Editing Body surface area (section)

{{Short description|Drug calculating formula}}
In [[physiology]] and [[medicine]], the '''body surface area''' ('''BSA''') is the measured or calculated [[surface area]] of a [[human body]]. For many clinical purposes, BSA is a better indicator of metabolic mass than [[body weight]] because it is less affected by abnormal adipose mass. Nevertheless, there have been several important critiques of the use of BSA in determining the dosage of medications with a narrow [[therapeutic index]], such as [[chemotherapy]].

Typically there is a 4–10 fold variation in [[drug clearance]] between individuals due to differing the activity of [[drug elimination]] processes related to genetic and environmental factors. This can lead to significant overdosing and underdosing (and increased risk of disease recurrence). It is also thought to be a distorting factor in [[Clinical trial#Phases|Phase I and II trials]] that may result in potentially helpful medications being prematurely rejected.<ref>{{cite journal |author=Gurney H |title=How to calculate the dose of chemotherapy |journal=Br. J. Cancer |volume=86 |issue=8 |pages=1297–302 |date=April 2002 |pmid=11953888 |pmc=2375356 |doi=10.1038/sj.bjc.6600139 }}</ref><ref>{{cite journal |vauthors=Gao B, Klumpen HJ, Gurney H |title=Dose calculation of anticancer drugs |journal=Expert Opin Drug Metab Toxicol |volume=4 |issue=10 |pages=1307–19 |date=October 2008 |pmid=18798700 |doi=10.1517/17425255.4.10.1307|s2cid=73327796 }}</ref> The trend to [[personalized medicine]] is one approach to counter this weakness.