Background Chemotherapy drug dosing in adult patients with cancer has traditionally been based on patient’s estimated body surface area (BSA). BSA can be calculated using several standard formulas and none of them is recommended above the others.

Purpose To assess the variation in BSA calculated in oncology patients using different validated formulas.

Material and methods All patients receiving chemotherapy in our hospital, whose weight and height were recorded, were included. BSA was calculated for all patients using six formulas (DuBois, Mosteller, Gehan and George, Haycock, Fujimoto and Takahira). All calculated BSAs were compared against DuBois BSA, as this is the most widely-used formula.

Results In 55 months, a total of 1,868 patients was included. 1,192 (63.8%) were overweight patients (BMI ≥ 25.00) and 32 (1.71%) were underweight (BMI < 18.50).

Conclusion There are remarkable differences in values of BSA depending on the formula used to calculate it, especially at the extremes of BMI. This may result in great differences in dosing, especially in overweight patients. Therefore, when calculating BSA, the formula used should always be stated.

References and/or Acknowledgements No conflict of interest.