Pulmonary function studies in children treated by chemoradiotherapy and stem cell transplantation.

Background: Management of pediatric patients with malignant and hematological diseases is frequently associated with pulmonary complications. We assessed pulmonary function at diagnosis and during a 5-year follow-up to identify risk factors associated with pulmonary deterioration.

Procedure: Ninety patients (age range 3-20) who were treated at the Pediatric Hematology-Oncology Department, Sheba Medical Center, Israel, were entered into the study. Pulmonary function testing was performed at diagnosis and at least twice during the study period.

Results: At diagnosis and thereafter values of spirometry, total lung capacity, functional residual capacity and diffusion capacity were significantly lower than predicted (P < 0.002 for all indices). The ratio between residual volume and total lung capacity (RV/TLC) was significantly higher than normal at diagnosis and throughout the study (P < 0.001). Age and treatment modalities did not show any effect on lung-function during the study. A subgroup of seven patients (8%) developed Bronchiolitis obliterans (BO) after stem cell transplantation and development of graft versus host disease (GVHD). These patients' baseline FEF25-75 values (small airway disease) were significantly lower than FEF25-75 values of controls and other patients while all other parameters were similar. The RV/TLC in the BO patients gradually increased relative to other patients during the 5-year follow-up.

Conclusion: Lung-function in pediatric hemato-oncological patients at diagnosis is lower than predicted. Abnormal baseline FEF25-75 may be a risk factor for the development of BO in the setting of GVHD after treatment. Careful monitoring, especially of FEF25-75 and RV/TLC at baseline and in the first period after diagnosis.