Carbohydrate antigen 19-9 change during chemotherapy for advanced pancreatic adenocarcinoma

Radiologic assessment of tumor response in pancreatic cancer is complicated by desmoplastic reactions within or around the tumor. The objective of this study was to evaluate the correlation between a decline in carbohydrate antigen 19-9 (CA 19-9) and survival in patients with advanced pancreatic cancer who received upfront chemotherapy.

CA 19-9 serum basal values were measured in 247 patients with advanced pancreatic cancer who were enrolled in 5 consecutive trials between 1997 and 2007. Survival curves were compared among patients who had a predefined CA 19-9 nadir variation (<50%. Group 1; 50% to 89%, Group 2; or >89%, Group 3). To eliminate guarantee-time bias, survival analysis was repeated using the landmark method.

In both univariate and multivariate analysis, the basal CA 19-9 value significantly predicted survival. The median survival was 15.5 months for 34 patients who had normal basal CA 19-9 values, 11.9 months for 108 patients who had basal values between 38 U/mL and 1,167 U/mL, and 8 months for 105 patients who had basal values >1,167 U/mL. At least 1 CA 19-9 follow-up value was available for 204 patients who had baseline values greater than normal. A significant difference in overall survival was observed in univariate and multivariate analyses between Groups 1 and 2, between Groups 1 and 3, and between Groups 2 and 3. The results were confirmed using the landmark method.

In this study, baseline CA 19-9 was confirmed as an independent prognostic factor for survival, and it may be considered as a stratification factor in trials in patients with advanced pancreatic cancer. Biochemical response may be used as a complementary measure to radiologic response to provide a better assessment of chemotherapy activity and to drive treatment decisions in clinical practice.