Compensatory renal response after unilateral partial and whole volume high-dose irradiation of the human kidney

Abstract

Renal function was prospectively analysed in 26 patients treated with radiotherapy for various types of malignancies. In patients with gastric non-Hodgkin's lymphoma stage I–II (gNHL, n = 5), the 99mTc-diethylenetriamine-penta-acetic acid ( 99mTc-DTPA) renal uptake and the relative 99mTc-dimercapto-succinyl acid ( 99mTc-DMSA) accumulation decreased gradually and concomitantly in the high-dose, whole-volume irradiated left kidney (40 Gy/5, 5 weeks), down to 25 ± 10% (mean ± 1 S.E.M.) and 31 ± 11%, respectively, after 6–9 years. The absolute 99mTc-DMSA uptake in the left kidney declined down to 33 ± 12% whereas in the low-dose, whole-volume irradiated right kidney (12–13 Gy/3 weeks) it increased up to 187 ± 11%. When considering renal volume changes with single photon emission computed tomography, the left kidney in the gNHL patients was reduced to 30 ± 13%, with,surprisingly, a contralateral enlargement up to only 119 ± 7% ( P < 0.05). The overall renal function in this group of patients, as assessed by creatinine clearance and by [ 125I]iothalamate/ 131I]hippuran clearance was reduced to 48–68%. In the Hodgkin's disease patients (HD, n = 7) given 40 Gy in 4 weeks to 30–50% of the left kidney, the 99mTc-DTPA filtration and the relative 99mTc-DMSA uptake in the left kidney was reduced to 75 ± 4% and 81 ± 3%, respectively. The absolute 99mTc-DMSA changes were 78 ± 10% and 135 ± 13%, respectively. No significant renal functional alterations were observed in patients with either ovarian carcinoma ( n = 7) or seminoma ( n = 7). These data suggest a significant, compensatory response of the non-irradiated or low-dose irradiated kidney which, however, appears to be incomplete after contralateral, whole-volume, high-dose irradiation. Such compensatory response might be overestimated when considering only relative or absolute changes in radioactivity uptake.