Introduction: In patients with newly diagnosed advanced high-grade serous and endometrioid epithelial ovarian cancer (EOC) first-line maintenance therapy with poly(ADP-ribose) polymerase inhibitors (PARPi) tremendously improved progression-free survival (PFS). Yet, data on the effect of PARPi in proportion to postoperative residual disease status were lacking.
Material and methods: A systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items of Systematic reviews and Meta-Analysis (PRISMA) guidelines. We searched Medline/Pubmed, Embase and Cochrane databases as well as meeting abstracts until 18th March 2023. Hazard ratios (HRs) alongside their 95% confidence intervals (CIs) for PFS were extracted from the studies. A subgroup analysis was conducted to examine the effect of PARPi according to postoperative residual disease.
Results: A total of six phase III randomised controlled trials were included and comprised SOLO 1, PAOLA 1, PRIMA, PRIME, ATHENA-MONO and VELIA. Patients who received PARPi following complete gross resection showed greatest PFS benefit. Compared with placebo, maintenance with PARPi significantly improved PFS in patients with macroscopic residual disease (pooled HR 0.55; 95% CI 0.44-0.68). This magnitude was comparable to that found in patients with complete gross resection (pooled HR 0.53; 95% CI 0.41-0.67).
Conclusions: Patients with macroscopic residual disease benefit from PARPi at the same extent as cases with complete gross resection. However, patients with complete gross resection who were treated with PARPi show the most favourable PFS rates. Hence, the pursuit of achieving complete cytoreduction remains valid in the PARPi era.
Keywords: Cytoreductive surgery; Epithelial ovarian cancer; PARP inhibitors; Postoperative residual disease; Progression-free survival.
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