Francisco Javier Carrera Hueso

Toxicity and effectiveness of carboplatin in obese or overweight patients

Introduction. Carboplatin dose calculation is based on the Calvert formula, which includes body weight of patient as a variable. Different authors have evaluated the influence of body weight used in this formula (adjusted, ideal or actual) in obese or overweight patients. Our objective is to evaluate the efficiency and toxicity of carboplatin, dosed for a target AUC 5-6 using the Calvert formula with the actual body in obese or overweight patients with ovarian cancer. Method. This is a retrospective cohort study of patients with ovarian cancer who started treatment with carboplatin dosed to an AUC 5-6, between 2012 and 2013. The patients included were classified into two groups according to Body Mass Index (BMI) (obese/overweight; BMI >25 kg/m2 or normal-weight, BMI ≤25 kg/m2). The efficiency was measured by Progression-Free Survival (PFS),Time To Progression (TTP) and Overall Survival (OS). Toxicity was measured by dose reductions and delays of treatment cycles. Results. 19 patients were included in the study: 13 in the normal-weight group and six in the obese/overweight. Each patient received between three and seven cycles of chemotherapy, representing a total of 113 cycles. None of the patients died during the study so the OS is 100% and the TTP is equal to PFS. There is no statistically significant difference in PFS between the two groups (p = 0.899). There is also no statistically significant difference between the number of cycles that required dose reduction between the groups (p = 0.305) and the number of cycles that required to be delayed (p = 0.165). Discussion. The study found no statistically significant difference in terms of efficiency and toxicity in patients with ovarian cancer obese or overweight compared to normal-weight to calculate the dose of carboplatin AUC 5-6 for a target and using the current weight on the Calvert formula. These results show that, initially, it is appropriate to use the actual body weight. However, due to the limitation of the small number of patients included, the study should be extended in time or studied more types of tumoursObjective To evaluate the efficiency and toxicity of carboplatin using actual body weight in obese/overweight patients using the Calvert formula with Cockcroft-Gault for CrCl estimation. Methods We evaluated the association of BMI in regards to efficiency and toxicity in a retrospective cohort study of patients who started treatment with carboplatin between 2012 and 2013. Cohorts included obese/overweight patients and normal-weight patients. Efficiency was measured by overall survival, progression-free survival and response rate. Toxicity was measured by the proportion of dose reductions and delays of chemotherapy cycles. We utilized a bivariate and multivariate analysis. Results Eighty-six patients were included in the study (50% obese/overweight). There was not a statistically significant difference in effectiveness and toxicity between the two groups in BMI. In the multivariate analysis, BMI not was associated with overall survival (hazard ratio: 0.95, 95% CI: 0.54-1.66, p = 0.849), progression-free survival (hazard ratio: 0.91; 95% CI: 0.54-1.54; p = 0.732), cycle delays (odds ratio (OR): 1.47, 95% CI: 0.80-2.69, p = 0.218) or carboplatin dose reductions (OR: 0.87, 95% CI: 0.35-2.15, p = 0.760). Response rate was 53.5% in both groups. Conclusions In our study, obese and overweight cancer patients did not show a statistically significant difference in terms of effectiveness and toxicity compared to normal-weight cancer patients who were treated with carboplatin using their actual body weight with the Calvert formula and Cockcroft-Gault for CrCl estimation. Therefore, it was appropriate to use the actual body weight for our patients.