Aims: The aim of this study was to determine the predictive role of pretreatment carbohydrate antigen 19-9 (CA19-9) measurement and its change after one cycle of gemcitabine-based therapy for response, time to progression (TTP) and overall survival (OS).
Methods: Analyses were derived from three consecutive gemcitabine-containing phase II clinical trials between 1997 and 2004.
Results: A total of 111 patients with pancreas cancer was studied. Baseline CA19-9 concentrations were dichotomized near the median. Lower baseline CA19-9 levels were positively associated with OS (median 9.1 vs 6.1 months, P = 0.0057) and TTP (median 6.4 vs 4.2 months, P = 0.0044).The covariate adjusted hazard ratio (HR) for progression among patients with baseline CA19-9 ≥ 1000 ng/mL was HR = 1.94 (95% CI 1.24–3.02), with P = 0.0035. The covariate adjusted risk of death among patients with baseline CA19-9 ≥ 1000 ng/ml was similarly elevated: HR = 1.90 (95% CI 1.23–2.94), with P = 0.0039. Change in CA19-9 levels from baseline to the end of treatment cycle 1 did not predict objective response (P = 0.75). There was somewhat longer OS (median 8.7 vs 7.1 months) and TTP (median 7.1 vs 5.4 months) in patients with ≥50% reduction in serum CA19-9 concentrations, but this was not statistically significant (P = 0.74 and 0.81, respectively).
Conclusion: Baseline CA19-9 levels may predict survival in patients with advanced pancreas cancer. The change in CA19-9 levels determined within 1 month of the initiation of therapy did not predict treatment outcome.