Normal Heart, Hidden Risk—The Need for Exercise Interventions in Childhood Cancer Survivors: Results from the minimALL Study

Background: Acute lymphoblastic leukemia (ALL) accounts for 28% of pediatric cancer cases globally. Despite improved survival rates approaching 90%, long-term cytotoxic chemotherapy often results in muscular atrophy and neuromuscular and cardiac toxicity. These effects, coupled with reduced physical activity, lead to diminished cardiopulmonary fitness, with survivors experiencing adverse health outcomes and functional impairments even 25 years posttreatment. We aimed to validate these findings using cardiopulmonary exercise and echocardiographic data in ALL survivors.

Methods: In the minimALL study, we included 16 ALL survivors who had completed treatment and were considered cured (12 male/4 female, body weight 44.75 ± 16.3 kg, 11.82 ± 3.27 years old). Participants underwent a standardized treadmill cardiopulmonary exercise test (CPET) and extensive echocardiographic evaluation, including speckle tracking. A questionnaire assessed sports participation. Fifteen healthy age- and sex-matched children from our database served as the control group for CPET data (11 male/4 female, 41.6 ± 13.52 kg, 12.03 ± 3.37 years old).

Results: Body weight-normalized VO₂ peak was significantly lower in the study group compared with controls, indicating reduced exercise capacity (mean 37.69 vs. 44.80 L/min/kg). However, O₂ pulse, heart rate, peak breathing volume, and RER were comparable between groups. Echocardiographic assessments showed no differences between ALL survivors and healthy controls, with normal monoplane LVEF (62 ± 6%) and left ventricular strain (−19.35 ± 2%). Survivors reported engaging in 5.0 ± 2.9 hours of extracurricular physical activity per week, with no significant differences in perceived exercise limitations compared with controls (4.9 ± 4.1 hours).

Conclusion: Despite normal echocardiographic results and subjectively normal exercise capacity, VO₂ peak was significantly reduced in the ALL group, the only diminished parameter compared with controls. This reduction likely reflects the prolonged “detraining” during hospitalization rather than cardiac toxicity, as echocardiographic function was normal. These findings underscore the need for early and regular intervention programs to improve cardiopulmonary fitness in ALL survivors. Future research should focus on developing targeted training programs to enhance long-term cardiovascular health, particularly during treatment.

Publication History

Article published online:
11 February 2025