Abnormalities in serum osteocalcin values in children receiving chemotherapy including ifosfamide

In patients undergoing high-dose ifosfamide treatment tubular nephrotoxicity with hypophosphatemia has been described. Long-lasting hypophosphatemia may be associated with bone disease including rickets. Serum osteocalcin is considered a sensitive marker for reduced osteoblast activity and bone formation. In our study we determined osteocalcin serum levels in 11 children with cancer and chemotherapy, comparing them with fractional reabsorption of phosphate, aminoaciduria and a1-microglobulin excretion. A decrease of serum levels of osteocalcin and serum phosphate during chemotherapy was found. Progressive hyperaminoaciduria, a1-microglobulin loss and a low fractional reabsorption of phosphate were also detected during chemotherapy. All parameters tended to become normal after treatment. We conclude that serum osteocalcin levels may decrease soon after the initiation of chemotherapy, indicating low osteoblast activity, probably as a result of phosphate loss. Patients with decreased osteocalcin levels may therefore be at risk for osteoporosis.