Real-world outcomes of PARP inhibitor maintenance in advanced ovarian cancer: a focus on disease patterns and treatment modalities at recurrence

Background: The utilization of poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) as a first-line maintenance therapy for advanced ovarian cancer has increased significantly, with ∼80% of patients potentially eligible. This expansion has led to a rise in the population experiencing platinum-sensitive recurrence, yet data on first recurrence during PARPi are limited. This real-world study from a high-volume referral center aims to elucidate recurrence rates, disease distribution, and treatment modalities at the time of progression in PARPi-treated patients. Materials and methods: We analyzed our prospectively maintained database to identify patients receiving first-line PARPi maintenance from January 2019 to December 2022 at our institution. Results: A total of 373 cases were identified, 51.5% of which had a BRCA mutation. With a median follow-up of 38 months, 44.8% of patients experienced recurrence, with 90.3% having a platinum-free interval exceeding 6 months. Recurrences were oligometastatic in 44.9% of cases, with BRCA mutations strongly predicting this pattern (hazard ratio 3.014, confidence interval 1.486-6.113, P = 0.002). The median progression-free survival was 39 months, significantly longer for BRCA-mutated and homologous recombination deficiency-positive patients. Over one-third of platinum-sensitive recurrent patients were candidates for local treatments, and PARPi administration was prolonged in 53.7%. Conclusions: Despite the notable survival improvement, a significant proportion of the population will experience a platinum-sensitive recurrence on PARPi, for which local treatments are often a viable option. Our study highlights the need for further research to determine whether the ablation of oligometastatic sites has a significant impact on post-recurrence survival and to identify if there are patient categories that would benefit from personalized follow-up due to their susceptibility to oligometastatic recurrences and local treatments.