Malignant ascites in ovarian cancer: New advances and translational opportunities

Malignant ascites is a defining and clinically challenging feature of advanced ovarian cancer, driving peritoneal dissemination, therapeutic resistance, and poor clinical outcomes. Beyond its traditional description as a protein-rich fluid, high-resolution profiling now reveals ascites as an active ecosystem that enforces vascular leakage, creates dynamic interactions among cellular, acellular, and environmental components, fuels cellular reprograms, and builds profound immune suppression. In this review, we first synthesize established knowledge on ascites formation and composition, and then delineate how this milieu reshapes tumor, stromal, and immune compartments, altering their fate and function. We also integrate current diagnostics and map the therapeutic landscape spanning vascular permeability control, effective locoregional chemotherapy, cellular reprogramming, and stress/metabolic interventions, alongside palliative drainage devices. A deeper understanding of the dynamic interactions and regulatory mechanisms within malignant ascites provides a foundation for developing new therapeutic strategies to overcome its clinical challenges and improve outcomes for ovarian cancer patients.