Pulmonary dysfunction in survivors of childhood hematologic malignancies after allogeneic hematopoietic stem cell transplantation

The number of long-term survivors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is increasing; however, few studies have addressed their long-term pulmonary function. METHODS: The authors examined 660 baseline and follow-up pulmonary function tests in 89 long-term survivors of pediatric hematologic malignancies and allo-HSCT. RESULTS: At least 1 abnormal lung parameter was seen in 40.4% of baseline tests and developed in 64% of post-allo-HSCT tests (median follow-up: 8.9 years). Abnormal baseline values in ratio of forced expiratory volume in 1 second and forced vital capacity (FEV₁/FVC), FEV₁, residual volume (RV), functional residual capacity (FRC), and FVC were associated with abnormal post-allo-HSCT values. The following pulmonary function values declined significantly with time: FEV1/FVC, forced mid-expiratory flow (FEF_25%-75%), total lung capacity (TLC), diffusion capacity corrected for hemoglobin (DLCO _corr), RV, FRC, and RV/TLC. Older age at the time of allo-HSCT was associated with lower FEV₁/FVC, FEF25%-75%, and DLCO_corr and higher RV/TLC. Patients who experienced respiratory events within 1 year post-allo-HSCT had lower FEV₁ and FVC values and higher RV/TLC from their baseline pulmonary function tests. Female patients had reduced FVC, TLC, and RV values but higher FEV₁/FVC. Pulmonary dysfunction was also associated with high-risk hematological malignancies and peripheral blood HSC product. CONCLUSIONS: Abnormal pulmonary functions in allo-HSCT survivors are prevalent, which underscore the need for risk-adapted continual monitoring and improved preventive and management strategies.