Usefulness of CA125 and its kinetic parameters and positron emission tomography/computed tomography (PET/CT) with fluorodeoxyglucose ([18F] FDG) in the detection of recurrent ovarian cancer

Abstract

Background and objective

To assess the usefulness of cancer antigen 125 (CA125) serum levels and kinetic values, velocity (CA125vel) and doubling time (CA125dt), as well as fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT), in the detection of ovarian cancer recurrence. To assess the optimal cut-off for CA125, CA125vel and CA125dt to detect relapse with [¹⁸F]FDG-PET/CT.

Material and methods

A retrospective analysis was performed of 59 [¹⁸F]FDG-PET/CT (48 patients) for suspected recurrence of ovarian cancer. Receiver operating characteristic (ROC) curves were plotted and area-under-the curve (AUC) statistics were computed for CA125, CA125vel and CA125dt. The results obtained in the group with normal and high (>35 U/ml) CA125 levels were compared.

Results

Forty-four cases of recurrence were diagnosed (7 had CA125 ≤35 U/ml), whereas 15 showed no disease. All of them were correctly catalogued by PET/CT. In ROC analysis, the discriminatory power of CA125 was relatively high (AUC 0.835) and the optimal cut-off point to reflect active disease was 23.9 U/ml. The ROC analyses for the CA125vel and CA125dt showed an AUC of 0.849 and 0.728, respectively, with an optimal cut-off point of 1.96 U/ml/month and 0.76 months, respectively. In patients with normal CA125 and recurrence of ovarian cancer, the CA125vel was significantly higher than in patients without recurrence (p = 0.029).

Conclusion

[¹⁸F]FDG-PET/CT is more accurate than CA125 parameters in the detection of ovarian cancer recurrence. CA125 serum levels are essential; nevertheless, CA125 kinetic values must be considered to detect relapse. Particularly in patients with CA125 within normal values, in which a higher CA125vel is indicative of recurrence.

Resumen

Fundamento y objetivo

Valorar en la recidiva del cáncer de ovario la utilidad del CA125 y sus parámetros cinéticos, velocidad (CA125vel) y tiempo de duplicación (CA125td), y de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) con fluorodesoxiglucosa ([¹⁸F]FDG). Determinar el valour óptimo del CA125, CA125vel y CA125td para detectar recidiva con [¹⁸F]FDG-PET/TC.

Material y métodos

Análisis retrospectivo de 59 estudios [¹⁸F]FDG-PET/TC en 48 pacientes con sospecha de recidiva de cáncer de ovario platino-sensible. Realizamos un análisis ROC (Receiver operating characteristic) y el área bajo la curva (AUC) para el CA125, CA125vel, CA125td. Comparamos los resultados entre los grupos con CA125 dentro de la normalidad y CA125 patológico (>35 U/ml).

Resultados

Fueron diagnosticados de recidiva 44 casos (7 con CA125 ≤35 U/ml), mientras que 15 no mostraron recurrencia. Todos ellos fueron correctamente catalogados mediante la PET/TC. La curva ROC demostró una capacidad discriminatoria del CA125 relativamente alta (AUC 0.835), con un valour óptimo de referencia de 23.9 U/ml. El análisis ROC para la CA125vel y el CA125td mostró un AUC de 0.849 y 0.728, con un valour de referencia de 1.96 U/ml/mes y 0.76 meses, respectivamente. En las pacientes con CA125 en límites normales la CA125vel fue significativamente mayor en las pacientes con recidiva que en aquellas sin enfermedad (p = 0.029).

Conclusión

La [¹⁸F]FDG-PET/TC es más exacta que los parámetros de CA125 en la detección de recurrencia de cáncer de ovario. Los niveles séricos de CA125 resultan esenciales, no obstante, los parámetros cinéticos deben ser tenidos en cuenta en la detección de la recidiva.