Variation in the practice of dose reduction of chemotherapeutic agents after weight loss or amputation.

Abstract

Dose reduction of chemotherapeutic agents in response to weight loss or amputation is important in avoiding excessive therapy-related toxicity. Several methods of calculating this dose reduction are currently in use, including dose reduction in proportion to (a) the reduction in body surface area (BSA), (b) the amount of weight lost, and (c) no dose reduction unless toxicity is observed. Each of these methods results in the administration of a different dose, and few guidelines exist as to the preferred method. We conducted a survey of a large group of pediatric oncologists, pediatric oncology nurses, and data managers to determine the methods of dose reduction currently in use for patients (a) with weight loss, (b) after amputation, and (c) with further weight loss after amputation. Responses were obtained from 237 of 294 individuals surveyed (80.6%). The most popular method was to dose reduce in proportion to the reduction in BSA in patients with weight loss alone (88%), amputees (60%), and amputees with ongoing weight loss (66%). Other methods were chosen by 7%, 31%, and 24% of participants in each of these clinical settings, respectively. The chosen methods result in a discrepancy of administered doses of up to 37%. Our results highlight the need for the standardization of practice, and the determination of the optimal method of dose reduction after weight loss or amputation.