The Calvert formula is routinely applied for the dosing of carboplatin based on glomerular filtration rate (GFR) as accurately measured using the 51-Cr-EDTA clearance. In general practice, an estimated value of creatinine clearance calculated by the Cockcroft-Gault formula is widely used as a substitution of the GFR. It is reported that there is ethnic difference in renal function and that decrease of GFR by aging is less in Japanese than Caucasians. In 2008, the project of the Japan Society of Nephrology developed the following formula for the calculation of GFR fitting to Japanese patients: GFR (ml/min/1.73 m2) = 194 × serum creatinine−1.094 × age−0.287(×0.739, if female).Method
The aim of this study is to evaluate the efficacy of new estimating method of renal function for Japanese patients with lung cancer. Consecutive patients treated with carboplatin containing chemotherapy were examined. Dosage of carboplatin was determined by the Calvert formula with a target AUC of 5 and GFR calculated by the equation described above. Relationships between adverse effects and clinical features were analyzed.Results
A total of 34 patients (22 males/12 females) were included. Fifteen of the patients received carboplatin/gemcitabine, six received carboplatin/paclitaxel, one received carboplatin/docetaxel and seven received carboplatin/pemetrexed. The mean count of neutrophilcyte and platelet at nadir were 1377 ± 1160 and 12.3 ± 6.8 × 104/μl, respectively. One patient experienced severe thrombocytopenia requiring a blood transfusion; however, the hematological toxicities of the others were mild. There were no correlations between hematological toxicity and clinical values including renal function, age, sex and body surface area.Conclusion
The newly developed formula is effective compensating for inter-patient variability including age, sex and renal function in Japanese patients treated with carboplatin. Ethnic differences including renal function should be taken into consideration for personalized dosing.