Jaime E. Poquet Jornet

Variability of carboplatin dose calculation methods in Spain

Objective To describe and analyze the variability in carboplatin dosing strategies in Spanish hospitals. Methods We designed a questionnaire consisting of 19 multiple-choice items structured in two sections (hospital characteristics and carboplatin dosing data). The questionnaire was sent by e-mail to all the oncology pharmacists included in the register of the Spanish Oncology Pharmacy Group (GEDEFO), and we analyzed the completed questionnaires. Results Response rate was 33.5% from a total of 185 pharmacy services invited to take part in the survey. All hospitals used the Calvert formula to calculate carboplatin dose with glomerular filtration rate estimated by a formula, most commonly the Cockcroft-Gault equation (80.7%). Carboplatin doses were capped in most hospitals (91.9%): 54.8% capped creatinine clearance at 125 mL/min, 11.3% capped serum creatinine, and 19.3% capped both creatinine clearance and serum creatinine. Serum creatinine cut-off values ranged from 0.36 mg/dL to 1 mg/dL. The most commonly used body weight was actual body weight for underweight, normal weight, and overweight patients. The use of adjusted ideal body weight increased in obese and especially in morbidly obese patients. Conclusion The results from this survey show the variability that exists in carboplatin dose calculation methods among Spanish hospitals and the need to continue investigating to find the optimum dose calculation method and unify criteria to avoid differences between sites that can affect effectiveness and toxicity of carboplatin-containing treatments.Objective To describe and analyze the variability in carboplatin dosing strategies in Spanish hospitals. Methods We designed a questionnaire consisting of 19 multiple-choice items structured in two sections (hospital characteristics and carboplatin dosing data). The questionnaire was sent by e-mail to all the oncology pharmacists included in the register of the Spanish Oncology Pharmacy Group (GEDEFO), and we analyzed the completed questionnaires. Results Response rate was 33.5% from a total of 185 pharmacy services invited to take part in the survey. All hospitals used the Calvert formula to calculate carboplatin dose with glomerular filtration rate estimated by a formula, most commonly the Cockcroft-Gault equation (80.7%). Carboplatin doses were capped in most hospitals (91.9%): 54.8% capped creatinine clearance at 125 mL/min, 11.3% capped serum creatinine, and 19.3% capped both creatinine clearance and serum creatinine. Serum creatinine cut-off values ranged from 0.36 mg/dL to 1 mg/dL. The most commonly used body weight was actual body weight for underweight, normal weight, and overweight patients. The use of adjusted ideal body weight increased in obese and especially in morbidly obese patients. Conclusion The results from this survey show the variability that exists in carboplatin dose calculation methods among Spanish hospitals and the need to continue investigating to find the optimum dose calculation method and unify criteria to avoid differences between sites that can affect effectiveness and toxicity of carboplatin-containing treatments.

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.