Formulas Used:

1. Body Surface Area (BSA in m²) (CALGB method): SQRT(height(cm) x weight(kg) / 3600)
2. Ideal Body Weight (IBW in kg):
   • Standard formula: (2.3kg x (height(in) - 60)) + (45.5kg if female, 50.0kg if male)
   • Lorentz formula (only used if the Chatelut formula is being used to calculate the carboplatin clearance): height(cm) - 100 - ((height(cm) - 150) / (4 if male, 2 if female))
3. Calculated Creatinine Clearance (CrCl, also known as carboplatin clearance if the Chatelut formula is being used):
   • Traditional Cockcroft-Gault formula: ((140 - age(yrs)) x (lesser of IBW(kg) or actual weight(kg))) / (72 x serum creatinine(mg/dl))
     • Multiply by another factor of 0.85 if female
     • Intended for ages 18-110, weight 35-120 kg, serum creatinine 0.6-7 mg/dl
   • Modified Cockcroft-Gault formula: ((140 - age(yrs)) x (actual weight(kg))) / (72 x serum creatinine(mg/dl))
     • Multiply by another factor of 0.85 if female
     • Intended for ages 18-110, serum creatinine 0.6-7 mg/dl
     • NOTE: This is the more popularly used version of the Cockcroft-Gault formula at present. See literature for supporting data (e.g., Hutson P et al. Carboplatin Dosing in Obese Patients. Proc Am Soc Clin Oncol 2000, abstract 725).
     • NOTE: This is the version of the Cockcroft-Gault formula more commonly used in carboplatin-related non-GOG clinical trial protocols these days, but IF THE PATIENT IS BEING TREATED ON A PROTOCOL, YOU SHOULD BE CAREFUL TO READ THE REQUIREMENTS OF THE PROTOCOL ON THIS MATTER.
   • Chatelut formula: (0.134 x weight(kg)) + ((1 if male, 0.686 if female) x 218 x weight(kg) x (1 - (0.00457 x age(yrs))) / (serum creatinine(mg/dl) x 88.4))
     • The 88.4 factor converts the creatinine from the U.S. mg/dl value you entered to the S.I. µmol/L value required by the Chatelut formula.
     • Intended for ages 18-100, weight 40-120 kg (88-264 lb), height 130-220 cm (51-87 in), serum creatinine 53-531 µmol/L (0.6-6.0 mg/dl).
     • Adjustment for obesity: The "weight" used in the Chatelut formula is the actual body weight if the actual body weight to ideal body weight ratio is less than 1.2 Otherwise the "weight" used is the average of the actual body weight and the ideal body weight. Note that the ideal body weight used in the context of the Chatelut formula is the Lorentz formula rather than the standard formula.
   • Sanaka formula: (Actual body weight(kg) x ([19 if male, 13 if female] x plasma albumin level(g/dl) + [32 if male, 29 if female])) / (100 * serum creatinine(mg/dl))
     • Intended to predict creatinine clearance using serum albumin in elderly patients with low muscle mass
     • Results valid for ages 60-92, body weight 24-61 kg (53-134 lb), plasma albumin 1.4-3.9 g/dl, serum creatinine 0.4-5.6 mg/dl
     • Results may be invalid for patients with nephrotic syndrome, severe hepatic disease, malnutrition, acute and chronic inflammation, or other albumin-wasting states.
   • Schwartz formula: [0.45 for ages < 2, 0.55 for ages 2-12 or female ages 13-20, 0.7 for male ages 13-20] x height(cm) / serum creatinine(mg/dl)
     • Also multiply by (BSA(m²) / 1.73m²) if adjusting for BSA
     • Intended for children ages 6 months to 20 years, height 40-200 cm (16-79 in), serum creatinine 25-800 µmol/L (0.3-9.0 mg/dl)
   • Jelliffe formula: (98 - (0.8 x (age(yrs) - 20))) / serum creatinine(mg/dl)
     • Multiply by another factor of 0.90 if female
     • Also multiply by (BSA(m²) / 1.73m²) if adjusting for BSA
     • NOTE: This version of the Jelliffe formula assumes a stable creatinine in an adult, non-obese, non-emaciated patient with normal muscle mass who is not on hemodialysis. This calculation is not applicable to patients less than 18 years old, serum creatinine less than 0.6 mg/dl, weight less than 35 or more than 120 kg, unstable creatinine, muscle mass less than 70% or more than 130% of normal.
     • Note that all carboplatin-related GOG protocols require use of the (non-BSA-adjusted) Jelliffe formula in order to provide comparability with all historical GOG data which has been generated under this rule. This decision was reviewed (and left unchanged) by GOG's Medical Oncology Committee as recently as the Summer 2002 GOG meeting. In fact, GOG not only does not adjust for BSA in carboplatin dosing but also calculates all BSA-based dosing for other agents using an arbitrary constant BSA of 1.73m².
4. Carboplatin Dose:
   • Calvert formula (used with Cockcroft-Gault and Jelliffe formulas for creatinine clearance): Total dose (mg) = target AUC(mg/ml/min) x (CrCl + 25)(ml/min)
   • Chatelut formula (used with Chatelut formula for carboplatin clearance): Total dose (mg) = target AUC(mg/ml/min) x CrCl(ml/min)