# Research Priorities for Malignant Pleural Organization with Loculation and Failed Drainage

## TL;DR

This paper outlines research priorities to better understand and treat malignant pleural effusion that becomes difficult to drain due to fibrosis and loculation.

## Contribution

The paper proposes new research directions, including a rabbit model and molecular profiling, to address treatment challenges in loculated malignant pleural effusion.

## Key findings

- Loculated MPE is increasing due to improved cancer survival and poses challenges for drainage and treatment.
- Profibrogenic factors and mesothelial cell transitions are key areas for understanding and targeting MPE progression.
- Developing a rabbit model and exploring PAI-1 suppression and hyaluronic acid roles could lead to novel therapies.

## Abstract

Malignant pleural effusion (MPE) can lead to pleural organization with loculation and impaired drainage. This condition is becoming increasingly more common due to advancements in cancer therapy and extended patient survival. Factors such as repeated thoracentesis through an indwelling pleural catheter (IPC), intrapleural bleeding, and tumor progression contribute to MPE organization. Loculated MPE causes breathlessness and reduced quality of life, and current therapies, including intrapleural fibrinolytic or enzymatic therapy (IPFT/IET), have limitations in efficacy and safety. Identifying new therapeutic targets is crucial for improving treatment outcomes. Research is needed to understand the role of profibrogenic factors in pleural neoplasia, their regulation, and their impact on different stages of pleural organization. The development of a rabbit model of organizing MPE could provide insights into underlying mechanisms and novel interventions. Comparative studies of pleural tissues and effusions from MPE patients and other forms of pleural organization may reveal valuable information. Cellular and molecular profiling, assessment of biomarkers, and personalized IPFT dosing are potential areas of investigation. Suppression of PAI-1 activity and the role of hyaluronic acid in malignant mesothelioma are also important research directions. Understanding the profibrogenic capacity of pleural mesothelial cells undergoing mesenchymal transition (MesoMT) and identifying key contributors and effectors involved in this process are essential for developing effective treatments for loculated MPE.