13 months, P<0.04) (50-52). Given the half life of CA 19-9 is approximately 14 hours, those authors suggested that post-operative CA 19-9 serum levels should be measured 4-6 weeks selleck catalog following surgery and that patients with elevated levels are likely to harbor residual tumor or sub-clinical metastases. In summary, postoperative normalization Inhibitors,research,lifescience,medical or a downward trend of the CA 19-9 serum level following pancreatic resection is associated with prolonged survival whereas

elevated or failure of the CA 19-9 to decrease following pancreatic resection reflects residual disease or occult metastasis and portends a poor survival. Utility of CA 19-9 serum levels to assess response to chemotherapy in pancreatic cancer patients Most patients with pancreatic cancer require chemotherapy and/or radiation, either in the neo-adjuvant setting to improve resectability or treat suspected micro-metastasis, or in the adjuvant setting for locally advanced disease, high grade tumor and when vascular invasion or lymph Inhibitors,research,lifescience,medical node metastases are present. Whether

serum CA 19-9 levels can Inhibitors,research,lifescience,medical be used as a surrogate marker of response to chemotherapy has been studied in a variety of clinical Dasatinib molecular weight settings (41,44,53-64). Willett et al. measured CA 19-9 serum levels in 42 resectable pancreatic cancer patients receiving neoadjuvant treatment with 5-flourouracil and external beam radiation prior to planned pancreaticoduodenectomy. Among 10 patients with an increased CA 19-9 serum level following treatment, 9 (90%) had distant

metastases or local Inhibitors,research,lifescience,medical tumor progression. In contrast, only 6 of 29 patients (21%) with a declining CA 19-9 serum level after neo-adjuvant chemo-radiotherapy had metastases or local tumor progression on restaging CT scan or at laparotomy. Whether the CA 19-9 serum level increased or decreased during treatment, correlated significantly with disease progression (P=0.009) (65). Katz et al. studied 119 patients with pancreatic cancer who were treated with neoadjuvant chemotherapy followed by pancreaticoduodenectomy. These authors found that a post-treatment Inhibitors,research,lifescience,medical CA 19-9 serum level of <37 U/mL had an 86% PPV for successful completion of the pancreatic resection, and a NPV of only 33%. Post-treatment Cilengitide CA 19-9 serum levels <61 U/mL also had a high 93% PPV but a diminishing 28% NPV in regards to predicting successful completion of pancreaticoduodenectomy among resectable patients (49). Although post-treatment CA 19-9 serum levels in the above mentioned study had a high PPV in regards to likelihood of resectability following neo-adjuvant chemotherapy, the low NPV highlights the importance of re-staging radiographic evaluation as well as laparoscopy prior to surgical exploration (34,49). Several authors have reported on the use of CA 19-9 serum level trends to assess chemotherapy response using such definitions as ≥20% or ≥50-75% decline in CA 19-9 serum levels within the first 6-8 weeks of treatment.