Lung function in children after cancer treatment

<bold>Background:</bold> Childhood cancer survivors (CCS) are at risk of pulmonary late effects, but little is known about early functional deficits. We studied lung function in CCS participating in a multicenter prospective cohort study in Switzerland. <bold>Methods:</bold> We invited children aged 6-20 years who completed cancer treatment and were in regular pediatric follow-up. We stratified participants into high-risk (thoracic radiotherapy/surgery, chemotherapy with busulfan/bleomycin/nitrosoureas or allogeneic hematopoietic stem cell transplantation) and standard-risk (any other chemo- or immunotherapy). Primary outcomes were forced expiratory volume in first second (FEV1) and forced vital capacity (FVC) from spirometry, transfer factor for carbon monoxide (TLCO) from diffusion capacity of the lung for carbon monoxide (DLCO), and global lung clearance index (LCI) from nitrogen multiple breath washout (N2MBW). We calculated z-scores using the Global Lung Function Initiative references for FEV1, FVC and TLCO, and latest published references for LCI, and compared them between risk groups using one sample t-test. <bold>Results:</bold> Until now, 112 survivors participated (94% response rate) including 21 (19%) at high-risk and 91 (81%) at standard-risk. Median age at study was 14 years [IQR 11-17], median age at cancer diagnosis 4 years [IQR 2-8]. Mean z-scores of FEV1 were -0.14 in standard-risk vs. -0.50 in high-risk participants (p=0.188) and of FVC -0.22 vs. -0.90 (p=0.018). Mean z-scores of TLCO were 0.49 in standard-risk vs. -0.16 in high-risk participants (p=0.029) and of LCI -0.09 vs. -0.42 (p=0.319). <bold>Conclusion:</bold> Preliminary results from this ongoing study suggest subtle lung function deficits in high-risk survivors, but results need to be confirmed.