In children, both malnutrition and sarcopenia are associated with prolongation of hospital stay, increased morbidity, mortality, and health-related complications. While the decrease in muscle strength refers to "probable sarcopenia", "sarcopenia" is confirmed by adding the decrease in muscle quantity/quality to this situation. In case all three criteria are together, "severe sarcopenia" is mentioned. The aim of this study is the evaluate whether there is a difference in the risk of sarcopenia and related factors in pediatric oncological children compared to healthy controls matched for body mass index group, physical activity level group, sex, and age.

Our research was planned as cross-sectional and descriptive research. Patients diagnosed with pediatric oncologic cancer will be included. Demographic data, malnutrition, the risk for sarcopenia, physical activity status, smartphone addiction, fatigue, and hospital anxiety and depression will be evaluated with questionnaires.

Muscle strength (manual muscle strength assessment), Muscle quantity (the bilateral calf circumference with a tape measure and by bioelectrical impedance analysis (BIA)), and physical performance (Short Physical Performance Battery) will be evaluated by the physiotherapist.

The data of the research will be evaluated with the SPSS package program. After examining the conformity of the data that can be measured in statistical evaluations to a normal distribution with a single sample Kolmogorov Smirnov test, one-way analysis of variance will be applied for comparisons between groups for those with normal distribution, and t-test for independent groups. Kruskal Wallis analysis of variance and Mann Whitney U test will be used in the evaluation of data that do not conform to the normal distribution. Pearson χ2 and Yates corrected Pearson χ2 test Fisher's exact χ2 will be used for qualitative data. As descriptive statistics, numbers and percentages will be given for categorical data, and Median (Min-Max) values and arithmetic mean±standard deviation will be given for quantitative data. For all statistics, the limit of significance will be chosen as bidirectional p<0.05.

As incidence and survival, rates increase in childhood and adolescent cancers, the importance of rehabilitation in this area increases (1-5). Functional limitations in the physical and cognitive domains are reported by children throughout the continuum of cancer care. These limitations are also experienced in very young children under 4 years of age with leukemia and lymphoma, adolescents and young adults struggling with leukemia, sarcoma, or central nervous system tumors (3, 6). Studies in adults who have won the childhood malignancy struggle report adulthood problems. Among these problems, deterioration of physical function, decrease in physical fitness, deterioration of neurocognition, fatigue, and pain, which affect their employment, participation in the life, and quality of life, are reported (2, 5, 7, 8). The roles of rehabilitation professionals, physical medicine and rehabilitation specialists, and physiotherapists in the childhood cancer population are particularly emphasized in the literature to prevent these limitations (1).

Malnutrition in children with chronic diseases is a common condition that causes problems in patient care. Sarcopenia or decreased musculoskeletal muscle mass contributes to the alteration of muscle function. This has been demonstrated in adults with chronic disease, but its impact on clinical outcomes in children has not been adequately described in the pediatric literature. Research in this area is affected by the lack of a uniform definition of sarcopenia in children. However, there is concern that childhood sarcopenia may have a long-term negative impact on growth, neurocognitive development, and quality of life-extending into adulthood. The similarities between sarcopenia and malnutrition are depleted lean muscle mass, changes in muscle function, and suboptimal food intake leading to nutritional deficiencies. In pediatric patients, this leads to growth failure and a potential neurodevelopmental delay in cognition, gross and fine motor development.

In children, both malnutrition and sarcopenia are associated with prolongation of hospital stay, increased morbidity, mortality, and health-related complications (3).

In adult oncological patients (over 18 years of age), the risk of sarcopenia, which is stated to predict malnutrition, is reported to be 40% (9).

As the investigators mentioned before, there is no single definition of sarcopenia with strict rules in childhood sarcopenia. However, in the 2019 European update, three criteria are emphasized in the diagnosis of sarcopenia for elderly individuals. These criteria are:

• decrease in muscle strength,
• decrease in muscle quantity or quality, and
• is stated as a decrease in physical performance. While the decrease in muscle strength refers to "probable sarcopenia", "sarcopenia" is confirmed by adding the decrease in muscle quantity/quality to this situation. In case all three criteria are together, "severe sarcopenia" is mentioned. The same update raises "red flags" in screening for sarcopenia. These red flags include: general weakness, visual loss of muscle mass, decreased muscle strength of the arms or legs, slow walking speed, fatigue, falls, loss of weight, loss of energy, and difficulty performing activities of daily living (10). Therefore, current research aims to question these criteria and the existence of red flags in the pediatric population.

Whether a sedentary lifestyle or physical inactivity due to the disease contributes to the development of sarcopenia (11).

