Dosing chemotherapy in obese patients: actual versus assigned body surface area (BSA)

Obesity is a chronic disease that has increased dramatically in the past few decades worldwide. More concerning, obesity is linked to many other disease states including cancer and has been shown to increase mortality. Unfortunately, oncology drug development and most clinical trials fail to address the problem of appropriate chemotherapy dosing in obese patients. This can potentially lead to either increased toxicity or decreased efficacy. Although dosing schemas may vary among practices and institutions, many oncologists tend to remain conservative and empirically dose-reduce obese patients despite data suggesting otherwise. The goals of this review were to consider the various aspects of pharmacokinetics in obese patients, to examine the existing literature regarding chemotherapy dosing in obese patients, and to determine the most appropriate weight estimation for body surface area (BSA) dose calculations. Based upon the current clinical data of obesity and chemotherapy dosing it can be concluded there is very limited if any data to support the perception that capping the doses of obese patients is beneficial and more likely this practice may have negative implications on survival outcomes. Under dosing patients with treatable or even curable disease to prevent toxicities could be costing the obese oncology patient population months to years of overall survival.