CA 19-9 tumor marker: is it reliable? A case report in a patient with pancreatic cancer.

Pancreatic cancer is one of the most lethal malignancies affecting mankind. At the time of diagnosis, only 20% of patients are considered eligible for surgery and approximately one half of these patients undergo successful resection. For patients with locally advanced or metastatic disease, the median survival time is less than 1 year.1-4 Thus, it is crucial to diagnose or detect the recurrence of pancreatic cancer at its early stage. Serum or tissue tumor markers have been proposed for use in clinical practice in order to predict prognosis, monitor response to treatment, and help detect recurrence. Among such markers, carbohydrate antigen 19-9 (CA 19-9) is the most widely investigated. However, because CA 19-9 may be an imprecise or insufficient indicator of disease progression, treatment decisions should not be based solely on an increase of CA 19-9 levels. Here we present a case of a patient whose fluctuating levels of CA 19-9 did not reflect recurrent pancreatic malignancy.