Cardiopulmonary exercise testing in evaluation of the functional capacity of survivors of childhood cancer

Progress in the treatment of pediatric cancer has resulted in a growing population of survivors of malignancy treated in childhood. These individuals may have evidence of multiple organ system impairment related to oncologic disease and its therapy. Metabolic exercise testing measures cardiovascular, pulmonary and musculoskeletal components of maximal exercise performance, quantifying functional capacity. This information has been used to describe the clinical syndromes related to anthracycline exposure, radiation therapy and bone marrow transplantation. Impaired performance at exercise testing has been quantified in general as decreased endurance, increased symptomatology and excess cardiac arrhythmias. Specific evaluation of the cardiovascular system in survivors of childhood cancer demonstrates impaired aerobic capacity and impaired hemodynamic response to exercise, with relatively increased heart rate, decreased stroke volume and decreased maximal cardiac index. These abnormalities correlate with risk factors for cardiovascular impairment: increased anthracycline dose, female sex, younger age at treatment and longer time to follow-up evaluation. Changes in musculoskeletal function impact variably on exercise capacity. Metabolic exercise testing which measures the integrated function of multiple organ systems identifies subclinical abnormalities useful in monitoring functional capacity and guiding intervention.