Neuromuscular impairments in adult survivors of childhood acute lymphoblastic leukemia: associations with physical performance and chemotherapy doses

After the chemotherapy: potential mechanisms for chemotherapy-induced delayed skeletal muscle dysfunction in survivors of acute lymphoblastic leukaemia in childhood

There is evidence that survivors of childhood cancers, such as acute lymphoblastic leukemia (ALL), have increased rates of long-term skeletal muscle dysfunction. This places them at higher risk of physical restriction and functional impairment as well as potentially contributing to observed increases in cardiovascular disease and insulin resistance in later life. The mechanisms underlying these changes in skeletal muscle are unknown but chemotherapy drugs used in treatment for ALL are strongly implicated. Normal skeletal muscle growth, development, and function are dependent on correctly functioning muscle satellite cells, muscle motor neurons, and muscle mitochondria. Each of these key components is potentially susceptible to damage by chemotherapy in childhood, particularly prolonged courses including repeated administration of combination chemotherapy. If this chemotherapy-induced damage is not fully reversible, impairment of satellite cells, muscle motor innervation, and mitochondria could, either singly or together, lead to the emergence of delayed or persistent skeletal muscle dysfunction many years later. The known effects of individual drugs used in the treatment of ALL are outlined and the need for specific targeted studies to investigate the mechanisms underlying persistent muscle dysfunction in survivors of ALL and other childhood cancers is highlighted.

Back pain among long-term survivors of childhood leukemia

BACKGROUND

The objectives of this study are to determine the prevalence and relative risk (RR) of back pain and identify possible mechanisms of back pain among childhood acute lymphoblastic leukemia (ALL) survivors.

METHODS

Surveys were mailed to 5 + -year survivors of childhood ALL aged 13 to 25 years. Survivors' siblings were also invited to participate in the study. Prevalence of back pain and hip pain among ALL survivors was determined and compared with siblings. Sex, treatment with radiation therapy, obesity, and physical activity were examined for an association with back pain and hip pain.

RESULTS

Forty-four of 99 (44.4%) ALL survivors reported back pain compared with 11 of 52 (21.2%) their siblings (P = 0.007; RR: 2.01; 95% confidence interval = 1.15-3.56). In contrast, 10 of 99 (10.1%) ALL survivors reported experiencing hip pain compared with 1 of 52 (2.0%) siblings experiencing hip pain [P = 0.07; RR: 4.95 (0.65 to 37.57)]. Twenty-six of 43 female survivors reported back pain compared with 18 of 56 male survivors who reported back pain (P = 0.005). Obesity, physical activity, and treatment with radiation therapy were not associated with back pain or hip pain.

CONCLUSIONS

This is the first study demonstrating an increased frequency of back pain among survivors of childhood ALL. Future studies are needed to better define the causes of back pain among childhood ALL survivors.

Pediatric acute lymphoblastic leukemia: where are we going and how do we get there?

Improved supportive care, more precise risk stratification, and personalized chemotherapy based on the characteristics of leukemic cells and hosts (eg, pharmacokinetics and pharmacogenetics) have pushed the cure rate of childhood acute lymphoblastic leukemia to near 90%. Further increase in cure rate can be expected from the discovery of additional recurrent molecular lesions, coupled with the development of novel targeted treatment through high-throughput genomics and innovative drug-screening systems. We discuss specific areas of research that promise to further refine current treatment and to improve the cure rate and quality of life of the patients.