Nephrotoxicity of CDDP assessed estimating glomerular filtration rate with ^99mTc-DTPA plasma sample method

Objective: To assess early nephrotoxicity of CDDP (Cis- diamminedichloroplatinum) manifested by a decline in the glomerular filtration rate (GFR) estimated by plasma two sample clearance method (PSC 2) after ^99mTc-DTPA injection. Study Design: Descriptive study. Place and Duration of Study: Department of Nuclear Medicine, Karachi Institute of Radiotherapy and Nuclear Medicine, Karachi, from September 2004 to January 2005. Methodology: The renal function was assessed on 36 patients suffering from different types of cancer and receiving CDDP in doses of ≥50 mg/m² before and after in each of six CDDP cycles. The GFR was determined by PSC 2 method after ^99mTc-DTPA injection). A paired sample t-test was used for comparision of the mean value with significance at p < 0.01. Results: There were (28 males and 8 females; age range being 16-68 years) The average decline in GFR baseline to the end of sixth cycles was 43.86 ml/min/1.73m ² (p=0.000) as estimated by PSC 2 method. There was a significant fall of average 9.36 ml/min/1.73m² (p < 0.01) in GFR as observed in each cycle of CDDP estimated by the PSC 2 method. In the initial four cycles, CDDP produced a major nephrotoxic effect of average 10.27 ml/min/1.73m ² (p < 0.01) fall in GFR. This then gradually declined to a plateau of an average decline in GFR of 7.76 and 7.31 ml/min/1.73m² (p=0.000) after the 5^th and 6^th cycle respectively. Conclusion: CDDP produced an early nephrotoxicity which was manifested by a significant decline in GFR in each cycle. Tc-99m PSC 2 method for GFR estimation should be used periodically for the early detection of nephrotoxicity induced by CDDP.