CA-125 AUC as a predictor for epithelial ovarian cancer relapse

The aim of the present work was to evaluate the usefulness of CA-125 normalized in time area under the curve (CA-125 AUC) to signalise epithelial ovarian cancer relapse.

Data from a hundred and eleven patients were submitted to two different approaches based on CA-125 AUC increase values to predict patient relapse. In Criterion A total CA-125 AUC normalized in time value (AUC(i)) was compared with the immediately previous one (AUC(i-1)) using the formulae AUC(i) > or = F * AUC(i-1) (several F values were tested) to find the appropriate close related increment associated to patient relapse. In Criterion B total CA-125 AUC normalised in time was calculated and several cut-off values were correlated with patient relapse prediction capacity.

In Criterion A the best accuracy was achieved with a factor (F) of 1.25 (increment of 25% from the previous status), while in Criterion B the best accuracies were achieved with cut-offs of 25, 50, 75 and 100 IU/mL. The mean lead time to relapse achieved with Criterion A was 181 days, while with Criterion B they were, respectively, 131, 111, 63 and 11 days.

Based on our results we believe that conjugation and sequential application of both criteria in patient relapse detection should be highly advisable. CA-125 AUC rapid burst in asymptomatic patients should be firstly evaluated using Criterion A with a high accuracy (0.85) and with a substantial mean lead time to relapse (181 days). If a negative answer was obtained then Criterion B should performed to confirm the absence of relapse.