Purpose: The role of carbohydrate antigen 19-9 (CA19-9) kinetics in patients with biliary tract cancer (BTC) receiving chemotherapy remains to be elucidated.
Methods: A total of 185 advanced or recurrent BTC patients receiving a first line chemotherapy between January 2006 and March 2016, were retrospectively studied. Serum CA19-9 was measured at baseline and after two cycles of chemotherapy, and patients were categorized based on CA19-9 response: CA19-9 decrease group (≥ 30% decrease), stable group (< 30% decrease and < 20% increase) and increase group (≥ 20% increase). The associations of CA19-9 response with radiological tumor response, progression-free survival (PFS) and overall survival (OS) were investigated.
Results: There was a statistically significant association between CA19-9 response and radiological tumor responses (p < 0.001). The median PFS and OS were significantly different among three groups according to CA19-9 response: PFS of 8.0, 5.7 and 3.5 months in CA19-9 decrease, stable and increase groups (p < 0.001) and OS of 18.8, 16.0 and 7.5 months in CA19-9 decrease, stable and increase groups, respectively (p < 0.001). Multivariate analyses showed that CA19-9 response was prognostic both of OS and PFS in addition, to CA19-9 at baseline, and performance status.
Conclusion: CA19-9 kinetics after the first two cycles of a first line chemotherapy was a prognostic factor for OS and PFS in patients with advanced and recurrent BTC.
Keywords: Biliary tract cancer; Carbohydrate antigen 19-9; Chemotherapy; Prognostic factors; Retrospective study.