The influence of age on nephrotoxicity following chemotherapy in children.

Nephrotoxicity is an important adverse effect of chemotherapy in children. Renal function after treatment with either ifosfamide or cisplatinum in children aged 5 years or less ('younger children') was compared with that in those over 5 years ('older children'). Eighteen children (six younger, 12 older) given ifosfamide were studied after completion of chemotherapy, and 28 patients (16 younger, 12 older) were evaluated after cisplatinum. Glomerular filtration rate was measured from the plasma clearance of 51chromium-labelled edetic acid. Proximal tubular function was assessed by determination of plasma and urine calcium, phosphate, magnesium and glucose concentration; calculations of their fractional excretions, and of the renal threshold for phosphate; and measurement of urinary excretion of beta 2-microglobulin. Distal tubular function was evaluated by measurement of the early morning urine osmolality. Younger children had more severe proximal tubular toxicity than older children treated with ifosfamide, with significantly lower plasma phosphate concentrations and higher fractional excretions of glucose. However, there was no evidence of any such difference in glomerular or distal tubular damage after ifosfamide, and no difference in any aspect of renal function between younger and older children treated with cisplatinum. Increased proximal tubular toxicity after ifosfamide in younger children may have serious implications for future growth and development.