# Prognostic impact of effusion in multiple body cavities after allogeneic hematopoietic stem cell transplantation

## TL;DR

This study examines how fluid buildup in multiple body cavities after stem cell transplants affects patient survival, finding that more cavities involved are linked to worse outcomes.

## Contribution

The study introduces a novel analysis of cumulative effusion sites as a prognostic indicator in allo-HSCT recipients.

## Key findings

- Patients with effusions in three cavities had a 18.8% 2-year survival rate, significantly lower than those with fewer or no effusions.
- Effusion in multiple cavities was associated with an additive adverse effect on patient outcomes.
- Cumulative incidence of effusions in different cavities was highest in the first 100 days post-transplant.

## Abstract

Fluid retention presenting as effusions in body cavities is sometimes encountered following allogeneic stem cell transplantation (allo-HSCT). It is unclear whether cavity effusions at independent sites may serve as cumulative correlates of fluid overload and whether a higher number of effusion sites are associated with a worse prognosis. Here, we comprehensively reviewed pleural, peritoneal, and pericardial effusions in 178 first allo-HSCT recipients retrospectively. A total of 123 (69.1%) patients developed effusions in any cavity. New pleural, peritoneal, and pericardial effusions were found after allo-HSCT in 106, 88, and 53 patients, at a median of 38.0 (range, 2–2950), 22.5 (range, 2–1324), and 40 (range, 2–945) days, respectively. The cumulative incidence at day 100 was 41.0%, 40.4%, and 20.8%, respectively. Of the 92 patients who presented with effusions by day 100, 28 patients presented with effusion in a single cavity, 39 in two cavities, and 25 in all three cavities. The 2-year overall survival rates of patients with effusions in zero, one, two, and three cavities by day 100 were 86.1%, 60.0%, 59.6%, and 18.8%, respectively, showing an additive adverse association with outcome. Prospective studies to further characterize fluid dynamics following allo-HSCT are warranted.

The online version contains supplementary material available at 10.1007/s12185-025-03949-7.