528MO Is re-introduction or continuation of PARP inhibitors after local therapy for oligo-metastatic progression in patients with relapsed ovarian cancer relevant?

Abstract

PARP inhibitors (PARPi) have revolutionized the management of High-grade epithelial ovarian cancer (HGEOC) treatment. However, a significant number of patients relapse or progress under PARPi leading to the introduction of a new line of systemic therapy as chemotherapy. In patient with a limited number of metastatic sites in progression, -referred to as the oligo metastatic progression- a potential indication for local therapy followed by re introduction or continuation of PARPi treatment rather than initiating a new line of chemotherapy could be proposed. However, the impact of local treatment on progression free survival (PFS) in these patients remains unknown. This international multicenter retrospective study evaluated the efficacy of PARPi continuation or reintroduction in patients with HGEOC after local treatment for oligometastatic progression. The main objective was to assess PFS under PARPi after local therapy (PFS post-LT). Secondary objectives included safety and OS. 74 patients were identified in 20 centers between 04/20 and 11/21. 65% of patients were BRCA mutated and 92% had received ≥ 2 lines of prior systemic chemotherapy before the initial introduction of PARPi. Main progression sites were lymph nodes (42%), peritoneum (20%), liver (11%), other visceral (9%) and other (18%). Local therapy included radiotherapy (44%), surgery (43%), both (7%), cryotherapy or radiofrequency (3%) and other (3%). Median PFS post-LT was 11.5 months [95% CI 7.4; 17.2]. After median follow up of 14.8 months, 5 patients (6.8%) discontinued PARPi due to toxicity. The 1-year overall survival rate was 90.7% [95% CI 79.1; 96.0]. With close to one year without progression or introduction new line of systemic therapy, this study reports the feasibility and potential benefit of this original strategy in patients with oligometastatic progression under PARPi.