Risk of progressive kidney damage after acute leukemia

In order to evaluate potential long-term renal sequelae of childhood leukemia, we studied 62 consecutive patients successfully treated for acute leukemia in 1971-83. At the time of this follow-up study they had been off therapy for 1-9 years and they were all in complete remission. Relative renal length was measured from X-ray films of intravenous pyelograms. Median relative renal length prior to the start of chemotherapy was +1.0 SD (range -1.5 to +4.0, n = 35), at discontinuation of therapy +0.5 SD (range -1.5 to +2.2, n = 22), and at follow-up -0.3 SD (range -3.9 to +2.6, n = 61). The mean calculated decrease in relative kidney size was 0.1 SD unit per year during the follow-up time. The median glomerular filtration rate was 110 ml/min/1.73 m2 (range 70 to 164). Six of 60 patients had glomerular filtration rates below 85 ml/min/1.73 m2. Three patients had some evidence of tubular dysfunction documented by increased excretion of urinary amino acids and/or beta-2-microglobulin or by reduced concentrating capacity. In spite of these abnormalities, we conclude that in most long-term survivors of childhood leukemia renal size and function are relatively well preserved. However, slightly reduced glomerular filtration rates in some patients indicated renal damage. A longer follow-up time is needed to find out whether the decrease in relative renal length is still continuing.