HE4 and CA125 serum biomarker monitoring in women with epithelial ovarian cancer.

Background: CA125 is the gold standard serum biomarker for monitoring patients with epithelial ovarian cancer (EOC). Human epididymal protein 4 (HE4) is a novel serum biomarker for EOC patients.

Objective: The objective of this trial was to examine the utility of measuring serum HE4 levels for monitoring EOC patients and to compare HE4 performance parameters to serum CA125.

Methods: A retrospective trial using residual longitudinal serum samples drawn during treatment and monitoring from EOC patients. Serum CA125 and HE4 levels were analyzed at each time point, and a velocity of change was calculated and correlated with clinical status. The null hypothesis was that HE4 is inferior to CA125, and this was tested using concordance and two-sided Fisher's exact testing. McNemar's test was used to assess the overall agreement of the two assays with the clinical status.

Results: A total of 129 patients with 272 separate clinical periods and 1739 events (serum samples) were evaluated. Using a 25% change in serum biomarker levels to indicate change in disease status, the accuracy and NPV determined for HE4 versus CA125 were 81.8% versus 82.6% (p = 0.846) and 87.4% versus 89.7% (p = 0.082), respectively. Concordance comparison of HE4 accuracy / CA125 accuracy was 0.990, indicating HE4 was not inferior to CA125 (McNemar's test p-value = 0.522). Performing a velocity of change analysis, the accuracy and NPV determined for HE4 versus CA125 were 78.3% versus 78.6% (p = 0.995) and 74.9% versus 76.3% (p = 0.815), respectively. Concordance comparison of HE4 velocity accuracy / CA125 velocity accuracy was 0.996, again indicating HE4 was not inferior to CA125 (McNemar's test p-value = 0.884). The combination of HE4 and CA125 velocity changes showed a similar accuracy of 81.3% (p = 0.797 compared to HE4 and CA125 alone) and NPV of 81.1% (p≥0.172 compared to HE4 and CA125 alone), and an increased sensitivity of 70.5% (p≤0.070 compared to HE4 and CA125 alone).

Conclusion: HE4 is equivalent to CA125 for monitoring of EOC patients. The combination of CA125 and HE4 velocities is superior to either marker alone.