Exercise capacity in long-term survivors of pediatric cancer

Abstract

10026 Background: Childhood cancer survivors may have premature symptomatic cardiovascular and noncardiovascular diseases that contribute to reduced capacity for physical activity. Controlled assessments of exercise capacity and identification of risk factors for reduced capacity in survivors are lacking. Methods: We assessed maximal myocardial oxygen consumption (VO2max; measure of exercise capacity) in survivors at least 4 years after diagnosis and sibling controls. We evaluated associations between VO2max and age, sex, treatments, cardiac structure and function, biomarkers, endocrine function, and physical activity. Results: Of 72 survivors (mean age, 22 y; range, 8.0 to 40 y) and 32 siblings (mean age, 20.2 y; range, 8 to 46 y), about half were male. The mean time since cancer diagnosis was 13.4 y (range, 4.5 to 31.6 y). In age- and sibling-pair adjusted analyses, VO2max was lower in survivors than siblings (males, 28.53 vs. 30.90 mL/kg/min, P = 0.08; females, 19.81 vs. 23.40 mL/kg/min, P = 0.03). In male survivors, older age (P = 0.01), higher percent body fat (P < 0.001) and high or low left ventricular (LV) mass Z-scores (P = 0.03) predicted lower VO2max. In females, older age (P < 0.001), methotrexate exposure (P = 0.01), and higher, but normal, LV load-dependent contractility (P = 0.02) predicted lower VO2max. Conclusions: Physical fitness for most participants in each group was poor, and was generally lower in survivors, particularly females. Older age, higher body fat, methotrexate exposure, and extremes of LV mass/function were associated with lower VO2max in survivors. Because physical activity can improve nutritional and cardiac conditions, survivors should be encouraged to engage in regular exercise with close medical monitoring. No significant financial relationships to disclose.