Carboplatin dosing in obese patients

The study aimed to: 1) Describe the carboplatin dosing criteria in obese patients in routine clinical practicein a general university hospital. 2) Evaluate toxicity based on the dosing criterion used. 3) Assess effectiveness in major diagnoses according to the dosing criterion employed.

An observational, retrospective, descriptive study, including all obese patients (BMI ≥ 30 kg/m²) who started carboplatin treatment between 1^st January 2012 and 31^st January 2015. Data on patient characteristics, disease and treatment were collected. As a result variables were collected: carboplatin dosing methods, dosage criteria, alternative dosing approaches, treatment delays, dose reductions, relative dose intensity, adverse reactions and severity (CTCAE v. 4.0) as well as overall survival and progressive free survival for major diagnoses.

1) Carboplatin dosing at the centre used Calvert's formula for calculating AUC and Cockcroft-Gault's formula for estimating glomerular filtration rate. 2) Cockcroft-Gault's formula employed actual body weight and ideal adjusted body weight in similar proportions. 3) The ideal adjusted body weight was more commonly used in patients with higher obesity and diabetes. 4) In the general population, the developmental trend of toxicity during treatment was greater in the group dosed by actual body weight, reaching significant differences in thrombopenia, neutropenia, GOT elevation, hyporexia and myalgias. 5) Major diagnoses in the present study were ovarian cancer and non-small cell lung cancer. The effectiveness in terms of overall survival and progression-free survival, comparing the groups dosed by actual body weight and ideal adjusted body weight within each pathology did not show statistically significant differences.