Dosing of chemotherapy in obese and cachectic patients: results of a national survey

Background It is not unusual to find obese and cachectic patients in the hematology oncology setting. However, information on dosage in these groups is scarce. Objective The objectives of our study were to explore the dosing strategies applied in the treatment of obese and cachectic cancer patients and to determine whether these strategies are applied in clinical trials. Setting Members of the Spanish Group for the Development of Hematology–Oncology Pharmacy (GEDEFO). Methods We invited all cancer hospital pharmacists to participate in a survey. Main outcome measure Descriptive statistics of the dosing strategies approaches. Results We invited 159 eligible hospitals to participate, and 38 responded to the survey. A total of 50 surveys were received: different strategies were applied by different physicians from the same hospital and by hematology and oncology departments. Body mass index was used to define obesity and cachexia in 40 and 30 % of the cases, respectively. Capping the body surface area (BSA) was the approach most commonly followed (64.1 %) in obese patients, whereas no specific approach was adopted in cachectic patients. In hematology patients, the BSA calculation was based on ideal body weight or adjusted body weight in 16.0 % of cases (n = 2) and 50.0 % of cases (n = 6), respectively; in oncology patients, use of adjusted or ideal body weight was negligible. Actual body weight was the main approach in obese patients (35 surveys) and cachectic patients (48 surveys). Creatinine clearance was assessed mainly using the Cockcroft and Gault equation (around 76.0 % of responses). As for clinical trials, 64.1 % of the respondents (n = 25 hospitals) considered the criteria from each clinical trial individually. Conclusions Dose adjustments are more frequent in obese patients than in cachectic patients. In cancer oncology patients, dose is adjusted mainly by hematology and hematopoietic cell transplant teams. Capping BSA is the most frequent strategy, followed by calculating actual body weight.