results: Seventeen patients (25%) had a 50% or greater reduction in tumor size within 3 months of chemoradiotherapy (1 complete response, 16 partial responses). CA 19-9 decline was significantly correlated with radiologic response (p = 0.03). The median survival time (MST) was 12 months (range, 4-48 months), and 1-year survival rate was 44%. Pretreatment CA 19-9 > 1,200 U/mL (MST, 13 vs. 8 months; p = 0.002), posttreatment CA 19-9 >100 U/mL (MST, 17 vs. 10 months; p = 0.0003), and CA 19-9 decline ≤40% (MST, 13 vs. 10 months; p = 0.005) were the strongest and most unfavorable prognostic factors. In addition, patients with multiple unfavorable CA 19-9 levels had significantly worse outcomes than those without. Conclusions: CA 19-9 decline shows a correlation with radiologic response. The combination of pretreatment CA 19-9 >1,200 U/mL, posttreatment CA 19-9 >100 U/mL, and CA 19-9 decline ≤40% may possibly serve as a surrogate marker for poor survival in advanced PC receiving chemoradiotherapy