Alteration in Bone Mineral Metabolism in Children with Acute Lymphoblastic Leukemia (ALL): A Review
In recent years there has been a significant increase in event free survival (EFS) and overall survival in children with cancer. As survival rates for childhood cancer have radically improved, late effects associated with the successful but highly intensive chemotherapy and/or radiotherapy have dramatically increased. Many possible late effects of cancer treatment are recognized in pediatric cancer patients as infertility, endocrine deficiency, renal failure, pulmonary and cardiac toxicity, obesity and osteopenia/osteoporosis. Decreased bone mineral density (BMD) and bone metabolism disturbances have been recognized and reported in literature. Osteopenia/osteoporosis skeletal abnormalities, osteonecrosis and pathological fractures are known to occur frequently in childhood acute lymphoblastic leukemia (ALL) at diagnosis, during and after treatment with chemotherapy. Various studies have revealed different metabolic alterations related to ALL. Some suggestions have been made about their relationship with the disease process. Various metabolic abnormalities may be encountered in the newly diagnosed ALL patients. It includes decreased and increased serum levels of calcium and phosphate. Hypercalcemia may result from leukemic infiltrations of bone and release of parathormone like substance from lymphoblast. Elevated serum phosphate can occur as a result of leukemic cell lysis and may induce hypocalcemia. It has been postulated by other authors that leukemic cells may directly infiltrate bone and produce parathroid hormone related peptides, prostaglandin E and osteoblast inhibiting factors. Hypomagnesemia, hypocalcaemia and hypothyroidisum have been demonstrated in patients with ALL. Some patients may have poor nutrition and decreased physical activities during treatment. However postulations have also been made that chemotherapy may play a role in creating metabolic alterations in children with ALL. Corticosteroid, methotraxate and cranial irradiations have all been assumed as a cause of loss of bone mass. Continuing chemotherapy in children with ALL was assumed with normal growth and normal or high collagen turnover and reduced alkaline phosphatase or impaired osteoblastic activity on mineralization of bone. Considering the derangements in bone mineral metabolism in ALL at diagnosis or with chemotherapy, it is imperative that specific attention and therapeutic measures should be considered.
BSMMU J 2008; 1(1): 29-32