Skeletal muscle (muscle) is essential for physical health and for metabolic integrity, with sarcopenia (progressive muscle mass loss and weakness), a precursor of aging and chronic disease. Loss of lean mass and muscle quality (force generation per unit of muscle) in the general population are associated with fatigue, weakness, and slowed walking speed, eventually interfering with the ability to maintain physical independence, and impacting participation in social roles and quality of life. Muscle mass and strength impairments are also documented during childhood cancer treatment, which often persist into adult survivorship, and contribute to an aging phenotype in this vulnerable population. Although several treatment exposures appear to confer increased risk for loss of mass and strength that persists after therapy, the pathophysiology responsible for poor muscle quantity and quality is not well understood in the childhood cancer survivor population. This is partly due to limited access to both pediatric and adult survivor muscle tissue samples, and to difficulties surrounding noninvasive investigative approaches for muscle assessment. Because muscle accounts for just under half of the body's mass and is essential for movement, metabolism, and metabolic health, understanding mechanisms of injury responsible for both initial and persistent dysfunction is important and will provide a foundation for intervention. The purpose of this review is to provide an overview of the available evidence describing associations between childhood cancer, its treatment, and muscle outcomes, identifying gaps in current knowledge.

Introduction: This study aimed to assess longitudinal associations between lifestyle and subsequent malignant neoplasms (SMNs) in young adult childhood cancer survivors. Methods: Members of the St. Jude Lifetime Cohort (SJLIFE) aged ≥18 years and surviving ≥5 years after childhood cancer diagnosis were queried and evaluated for physical activity, cardiorespiratory fitness (CRF), muscle strength, body mass index (BMI), smoking, risky drinking, and a combined lifestyle score. Time to first SMN, excluding nonmalignant neoplasms and nonmelanoma skin cancer, was the outcome of longitudinal analysis. Results: Survivors (n = 4072, 47% female, 29% smokers, 37% risky drinkers, 34% obese, and 48% physically inactive) had a mean (SD) time between baseline evaluation and follow-up of 7.0 (3.3) years, an age of 8.7 (5.7) years at diagnosis, and an age of 30 (8.4) years at baseline lifestyle assessment. Neither individual lifestyle factors nor a healthy lifestyle score (RR 0.8, 0.4–1.3, p = 0.36) were associated with the risk of developing an SMN. Conclusions: We did not identify any association between lifestyle factors and the risk of SMN in young adult childhood cancer survivors.

Background: Lifestyle is associated with meningioma risk in the general population.Aims: We assessed longitudinal associations between lifestyle‐associated factors and subsequent meningiomas in childhood cancer survivors.Methods and results: Childhood cancer survivors age ≥18 years in the St. Jude Lifetime Cohort Study were evaluated for body composition, self‐reported physical activity, cardiopulmonary fitness, muscle strength, smoking, and alcohol consumption at baseline. Time to first meningioma analyses were performed, adjusted for sex, age at diagnosis and baseline assessment, treatment decade, and childhood cancer treatment exposures. The study included 4,072 survivors (47% female; [mean (SD)] 9 (6) years at diagnosis; 30 (8.5) years at the start of follow‐up, with 7.0 (3.3) years of follow‐up). 30% of the participants were survivors of acute lymphoblastic leukemia and 29% of the participants had received cranial radiation. During follow‐up, 90 participants developed ≥1 meningioma, of whom 73% were survivors of acute lymphoblastic leukemia, with cranial radiation being the strongest risk factor (relative risk [RR] 29.7, 95% confidence interval [CI] 10.6‐83.2). Muscle strength assessed by knee extension was associated with a lower risk of developing a meningioma in the adjusted analyses (RR 0.5, 95% CI 0.2‐1.0, p = 0.04 for quartiles 3‐4 vs. 1). No other lifestyle‐associated variable was associated with subsequent meningioma.Conclusion: Independent of cranial radiation, muscle strength was associated with a lower risk of developing a subsequent meningioma in childhood cancer survivors.