CA 19-9 tumour-marker response to chemotherapy in patients with advanced pancreatic cancer enrolled in a randomised controlled trial.

Background: Several studies in patients undergoing chemotherapy for advanced pancreatic carcinoma have linked a decrease in the concentration of the tumour marker carbohydrate antigen (CA) 19-9 to lengthened survival. The aim of this study was to test the hypotheses that an early decrease in baseline serum CA 19-9 concentration (on day 42, after two cycles of chemotherapy) by at least 50% is associated with lengthened survival, and that a decrease in CA 19-9 concentration of at least 50% from the baseline concentration to the lowest value measured at any time during treatment (nadir) is of prognostic significance, enabling its use as a surrogate endpoint for survival.

Methods: CA 19-9 serum concentration was measured at baseline and every 3 weeks thereafter in patients with histologically proven advanced pancreatic carcinoma enrolled in a randomised trial of gemcitabine versus gemcitabine plus capecitabine.