CA 19-9 response as an early indicator of the effectiveness of gemcitabine in patients with advanced pancreatic cancer

Background: The CA 19-9 decline 8 weeks after gemcitabine administration has been shown to be a useful prognosticator of survival in patients with pancreatic cancer. We assessed the prognostic value of changes in CA 19-9 levels 4 weeks after treatment initiation on overall survival ( OS) and time to progression (TTP). Methods: We evaluated 72 patients who received gemcitabine for advanced pancreatic cancer. The serum CA 19-9 level was measured routinely at baseline (CA 19-9_Pre) and after the first (4 weeks; CA 19-9_A1) and second (8 weeks; CA 19-9_A2) courses. CA 19-9 responses were categorized into quartiles using the proportional change in CA 19-9. Results: The rates of decrease in CA 19-9_A1 and CA 19-9_A2 were strongly correlated with each other (r = 0.8981, p < 0.0001). Multivariate analysis revealed that an early CA 19-9 response was prognostic of OS and TTP in addition to CA 19-9_Pre and performance status. Compared with the first quartile of an early CA 19-9 response, hazard ratios for the second, third and fourth quartiles were 0.91 (95% confidence interval, CI, 0.59-1.34), 0.71 (95% CI, 0.45-1.08), and 0.63 (95% CI, 0.41-0.94) for TTP, respectively (p for trend = 0.002), and 0.98 (95% CI, 0.61-1.49), 0.68 (95% CI, 0.40-1.08) and 0.79 (95% CI, 0.50-1.21) for OS (p for trend = 0.036). Conclusion: CA 19-9 response after the first course of gemcitabine was a prognosticator of OS and TTP in patients with advanced pancreatic cancer. Copyright (C) 2008 S. Karger AG, Basel.