Can CA19-9 kinetics replace imaging procedures in response evaluation of patients undergoing chemotherapy for metastatic pancreatic cancer? / Kann die Kinetik des CA19-9 bei der Response-Evaluation von chemotherapeutisch behandelten Patienten mit metastasierendem Pankreaskarzinom bildgebende Verfahren ersetzen?

Abstract

Abstract Background: Response evaluation by standard imaging procedures such as computed tomography (CT) may be difficult in patients undergoing chemotherapy for advanced and metastatic pancreatic cancer. The aim of the study was to determine whether kinetics of CA19-9 levels can replace imaging procedures in evaluating the response to chemotherapy in these patients. Patients and methods: Patients with advanced or metastatic pancreatic cancer were included in the study. Patients received a combination chemotherapy consisting of gemcitabine (1000 mg m−2 d1, 8, 15) and cisplatin (50 mg m−2 d1, 15) repeated on day 29. Treatment was continued until unacceptable toxicity or disease progression occurred. CA19-9 levels were measured directly before each cytotoxic treatment cycle. CA19-9 response was defined by a ≥50% decrease in CA19-9 serum levels within two months after treatment initiation. Results: A total of 77 patients with initially elevated CA19-9 levels were included for evaluation (f/m = 26/61; stage 3/4 = 24/63). Out of 15 patients who had responded to chemotherapy regarding imaging criteria (CR 4, PR 11, OR 19.5%), 14 patients were classified as CA19-9 responders. Although 62 patients had not responded to chemotherapy by CT-imaging criteria, 29 patients fulfilled the criterion of a CA19-9 responder. The low value of CA19-9 kinetics in predicting imaging results (positive predictive value 32.5%) seems to be clinically irrelevant since CA19-9 responders, independent of imaging criteria, have a significant improvement of survival time compared to non-responders (295 days; 95%CI: 285–445 vs 174 days; 95%CI: 134–198; p = 0.022). Conclusion: CA19-9 kinetics are unable to predict tumor response regarding imaging criteria. However, the kinetic of CA19-9 in a patient undergoing chemotherapy for pancreatic cancer seems to be a reliable indicator in predicting survival.