Background: Serum levels of CA 19-9 correlate with survival among patients with pancreatic cancer treated with surgery or radiation therapy. In addition, CA 19-9 responses have been shown to predict for a better prognosis among patients with advanced disease treated with chemotherapy. The present study evaluates the predictive role of CA 19-9 pretreatment levels and response among patients treated with gemcitabine.
Methods: We retrospectively identified 28 patients with advanced pancreatic cancer and baseline elevations of CA 19-9 (> 37 U/mL) who were treated with single agent gemcitabine. CA 19-9 response was defined as a > or = 50% decline at any time after treatment. Survival was estimated with the Kaplan-Meier method, and curves were compared with the log-rank test.
Results: Eleven patients (39%) had a CA 19-9 response. The median survival of responding patients was longer than that of non-responding patients (13.8 vs 8 mo, p = .0272). When pretreatment CA 19-9 levels were analyzed, patients who had CA 19-9 below the median for the entire sample (1212 U/mL) lived significantly longer than patients with a CA 19-9 above the median (14.9 vs 7.4 mo, p = .0013). On multivariable analysis, pretreatment CA 19-9 level was an independent, and stronger predictor of survival (p = .0005) than CA 19-9 response (p = .0497). Other variables were not associated with survival.
Conclusions: CA 19-9 may be a useful adjunct to response evaluation is this setting. In addition to CA 19-9 responses, prechemotherapy levels of this marker seem to have strong prognostic significance.