Observational studies report associations between physical activity and survival in some types of adult cancer. In addition, some exercise-induced molecules such as catecholamines (e.g., adrenaline) are known to change cancer cell signalling, proliferation and have been linked to clinical outcomes such as survival. The aim of this study is to analyse changes in adrenaline concentration with a single high-intensity interval exercise intervention on a cycle ergometer in children and adolescents during treatment for cancer and to examine the feasibility of the study concept.

Exercise is generally recommended as an adjunct therapy for adult cancer patients as it counteracts the adverse effects of cancer and its treatment. According to epidemiological data, exercise is also associated with a reduced risk of tumour developement and an improval of survival in some tumours. However, the underlying mechanisms by which exercise affects tumour cells are poorly understood in adult cancer patients and mostly unknown in children. Recent studies demonstrate anti-cancer effects of exercise-induced adrenaline through natural killer cell mobilisation and Hippo signalling. In addition, several exercise-induced molecules such as catecholamines (e.g., adrenaline) are known to change cancer cell signalling, proliferation and have been linked to clinical outcomes such as survival. The aim of this pilot study is the analysation of exercise-induced changes in adrenaline concentration in childhood cancer patients and to show feasibility of the study concept. Following recruitment within the first and third cycle of chemotherapy and consent for study participation, all recruited patients perform a single high-intensity interval exercise intervention on a cycle ergometer. Intensity of the intervals is examined both subjectively via a scale for rate of perceived exertion and objectively via changes in lactate concentration pre- and post-exercise as well as heart rate monitoring. Blood samples are taken by trained personnel staff and prepared for processing (centrifuged, snap-frozen). Changes in adrenaline concentration are measured with a commercial ELISA kit. For further identification of metabolites that change with exercise, a non-biased mass spectrometry metabolomics analysis will be used.

Inclusion Criteria:

• newly diagnosed pediatric cancer or relapse
• aged 6-18 years
• between the first and third cycle of chemotherapy
• diagnosis and treatment at the Kinderklinik München Schwabing, Department of Paediatrics and Children's Cancer Research Centre, Technical University of Munich
• German language
• informed consent as documented by signature

Exclusion Criteria:

• Any medical contraindication with respect to a high-intensity interval exercise intervention (e.g., cardiovascular complications, comorbidities, bleeding risk, pain, infection, nausea, orthopedic impairment of the lower extremities)
• inability to follow the procedures and understand the intervention and assessment of the study, e.g., due to cognitive impairment, language problems, psychological disorders etc.