Evaluating homologous recombination status and the efficacy/safety of PARP inhibitors in advanced epithelial ovarianl cancer: A single-institute preliminary experience

OBJECTIVE: Evaluating homologous recombination (HR) status is essential for determining the efficacy of PARP inhibitors (PARPi) in advanced epithelial ovarian, tubal, and peritoneal cancers. However, data from Taiwan remains limited. This study reports preliminary findings on HR status evaluation and PARPi treatment outcomes. MATERIALS AND METHODS: We conducted a retrospective analysis of patients diagnosed with advanced epithelial ovarian, tubal, and peritoneal cancer at a single institute between January 2021 and January 2024. HR status was assessed using ACT or Sofiva Genomics under the CareHRD Project in Taiwan. The safety and efficacy of PARPi were evaluated, and Kaplan-Meier and Cox regression analyses identified factors associated with progression-free survival (PFS). RESULTS: Among 128 patients, 30 (23.4%) were BRCAm, 28 (21.9%) were HRd/BRCAwt, 31 (24.2%) were HRp, and 39 (30.5%) had unknown HR/BRCAwt status. A total of 43 patients received PARPi (29 BRCAm, 12 HRd/BRCAwt, 1 HRp, 1 unknown HR/BRCAwt). Full-dose PARPi was initiated in 32 patients (74.4%), with 22 (51.2%) requiring dose adjustments. At a median follow-up of 25.5 months, PARPi maintenance significantly improved PFS, with median PFS not reached versus 12.2 months in non-users (HR 0.332, 95% CI 0.184-0.589). Three-year PFS was 57.2% vs 22.2%. In the HRd-positive subgroup, PARPi use also prolonged PFS (p= 0.006), with multivariate analysis confirming a 74% reduction in progression risk (HR 0.256, 95% CI 0.085-0.771). CONCLUSIONS: The HRd rate in this Taiwanese cohort aligns with existing literature. PARPi significantly improved survival in HRd patients, but adverse events necessitate careful hematological monitoring for treatment sustainability.