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Vol.39 No.1 contents | Japanese/English |
- Original Article -
Evaluation of Predictive Formulas of Carboplatin Clearance to Calculate the Optimal Dosage in Japanese Lung Cancer Patient
Naoko Sakamoto, Kazuhiro Daido, Motohiro Sugihara, Naoko Ishii, Naoko Sakao and Ken-ichi AritaDepartment of Respiratory disease, Hiroshima Red Cross Hospital and Atomic-bomb Survivors Hospital
Carboplatin (CBDCA) is an agent used frequently in the treatment of various malignancies. Its major hematologic toxicity, thrombocytopenia, is largely dependent on the area under the concentration -time curve (AUC), so it is important to estimate prospectively the individual clearance of plasma carboplatin (CL). CBDCA by intravenous drip infusion over 1 h at a dose of 500 mg/m2 was given to 24 untreated patients with non-small cell lung cancer at the Hiroshima Red Cross Hospital between April 1992 and July 1996, and pharmacokinetics examination for plasma carboplatin was made. We retrospectively evaluated Chatelut's formula, Calvert's formula and Jelliffe's formula to determine whether they could be applicable to Japanese patients with lung cancer. Although the measured AUC significantly correlated with the degree of thrombocytopenia, AUC estimated by the formulas (AUCest) showed no significant correlation. Furthermore, the CL calculated back was overestimated. Therefore, we concluded that it may be necessary to establish a predictive equation of CBDCA CL for Japanese patients. Because there are significant correlations between age, Ccr24h, and CBDCA CL, we tried to derive a predictive equation from the data of 23 patients by multiple regression analysis. Estimated CL (ml/min) =0.52× Ccr24h-2.62× age+223.3. The CL calculated from this equation closely correlated with the measured CL (r=0.71, p<0.01), however, there are some bias between them (MPE%=7.61, RMSE%=23.3). This study may be significant as the first trial of prediction of CBDCA CL for Japanese patients, and a larger-scale study would be needed to derive the precise formula of the optimal CBDCA dosage for Japanese patients with lung cancer.
key words: Carboplatin, Calvert's formula, Jelliffe's creatinin clearance, Chatelut's formula, AUC
Received: June 15, 1998
Accepted: January 19, 1999
JJLC 39 (1): 27-33, 1999
