Ca19-9 serum levels predict micrometastases in gastric cancer patients
Background: We explored the prognostic value of up-regulated Ca19-9 antigen in node negative patients as a surrogate marker for micrometastases.
Methods: Micrometastases (MM) were determined with a RT-qPCR analysis of a subgroup of thirty node-negative patients. This group was used to determine a cut-off value for the preoperative serum Ca19-9 levels as a surrogate marker for MM. A group of 187 node-negative T1 to T4 patients was selected to validate the predictive value of our Ca19-9 treshold.
Results: Patients with MM had significantly higher preoperative serum Ca19-9 values compared to patients without MM (p = 0.046). The Ca19-9 levels were found to be significantly correlated with the tumor site, tumor diameter and perineural invasion. The subgroup analysis displayed an insignificantly better five-year survival rate for patients with Ca19-9 below the treshold compared to patients with values above the cut-off. The cumulative survival for T2 to T4 node-negative patients was significantly better for patients with Ca19-9 below cut-off (p = 0,04).
Conclusions: According to our results, preoperative Ca19-9 could be used to predict a higher risk for haematogenous spread and MM in node-negative patients. But the results lack the necessary sensitivity and specificy to reliably predict MM.