Serum CA125 level as predictors of the efficacy of olaparib maintenance therapy for platinum-sensitive relapsed ovarian cancer.

ABSTRACT

AIM: Ovarian cancer is a gynecological malignancy with a poor prognosis. For platinum-sensitive relapsed ovarian cancer, maintenance therapy with poly-ADP ribose polymerase (PARP) inhibitors after chemotherapy is considered; however, olaparib treatment does not always lead to sufficient progression-free survival (PFS). This study aimed to identify factors that predict the efficacy of maintenance therapy using olaparib in platinum-sensitive relapsed ovarian cancer. METHODS: Twenty-seven patients with platinum-sensitive relapsed ovarian cancer, who received initial treatment and showed complete or partial response to prior chemotherapy at our hospital, were included. The primary outcome was the time from the end of previous platinum-based chemotherapy to disease progression (PFS). The Kaplan-Meier method was used to generate time-to-event curves for PFS; multivariate analysis was performed using the Cox proportional hazards regression model. RESULTS: The median PFS was 12 months (95% confidence interval [CI] 8.3-15.8). Before olaparib administration, the median PFS was 12 months in the <4.1 neutrophil-to-lymphocyte ratio group and 4 months in the ≥4.1 group, with PFS being significantly better in the <4.1 group (log-rank p = 0.023). When comparing serum cancer antigen 125 (CA125) levels, the median PFS was 13 months in the <18 U/mL group and 6 months in the >18 U/mL group (log-rank p = 0.022). Multivariate Cox regression analysis revealed that CA125 was the factor affecting PFS (hazard ratio 4.85; 95% CI 1.53-15.38). CONCLUSIONS: Serum CA125 levels at olaparib initiation in patients with platinum-sensitive relapsed ovarian cancer may predict PFS as an effect of maintenance therapy using olaparib to treat recurrent disease.