<p style="text-align: justify;">Markedly elevated CA 19.9 concentrations in serum are regarded as specific enough to reliably identify pancreatic cancer, even if a consistent body of literature shows CA 19.9 concentrations >1000 kU/L in a variety of benign conditions. Scarce data are, however, available on the prevalence and clinical significance of CA 19.9 values >10,000 kU/L. Here we present a case series of 18 consecutive patients admitted to our hospital in a time period of 14 months showing an enormous elevation of CA19.9 concentrations (11,568 to >100,000 kU/L), with the aim to assess the association of such concentrations with the presence of pancreatic cancer and, more in general, with tumours of the gastrointestinal system. We also tried to define whether the exact measurement of CA 19.9 concentrations in this range, which needs serial sample dilutions, is cost-effective. CA 19.9 measurements, including sample dilutions according to a defined laboratory protocol, were performed on Roche Modular EVO system. The yearly prevalence of hospitalized patients tested for CA 19.9 and with marker concentrations >10,000 kU/L was 2.9%. All recruited patients were diagnosed as malignancies: 15 had primary or secondary pancreatic cancer, two had gastric cancer, and one a cholangiocarcinoma. CA 19.9 concentrations ranged between >10,000-30,000 kU/L in 9 cases, >30,000-60,000 kU/L in two, >60,000-100,000 kU/L in three, and >100,000 kU/L in four cases, respectively. A surgical resection of the tumour was performed in five patients, independently of CA 19.9 concentrations. The median patient’s survival was <6 months. In conclusion, CA 19.9 concentrations >10,000 kU/L unequivocally identify a gastrointestinal malignancy, more frequently (~83%) a primary or secondary pancreatic cancer. Exactly measuring CA 19.9 concentrations >10,000 kU/L after multiple sample dilution does not add relevant information for patients’ prognosis and treatment.</p> |