Patients with epithelial ovarian cancer (EOC) are at high risk of tumor recurrence. Human epididymis protein 4 (HE4) has been shown to be overexpressed in EOC. The primary aim of our study was to evaluate the role of HE4 in predicting recurrence in EOC patients. Furthermore, we assessed the role of HE4 in predicting recurrence after second-line chemotherapy. We retrospectively analyzed data of 92 out of 275 primary EOC patients of the multicenter project "Ovarian Cancer: Diagnosis of a silent killer" (OVCAD). The concentrations of HE4 and CA125 were determined preoperatively and 6 months after the end of platinum-based first-line chemotherapy (FU) using ELISA and Luminex technique, respectively. The role of HE4 and CA125 for prediction of recurrence was determined using receiver operating characteristics (ROC) curves. Out of 92 patients included, 70 (76 %) were responders and 22 (23 %) non-responders in terms of response to platinum-based first-line chemotherapy. Median HE4 concentrations at follow-up (FU) differed between responders and non-responders (60.5 vs. 237.25 pM, p = 0.0001), respectively. The combined use of HE4 and CA125 at FU with cut-off values of 49.5 pM and 25 U/ml for HE4 and CA125, respectively, for predicting recurrence within 12 months after first-line chemotherapy performed better than HE4 or CA125 alone (area under the curve (AUC) 0.928, 95 % confidence intervals (CI) 0.838-1, p < 0.001). HE4 at FU could predict recurrence within 6 months after second-line chemotherapy (AUC 0.719, 95 % CI 0.553-0.885, p = 0.024). The combination of both elevated biomarkers revealed significantly worse estimated median progression-free survival (PFS; hazard ratio (HR) 8.14, 95 % CI 3.75-17.68, p < 0.001) and slightly worse PFS in those in whom only one biomarker was elevated (HR 1.46, 95 % CI 0.72-2.96, p = 0.292) compared to those patients in whom no biomarker was elevated. For the estimated median overall survival (OS), our analysis revealed similar results. HE4 in combination with CA125 performed better than CA125 and HE4 alone in predicting recurrence within 12 months after first-line chemotherapy.
