Development of Obesity following Treatment for Childhood Malignancies.

Background: Obesity, long viewed as a reversible outcome of personal choices, is influenced by a complex interplay of genetic, physiological, socioeconomic, and environmental factors. A special group of children and adolescents are the childhood cancer survivors (CCSs), as obesity and its comorbidities have been recognized as long-term effects following treatment for childhood malignancies and craniopharyngioma. The aim of this literature review was to report the epidemiological data, pathophysiology and risk factors regarding obesity development in CCS and the possible mediators. The possible mechanisms contributing to increased body mass index (BMI) include hypothalamic hyperphagia and hypothalamic-pituitary insufficiency, corticosteroid therapy, constitutional factors including genetic predisposition and variable sensitivity to corticosteroids. The risk factors are divided into two categories: those related to the initial diagnosis and the treatment modalities implicated and independent factors such as sex, age at diagnosis, ethnic origin, socioeconomic status and BMI at diagnosis.

Summary: Higher risk for developing overweight/obesity face the CCS who had increased BMI at diagnosis, were younger than 6 years of age, received cranial radiation therapy even as low as 6 Gys, had tumors and surgery of the hypothalamic-pituitary region, craniopharyngioma and those who were treated with dexamethasone. They also have high likelihood of developing metabolic syndrome.

Key messages: Obesity is one of the most prevalent long-term sequelae of treatment for childhood malignancies. CCSs already face a heightened risk of chronic diseases. Thus, it is crucial to prevent additional avoidable risk factors, such as obesity. All CCS should have height and weight measurements and BMI calculation, as well as being counseled annually on the importance of regular physical activity and heart-healthy diet.