Physical fitness and clinically assessed disease burden in long-term childhood cancer survivors-The SURfit study.

Background Identifying disease burden among childhood cancer survivors (CCS) can guide tailored care. Physical fitness predicts health and mortality and may help reduce disease burden in CCS. This study aimed to 1) describe the burden of clinically ascertained adverse health outcomes in long-term CCS, and 2) investigate the association between physical fitness and adverse health outcomes.Methods This study used baseline data of the SURfit study, a randomized controlled physical activity trial. The authors included 163 CCS, diagnosed <16 years, ≥16 years at enrollment, and ≥5 years since last cancer diagnosis. Clinically assessed health outcomes were categorized using the Common Terminology Criteria for Adverse Events. Physical fitness was assessed by cardiopulmonary-exercise-test (CPET), hand-grip strength, and the 1-minute sit-to-stand test (STS). Using multivariable Poisson regression models, this study investigated the association between physical fitness and adverse health outcomes.Results Participants (30.5 ± 8.6 years old, time since diagnosis 22.9 ± 9 years) had 1170 adverse health outcomes, with 99% CCS having at least one. Musculoskeletal disorders were most common (130 of 163 [80%]). Higher levels of physical fitness were associated with fewer adverse health outcomes of any grade (CPET: prevalence rate ratio [PRR], 0.71 per watt/kg bodyweight, 95% confidence Interval [CI], 0.63-0.81, p < .001; hand-grip: PRR, 0.60 kg/kg bodyweight; 95% CI, 0.35-1.03, p = .063; STS: PRR, 0.95 per five repetitions; 95% CI, 0.93-0.97, p < .001).Conclusion CCS participating in an exercise intervention trial experienced a high burden of adverse health outcomes. Increased physical fitness was associated with reduced disease burden for all survivors, emphasizing the importance of encouraging fitness improvements, regardless of cancer history.