Exercise and Health Counseling in Pediatric Hematopoietic Stem Cell Transplantation

Thanks to medical advances, survival rates \>5 years in children/adolescents undergoing hematopoietic stem cell transplant (HSCT) exceed 70%. However, these patients are at high risk of suffering sequelae associated with the underlying disease and/or the HSCT itself, which negatively affects their physical capacity. These patients also tend to spend too much time inactive, which further accelerates functional decline in addition to producing fatigue and impairing quality of life. Therefore, new strategies are needed to minimize the morbidity associated with HSCT. In this effect, although physical exercise represents an interesting adjuvant treatment option for HSCT, scientific evidence in this area is still scarce. Implementation of physical exercise intervention in pediatric HSCT units is challenging due to the lack of research on the effectiveness, affordability and accessibility of this type of intervention. Therefore, establishing the effectiveness of physical exercise under controlled conditions is an important step. The investigators therefore aim to assess the impact of a physical exercise and health counseling program, compared to health counseling only (control group), in pediatric patients with cancer undergoing HSCT on physical-functional, behavioral, psycho-cognitive and clinical outcomes, and blood biomarkers. The investigators will also determine to what extent the benefits of this intervention are maintained over time. Additionally, the investigators will determine the feasibility of implementing the proposed intervention in a real clinical situation in 3 different pediatric HSCT units.

Hematopoietic stem cell transplantation (HSCT), which is used to treat high-risk malignancies, as well as some other conditions or even autoimmune processes, consists of several phases: mobilization and subsequent collection of hematopoietic stem cells from the patient (autologous HSCT) or from a donor (allogeneic HSCT); pre-HSCT conditioning; infusion of patient/donor cells; establishment of a new immune and hematopoietic system in the recipient; and prophylaxis/treatment of possible adverse effects. Since the first successful allogeneic transplant was performed in 1968, thanks to the advances experienced in conditioning regimens, as well as in donor-recipient histocompatibility testing, in patient care and in the management of graft versus host disease (GvHD), together with the increase in the number of donors, the expectations of children and adolescents who receive HSCT have improved, achieving long-term survival rates (\>5 years) \>70%. Yet survivors are at high risk of suffering side effects and toxicities derived from the HSCT itself and/or the underlying disease, with subsequent functional decline. In addition, they show a higher risk of rehospitalization than pediatric cancer survivors who did not receive HSCT and tend to develop chronic pathologies (especially cardiometabolic conditions and frailty) at earlier stages of adulthood than the general population.

The investigators therefore aim to assess the impact of a physical exercise and health counseling program, compared to health counseling only (control group), in pediatric patients with cancer undergoing HSCT on the following outcomes assessed at 3 time points \[start of hospitalization for HSCT (i.e., baseline), and 8 weeks and 3 months after hospital discharge, respectively\]: cardiorespiratory fitness (primary outcome) and ventilatory threshold, muscle strength, left ventricle ejection fraction, fractional shortening and global longitudinal strain, total cardiac mass, functional mobility, adiposity (waist to hip ratio), body mass index, dual-energy X-ray absorptiometry (DXA)-determined body composition (lean and fat mass, bone mineral density), accelerometry-determined physical activity levels, ankle dorsiflexion range of motion, health-related quality of life, cancer-related fatigue, and immune subpopulations. We will also determine clinical outcomes during hospitalization (survival, treatment tolerability, toxicities) as well as molecular biomarkers in blood.

Eligibility Criteria:
Inclusion Criteria:

* Age between 4 and 21 years.
* Undergoing hematopoietic stem cell transplantation (HSCT) for cancer diagnosis in complete remission or without remission, in 3 recruiting Hospitals in Madrid
* Undergoing treatment and follow-up in the same hospital.
* Speaking Spanish.
* Providing signed informed consent.

Exclusion Criteria:

* Not being able to participate in the trial according to protocol.
* Comorbidity or acute condition not associated with the diagnosis and that contraindicates the practice of physical exercise, such as severe deficiencies in the locomotor, neurological, cardiovascular and pulmonary systems.
* Serious or chronic medical or psychiatric condition that may increase the risk associated with participation in the trial or that may interfere with the interpretation of the results and, in the opinion of the investigator in discussion with the team, makes having such condition inappropriate for entry to this study; inability to understand the study requirements.
* Not being able to attend hospital visits to perform assessment tests, nor participate in the physical exercise and health counseling program as stipulated in the protocol.

Inability to understand the requirements of the study.