The utility of Tc-99m-DMSA and Tc-99m-EC scintigraphy for early diagnosis of ifosfamide induced nephrotoxicity

A serious undesired effect of certain cytostatics is their nephrotoxicity. In this study, we investigated the toxic effects of ifosfamide and cisplati n by clinical and biochemical parameters in relation to Tc-99m-dimercaptosu ccinic acid (Tc-99m-DMSA) and (TcN)-N-99m, N-ethylenedicysteine (EC) renal scintigraphy. The indicators were urinary beta (2)-microglobulin levels, tu bular resorption of phosphate, urinary protein and glucose excretion, glome rular filtration rate, urinary pH and osmolarity. Thirteen paediatric patie nts (seven boys and six girls), aged 2-16 years, were investigated. Five pa tients received only cisplatin, six patients were treated with ifosfamide a nd cisplatin and two with ifosfamide and carboplatin for various malignanci es. All except three patients had normal DMSA uptake (median, 19; range, 16 -29%) prior to chemotherapy. The reduction in DMSA uptake was unilateral du e to tumour invasion in those three patients. Following chemotherapy, DMSA uptake showed reduction in five patients with or without clinical nephrotox icity. The observed pattern was decreased renal uptake and elevated bladder activity. Three patients with decreased DMSA uptake had normal tubular max imum phosphate reabsorpsion, which suggested subclinical injury. Decrease i n DMSA uptake and tubular phosphate reabsorption (-ITR) was detected simult aneously in two patients. No abnormalities were seen on Tc-99m-EC scintigra phy to suggest nephrotoxicity in our investigation. However, Tc-99m-EC clea rly demonstrated a reduction in split renal function in children with tumou r invasion. In summary, we found that ifosfamide induced tubular injury can be detected with Tc-99m-DMSA scintigraphy before chemotherapy associated n ephrotoxicity is observed by laboratory measurements. Our results also impl y that, although a tubular agent, renal scintigraphy performed with Tc-99m- EC is not able to detect subclinical injury or predict the outcome during t reatment. ((C) 2001 Lippincott Williams & Wilkins).