Abstract
RATIONALE: The relationship between treatment-related impairment of pulmonary function in adult survivors of childhood cancer and subsequent physical function has not been studied. OBJECTIVES: In this prospective evaluation of 606 adult survivors of childhood cancer, we sought to determine the risk factors for, as well as the functional impact of, clinically ascertained pulmonary function impairment. METHODS: We measured FEV1, FVC, total lung capacity (TLC), and single-breath diffusing capacity of the lung for carbon monoxide corrected for hemoglobin (DlCOcorr), expressing the results as percent predicted and lower limit of normal (LLN) values, and we also assessed functional exercise capacity (6-minute-walk distance). Lung radiation exposure was expressed as the estimated percentage of lung tissue that received at least 10 Gy (V10). Associations of clinical and treatment factors with pulmonary function measures were assessed using log-binomial regression to calculate relative risks and 95% confidence intervals. MEASUREMENTS AND MAIN RESULTS: The participants' median age at evaluation was 34.2 years, and the median elapsed time from diagnosis was 21.9 years. Among the sample population, 50.7% had an FEV1 percent predicted less than 80%, 47.2% had an FVC percent predicted less than 80%, 31.2% had a TLC percent predicted less than 75%, and 44.6% had DlCOcorr percent predicted less than 75%. Also, 49.0% had FEV1 less than the LLN on the basis of the Global Lung Function Initiative (GLI) criteria, and 45.4% had FVC less than LLN. Obstructive lung defects (FEV1/FVC, <0.7) were found in 0.8%, but none had obstructive lung defects on the basis of the GLI criterion of FEV1/FVC less than the LLN. Restrictive lung defects (TLC, <75%) were found in 31.2% of participants. V10 and elapsed time since diagnosis were associated with abnormal FEV1 and FVC based on the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 criteria, and with abnormal FEV1 using the GLI criterion. Age at diagnosis was an additional risk factor for abnormal FVC based on the GLI criteria. Age at diagnosis and V10 were associated with abnormal TLC. Increased body mass index, V10, and elapsed time since diagnosis were risk factors for abnormal DlCOcorr. Abnormal pulmonary function tests were associated with decreased 6-minute walk distance. CONCLUSIONS: Impaired pulmonary function in adult survivors of childhood cancer is associated with decreased physical function. These patients may benefit from interventions designed to preserve and/or improve pulmonary function.