Radiation induced lung injury in survivors of childhood cancer

Abstract

20017 Background: The purpose of this study was to examine survivors of childhood cancer, treated with whole lung irradiation (WLI), for signs of pulmonary insufficiency and to correlate pulmonary function test (PFT) results to symptoms of pulmonary dysfunction as detected using the St. George’s Respiratory Questionnaire (SGRQ). Methods: A cross-sectional study was conducted on eligible patients (>2 years from WLI and <18 years at time of diagnosis) who are followed in our institution’s cancer survivor program. Participating patients had a history and physical examination and PFTs performed pre and post bronchodilator challenge. Patients (or their guardians) also completed the SGRQ. The SGRQ, validated for patients 17 to 80 years, generates four values that define respiratory dysfunction: a Symptoms score, an Activity Score, an Impact score, and a Total score. Results: Twenty eligible patients were identified, 12 of whom consented to participate in this study (11 Wilms, 1 Ewing sarcoma). The median current age was 18.4 years (7.5 to 43 years; n=6 < 14 yrs), while patients received WLI (1,200 cGy n=10, 1500 cGy n=2) at a median age of 4.4 years of age (1.7 to 8.7 years). The median time from radiation therapy was 12.6 years (4.7 to 34.3 years). All patients denied smoking, 4 had a history of asthma and all had a normal lung exam. Ten patients had PFTs, 5 of whom (4/5 adults and 1/5 children) had a restrictive pattern noted by PFTs. One further patient (7.5 yrs of age) had a total lung volume 70% predicted but a forced vital capacity 86% predicted. In the pediatric patients (<14 years currently) the FEF 25–75 (4/5) and SGaw (5/5) were increased following treatment with bronchodilator. Twelve participants completed the SGRQ, 4 had elevated total scores (22, 32, 37 and 64). 1 patient with echocardiographic evidence of a dilated cardiomyopathy had an elevated total score but normal symptom score. One patient with a recorded acute pneumonitis after WLI, now 18 years later had normal PFTs and normal SGRQ scores. No correlation was seen between PFT results and SGRQ scores. Conclusions: A restrictive lung function pattern is more common at a later age following WLI in childhood. Mid-expiratory flow and airway conductance following bronchodilator were increased in children. The functional significance of these findings requires further study. No significant financial relationships to disclose.