Discussion
In this study, paediatric patients with cancer before allo-HSCT exhibited significantly reduced fitness compared with healthy individuals, aligning with previous research on paediatric patients with cancer without HSCT.32–34 Even before the initiation of chemotherapy, newly diagnosed paediatric patients with various cancer diagnoses demonstrated reduced physical capacity.33 However, most patients in this situation have traversed an extensive oncological therapy journey and are now embarking on a more intensive treatment, possibly further reducing their fitness levels.
Deisenroth et al32 reported significant decreases in strength values across various muscle groups occurred approximately 36 days after primary treatment in children aged 5–18 years with different cancer entities. Their mean difference in leg extension was approximately −59%, even less than for participants in this study (right leg −36% and left leg −50%). Various factors could contribute to reduced strength, such as steroids, vincristine, reduced physical activity and neuropathic effects.35 Shoemaker et al35 noted muscular weakness in paediatric patients with acute lymphoblastic leukaemia (ALL) and NHL, particularly within the initial 2 months of treatment, suggesting this weakness is often reversible. This may explain why participants in this study (mostly not currently receiving steroids and vincristine) demonstrated less loss. Ness et al34 found significantly lower knee extension strength and hand grip strength in paediatric patients with ALL immediately after diagnosis, along with low bone mineral density, increased body mass, proximal muscle weakness, poor overall motor performance and low endurance. They also identified an impact of impaired knee extension strength on HRQoL.34 Notably, patients in this study reported reduced HRQoL and fatigue, common side effects in children and adolescents (6–19 years and 7–18 years) with mixed cancer entities.36 37 Still, we did not see an impact of knee extension strength on HRQoL in our patients. Compared with other studies, the participants of this trial had fatigue scores comparable with those of other patients with cancer (2–18 years) and were a bit below the mean score in HRQoL.38
The positive effect of the number of supervised exercise sessions before HSCT on hand grip strength supports the need for and beneficial effect of supervised exercise sessions during hospitalisation. Importantly, no exercise-related adverse events were observed during or after testing in our study, indicating the safety of our assessments, consistent with the literature.39
To gain a better understanding of how to support these children and adolescents facing cancer, we conducted an analysis of correlations to identify potential indicators for exercise interventions. We observed that as children get older and have a higher BMI, their exercise capacity tends to decrease, especially as shown by a negative correlation in muscular endurance in the legs. Age was also shown as a predictor of muscular endurance in the legs. This suggests the need for increased endurance and exercise capacity training, particularly among the older age group. Interestingly, there is an opposing effect when it comes to hand grip strength. Here, older participants show better results, as shown in regression analyses. That age seems to be an important factor, which aligns with Braam et al’s40 study of 60 children (8–18 years) with different entities. They revealed that children during or shortly after anticancer therapy were most inactive when having a higher fat mass, being fatigued, older and during treatment.
Additionally, we found that the duration of a child’s hospitalisation is linked to the number of supervised exercise sessions in which they participated. This implies that an extended hospitalisation provides more opportunities for supervised exercise sessions. However, it clarifies the association with poorer HRQoL and an increased level of fatigue, too. This highlights the importance of providing additional support and interventions for these patients, given the potential negative impact of extended hospitalisation on their well-being.
Clinical implications
Poor fitness in children before HSCT shows the needo improve their fitness status. Children with lower fitness levels benefit from exercise programmes during HSCT,23 indicating potential for improvements. Additionally, initial data for adult patients undergoing HSCT suggests that exercise may improve survival and that higher baseline fitness levels are associated with lower mortality rates.16 Better pre-HSCT fitness is linked to improved overall survival.17 Therefore, enhancing pre-HSCT fitness status is recommended, potentially contributing to a better outcome for paediatric patients undergoing HSCT.
Our findings further indicate significantly reduced physical performance levels before paediatric HSCT, which carries several clinical implications. First, they underscore the need for developing prehabilitative interventions to stabilise physical well-being and HRQoL before the demanding treatment of HSCT. Enhanced physical fitness in patients may lead to better resilience to treatment and reduced side effects. Second, adolescent patients may benefit from targeted aerobic training, for example, on a stationary bicycle, due to their very low exercise capacity before HSCT. Third, our study suggests that supervised exercise sessions (comprising various child-adapted exercises) before HSCT are associated with better hand grip strength, highlighting the importance and feasibility of improving fitness before allo-HSCT. The design and methods of the exercise sessions were planned and conducted according to guidelines from the Network ActiveOncoKids.40 Additionally, the number of inpatient days before HSCT should be minimised whenever possible, as hospitalisation seems to be associated with higher fatigue levels, which can be minimised through exercises.41 Therefore, implementing prehabilitative strategies to enhance fitness may reduce side effect-related inpatient days and result in better HRQoL and less fatigue. A multidisciplinary team is recommended to optimally support patients, along with additional counselling and coaching for the entire family.
Limitations
One limitation is the small patient sample, potentially hindering broader conclusions or generalisations. Missing data due to medical or psychological reasons is another limitation. The wide age range, while providing diversity, may confound variables affecting result consistency. Additionally, the gender imbalance restricts gender-specific assessments. Nevertheless, the study serves as a valuable validation of existing knowledge and offers practical insights for patient care. It highlights specific age groups, particularly older children, who may benefit from targeted training in certain areas. The study’s findings provide a foundation for developing training recommendations to enhance care for paediatric patients with cancer undergoing HSCT.