Pretransplant Minimal Pleural and Peritoneal Effusion Is a Potential Poor Prognostic Indicator in Allogeneic Hematopoietic Stem Cell Transplantation.

Background: Pleural effusion and ascites developing after allogeneic hematopoietic stem cell transplantation (allo-SCT) are generally associated with inferior overall survival (OS); however, the prognostic value of pretransplant effusion on transplant outcomes remained unclear.

Methods: We retrospectively evaluated minimal pleural effusion and ascites detected by computed tomography in 248 consecutive adult patients who underwent their first allo-SCT from January 2007 to December 2022.

Results: Forty-eight patients demonstrated minimal pleural effusion or ascites within 100 days before transplantation (Effusion group) and the other 200 had no effusion (No effusion group). Serum albumin level was significantly lower in the Effusion group than in the No effusion group (median 3.8 vs. 3.4 g/dL, p < 0.001). Performance status (PS) was significantly inferior and refined disease risk index tended to be higher in the Effusion group. The 2-year OS rate after transplantation was significantly worse in the Effusion group (57.1% vs. 36.7%, p < 0.001). The Effusion group had a significantly lower cumulative incidence of neutrophil and platelet engraftment and higher hepatic veno-occlusive disease. Moreover, a tendency toward higher cumulative incidence of relapse and non-relapse mortality was shown in the Effusion group. In multivariate analysis, the Effusion group had a significantly inferior OS with a hazard ratio of 1.848 (95% confidence interval 1.231-2.774), even after adjustment for disease risk, serum albumin level, PS, and Hematopoietic Cell Transplant-Comorbidity Index points.

Conclusion: Reflecting high disease activity and impaired general condition, pretransplant effusion can be a complementary indicator for poor prognosis in allo-SCT.