Monitoring of CA19-9 and SPan-1 can facilitate the earlier confirmation of progressing pancreatic cancer during chemotherapy

Background: Measurement of objective response to chemotherapy using imaging modalities is sometimes difficult in pancreatic cancer (PC). We aimed to verify whether monitoring of serum tumor markers (TMs), namely carcinoembryonic antigen, CA19-9, DUPAN-2, SPan-1, can facilitate earlier confirmation of treatment failure. Methods: Monitoring of serum TMs and computed tomography were performed every 4 weeks until progression of disease in 90 patients with PC undergoing gemcitabine therapy. In Group A (January 2006 - October 2007), we analyzed the fluctuation rates of TMs with high pretreatment positive rates, and defined the criteria of progressive disease under TM monitoring (TM-PD). In Group B (November 2007 - October 2008), we calculated the time to progression (TTP) under this TM-PD criteria, which was compared with the TTP under the RECIST criteria. Results: CA19-9 and SPan-1 had the highest pretreatment positive rates: 83% and 90%, respectively. In Group A (CA19-9, n = 38; SPan-1, n = 36), TM-PD criteria were defined as follows: fluctuation rates were >25% for a month or >10% for 2 consecutive months in CA19-9, and >10% for a month in SPan-1. In Group B (CA19-9, n = 18; SPan-1, n = 17), under these criteria, one-month earlier confirmation of treatment failure was feasible in 61% by CA19-9 and 59% by SPan-1. Furthermore, the combination could facilitate this determination in 72% (35/49), significantly better than CA19-9 alone (P = 0.004). Conclusion: Monitoring of serum CA19-9 and SPan-1 is helpful for earlier confirmation of treatment failure during gemcitabine therapy in PC.