Outcome of Advanced Ovarian Cancer Patients Who Do Not Undergo Cytoreductive Surgery in the Era of PARP Inhibitors Maintenance Therapy: a Propensity Score-Based Analysis.

OBJECTIVE:Little is known about patients with advanced ovarian cancer (AOC) who do not undergo cytoreductive surgery but receive maintenance therapy with poly (ADP-ribose) polymerase inhibitors (PARPis). We aimed to investigate the efficacy of PARPi maintenance therapy in nonsurgical patients. METHODS:We retrospectively analyzed the clinical records of patients newly diagnosed with stage III/IV ovarian cancer between April 2014 and March 2024 who did not undergo cytoreductive surgery and responded to first-line chemotherapy. The Kaplan-Meier method was used to estimate the survival outcomes. Adjustment for confounding using propensity score matching (PSM) was performed to compare progression-free survival (PFS) and overall survival (OS) between patients who received PARPi maintenance therapy and those who did not. RESULTS:Eighty-six patients (11.5%) out of 751 newly diagnosed AOC patients were eligible; of these patients, 52 (60.5%) had received PARPi maintenance therapy, and 34 (39.5%) had not. The median PFS and OS for the PARPi maintenance group were 9.8 months (95% confidence interval [CI]=7.2-14.8 months) and 29.2 months (95% CI=21.9 months-not available), respectively. After PSM (27 matched pairs), PFS was prolonged in the PARPi maintenance group compared to the no PARPi maintenance group (log-rank test p<0.001; hazard ratio [HR]=0.34; 95% CI=0.18-0.64). Similarly, OS was prolonged in the PARPi maintenance group compared to the no PARPi maintenance group (p=0.019; HR=0.45; 95% CI=0.23-0.89). CONCLUSION:Patients with AOC who are not undergoing cytoreductive surgery may be a crucial population that benefits from PARPi maintenance therapy.