Cancer treatment in children is generally effective, but unfortunately, it often comes with side effects-unwanted negative impacts. Some medications used in cancer treatment, while beneficial in treating the disease, can have harmful effects on the heart and reduce a child's ability to tolerate physical activities such as climbing stairs, walking fast, running, or exercising. Physical activity is crucial for the proper growth and development of children, as well as for their future health as adults. The heart plays a vital role in pumping blood throughout the body, and its proper function is key to a person's ability to engage in physical activity.

The goal of this study is to understand the factors that influence physical activity levels in children who have undergone cancer treatment with methods that may be harmful to the heart. The researchers aim to investigate how these treatments affect the physical activity levels of these children.

The main questions the study seeks to answer are:

Do children who have undergone cancer treatment involving heart-toxic methods show lower levels of daily physical activity compared to children treated with non-toxic methods?

Is the level of physical activity influenced by heart-toxic treatment, or by other factors such as exercise capacity (measured through physical tests like treadmill or standing bike tests), quality of life, lifestyle, social and demographic factors, body type, or knowledge and motivation related to the positive effects of physical activity?

Participants will:

Complete a questionnaire

Perform an exercise test on a treadmill or standing bike to measure exercise capacity

Take part in the ALPHA physical fitness test, which includes simple exercises like jumping and running

Be measured for height and weight

Undergo a hand-grip test using a hand dynamometer

Wear an activity tracker for 14 days

Have an echocardiogram (ultrasound of the heart)

Researchers will compare 150 children treated with heart-toxic methods for cancer to 150 children treated with non-toxic methods. The children will be between 8 and 18 years old and will be 1 to 5 years post-cancer treatment.

The researchers hope that identifying the factors affecting physical activity levels in children treated with heart-toxic methods may improve cancer therapies for children, reduce side effects, and ultimately lead to increased physical activity. This would help promote better growth and overall health for these children in the future.

Study group Inclusion criteria

1. age 8-18 years,
2. diagnosis of, and completed treatment for, cancer >1 year and <5 years ago,
3. remission of the cancer,
4. treatment involving use of anthracyclines, kinase inhibitors targeting BRC-ABL, hemopoietic stem cell transplantation, and radiotherapy (TBI or mediastinum irradiation),
5. at least 6 weeks since the last signs or symptoms of an infection,
6. written consent signed by the parents/guardians and by patients aged ≥16 years. Control group

a. the same as for the experimental group and, b. cancer treatment without use of anthracyclines, kinase inhibitors targeting BRC-ABL, hemopoietic stem cell transplantation, and radiotherapy (TBI or mediastinum irradiation).

Both groups Exclusion criteria

1. history of another cancer and its treatment with or without the use of anthracyclines, kinase inhibitors targeting BRC-ABL, hemopoietic stem cell transplantation, and radiotherapy (TBI or mediastinum irradiation),

2. significant physical disability or a muscosceletal disorder at the time of the enrollment (congenital or as a consequence of treatment, especially neurological complications and lower extremities conditions and amputation),

3. excessive malaise (at the time of the enrollment),

4. intellectual disability (on the level that disenables the participant from understanding and cooperation during the CPET procedure or ALPHA test),

5. active acute inflammatory disease including the following: autoimmunological, neurological, pulmonological, endocrinological, cardiovascular, and gastrointestinal,

6. platelet count < 20 G/L,

7. hemoglobin concentration < 9g /dL,

8. severe residual changes (protein loss syndrome, peritoneal, pericardial or pleural effusion, arrhythmia, metabolic disorders),

9. previously diagnosed congenital heart defects or other heart diseases (including cardiomyopathy, heart failure, arrythmia),

10. relapse of the cancer at the time of enrollment to the study,

11. severe malnutrition <3 standard deviation (SD) body mass index (BMI) weight for age,

12. chronic concomitant diseases that could affect the CPET outcome, especially endocrinological, neurological, gastrointestinal, and pulmonological*,

13. lack of patient cooperation.

    • endocrinological - decompensated thyroid disease, decompensated diabetes with hypoglycemia; neurological - conditions disabling the CPET performance due to musculoskeletal system alteration, uncontrolled epilepsy, myopathy; gastrointestinal - marasmus, decompensated hepatic insufficiency; pulmonological - asthma, interstitial lung disease, post-infection bronchiolitis obliterans (PIBO) - additionally, pulmonary embolism, lower extremity phlebitis, kidney failure.

The study group will consist of 144 children >1 year and <5 years from a cancer treatment completion involving car-diotoxicity risk factors and are now in the follow-up observation at the outpatient clinic.

The control group is going to involve 144 children who are >1 year and <5 years from a cancer treatment completion without cardiotoxicity risk factors and are now in the follow-up observation.

The sample size was calculated for an unmatched case-control study with the input parameters of a 2-sided confidence level of 0.95, power 80%, ratio of controls to cases 1:1, and odds an ratio of 2.0. The sample size calculation by Fleiss with CC method showed 144 participants for each group. Considering a dropout rate of 10%, the total sample size required is 300.

The raw data (individual participant data (IPD) collected in this study) supporting the conclusions of this article will be made available by the authors, without undue reservation.