Smartphone addiction is suggested as one of the causes of physical inactivity. Therefore, our study, it is aimed to evaluate both situations.

Physical fitness is the ability to correctly and successfully perform occupational, recreational, and daily activities without fatigue.

It includes two main components: health-related physical fitness (body composition, cardiorespiratory endurance, muscle strength and endurance, flexibility) and performance-related physical fitness (balance, coordination, reaction time, agility, speed, and power). In the current study, pediatric oncology will be evaluated in both patient and control participants.

In future directions for body composition assessments in pediatric oncological cases, "determining the prevalence and clinical significance of sarcopenia and sarcopenic obesity, which are potentially modifiable risk factors, will improve current understanding of the patient's nutritional status, assist in the early identification of those at greatest risk for adverse outcomes, and assist clinicians in their treatment plans. It will enable them to optimize and improve their effects" (12). Further research in this area could lead to improving and customizing chemotherapy dose, optimizing the timing of nutritional and physiotherapy supportive care interventions, and increasing tolerance to both traditional and new treatments. Therefore, progress in this area may have a long-term impact on the patient's quality of life and successful transition to survival (13).

Purpose of the research:

It aims to answer the question of whether there is a difference in the risk of sarcopenia and related factors in pediatric oncological children compared to healthy controls matched for body mass index group, physical activity level group, sex, and age.

Benefits and contributions of the research to science and society:

In the light of the information obtained as a result of the research, a window of opportunity will be provided for the rehabilitation service for the prevention of possible complications that may develop based on the sarcopenia status and related factors in pediatric oncological children, and it is anticipated that this will benefit science and the society.

Current research was planned as cross-sectional and descriptive research. Patients diagnosed with pediatric oncologic cancer will be included. Demographic data, malnutrition, the risk for sarcopenia, physical activity status, smartphone addiction, fatigue, and hospital anxiety and depression will be evaluated with questionnaires.

Muscle strength (manual muscle strength assessment), Muscle quantity (the bilateral calf circumference with a tape measure and by bioelectrical impedance analysis (BIA)), and physical performance (Short Physical Performance Battery) will be evaluated by the physiotherapist.

The data of the research will be evaluated with the SPSS package program. After examining the conformity of the data that can be measured in statistical evaluations to a normal distribution with a single sample Kolmogorov Smirnov test, one-way analysis of variance will be applied for comparisons between groups for those with normal distribution, and t-test for independent groups. Kruskal Wallis analysis of variance and Mann Whitney U test will be used in the evaluation of data that do not conform to the normal distribution. Pearson χ2 and Yates corrected Pearson χ2 test Fisher's exact χ2 will be used for qualitative data. As descriptive statistics, numbers and percentages will be given for categorical data, and Median (Min-Max) values and arithmetic mean±standard deviation will be given for quantitative data. For all statistics, the limit of significance will be chosen as bidirectional p<0.05.

When the literature on the subject of our study was examined, in the study of Lurz et al., computed tomography images of children aged 0-18 were compared by reviewing healthy pediatric trauma victims. In this retrospective study, 23 patients and 46 healthy controls were included. Considering this study and since it was calculated that 26 patients from each group should be included in the power analysis, in our study where muscle strength, muscle quantity/quality, and physical performance parameters will be compared, 30 patients between the ages of 2-18 with and without the pediatric oncological disease (probable case It is planned to include the child (taking into account the losses of the child).

Inclusion Criteria:

• Be between the ages of 2-18 years
• Being under pediatric oncology outpatient/clinical follow-up
• Being able to stand unaided without using a cane/walker

Exclusion Criteria:

• Having any of the diagnoses of hypertension, any cardiac arrhythmia-conduction disorders, coronary artery disease, heart failure, diabetes mellitus, hyperlipidemia, cardiovascular diseases, COPD, pulmonary infection, active infection.
• Depression Illness that causes balance problems
• Peripheral vascular disease
• Presence of disease that prevents standing up with support.
• Presence of diseases that may cause muscle mass loss (cerebral palsy, neuromuscular disease, congenital metabolic disorder, brain damage) mental retardation
• Children with a severe emotional disorder, adjustment disorder
• Physical disability to prevent safe and appropriate testing
• Having used anti-flu medicine in the last 1 week
• Failure to obtain consent.

Participants, who meet inclusion and exclusion criteria, with ages between 2 and 18 years will be selected from Trakya University Faculty of Medicine Pediatric Oncology outpatient polyclinic and clinic and Physical Therapy and Rehabilitation polyclinic and clinic.