Cisplatin Induced Renal Insufficiency Measured by Glomerular Filtration Rate with 99mTc-DTPA and by using Serum Creatinine based Formulae: A Prospective Study.

INTRODUCTION: Cisplatin also known as Cis-Diammine-Dichloroplatinum (CDDP) is a chemotherapeutic alkylating nephrotoxic agent. Thus, it is necessary to know if renal function is normal before starting chemotherapy. Glomerular Filtration Rate (GFR) can be assessed directly by using a radiopharmaceutical (dGFR). Estimated GFR (eGFR) method use, Serum Creatinine (SCR) levels in mathematical formulae such as Cockroft-Gault (CG) and abbreviated. Modified Diet in Renal Disease (aMDRD). The serum creatinine level is a function of GFR but is relatively insensitive for detecting early renal insufficiency.

AIM: We aimed to correlate the incidence of Renal Insufficiency (RI) before and one month after completion of chemotherapy treatment by various methods.

MATERIALS AND METHODS: In this prospective study, we examined 64 patients with locally advanced head neck and uterine cervix cancers, before and one month after chemotherapy treatment with CDDP. Single agent CDDP was used with dose range between 35mg/m(2) as concurrent weekly chemotherapy.

RESULTS: Baseline RI was seen in 9.3% of patients by SCR levels, in 21.8% by the dGFR method, in 43.75% by the GFR-CG method and in 25% by the GFR-aMDRD formula. We considered GFR of <60 ml/min and SCR >1.5mg% as RI. After completion of treatment, the median RI was seen in 12.5% by SCR levels, 34.38% by dGFR method, 53.13% by GFR-CG method and 40.63% by GFR-aMDRD formula. None of the methods of GFR estimation showed statistically significant increase in RI one month after CDDP infusion. Only a weak correlation was seen between dGFR and eGFR based on SCR value (p=0.006).

CONCLUSION: Baseline RI was detected in 12% more cases when measured by dGFR as compared with SCR level. However, mathematical formulae overestimated baseline RI as compared to dGFR. One month after completion of treatment with CDDP chemotherapy, RI increased in 10%-15% cases as detected by all the four evaluated methods. There is weak correlation between SCR and dGFR thus implicating the importance of dGFR in assessing RI. Thus, despite normal SCR levels, GFR by radioisotope method should also be done as pre-treatment workup for cisplatin based chemotherapy.