Reduced cardiopulmonary fitness in childhood acute lymphoblastic leukemia survivors

Abstract

PURPOSE/OBJECTIVE: One in 600 adult individuals in USA is a survivor of childhood cancers. A number of chemotherapeutic agents are associated with long-term cardiopulmonary toxicities. Low cardiopulmonary fitness is a strong predictor of all-cause mortality, cardiovascular disease and functional limitations. The purpose of this study was to evaluate cardiopulmonary fitness in Chinese paediatric acute lymphoblastic leukemia (ALL) survivors and to identify high risk group for early behavioral modification. MATERIALS AND METHODS: Childhood ALL survivors were recruited. Cardiopulmonary fitness expressed as peak oxygen consumption (peak VO2) was measured. Exercise response of ALL survivors was compared to a group of age, gender and BMI matched healthy controls. Maximal effort was defined as a respiratory exchange ratio (RER) > 1.10 with clear signs of exhaustion RESULTS: Fifty-one survivors (27 males, 24 females) with a mean age of 18.3 +/- 4.5 years were included in the analysis. Peak VO2 was significantly reduced in survivors compared with controls (35.2 +/- 9.8 vs 39.9 +/- 11.9 mL x Kg -1 x min -1 respectively, p < 0.05). Survivors also had significantly lower peak heart rate (HR) (186 +/- 9 vs 192 +/- 11 bpm, p < 0.05) and greater heart rate reserve (HRR) (5.3 +/- 9.8 vs -0.9 +/- 11.5 bpm, p < 0.05) than controls. Sixty-seven percent of survivors (15 males, 19 females) failed to achieve a peak HR greater than 95% of predicted maximal HR, compared to 41% in the control group (p < 0.05). The mean duration from assessment and termination of treatment for survivors with suboptimal peak HR (n = 34) vs those who could achieved optimal peak HR (n = 17) was 8.9 +/- 3.5 and 12.2 +/- 4.7 years respectively (p < 0.05). ALL risk stratifications in these 2 groups were similar. CONCLUSIONS: Significant proportion of ALL long-term survivors had reduced cardiopulmonary fitness which was a negative risk factor or subsequent cardiovascular risk. Early behavioral modifications are probably justified in this group of patients.