465 / 1068
Therapeutic ratio (I)
Easy to interpret: if TCP and NTCP are statistically independent,
this is the probability of being cured without a complication
Has been used in several published studies
The same relative change in NTCP will have a much larger
)
1(
NTCP
TCP P
− ⋅
=
+
influence on P
+
for large NTCP relative to small NTCP
Face validity for non-fatal complications?
A: TCP=40% and NTCP=40%
⇒
R=24%
B: TCP=60% and NTCP=60%
⇒
R=24%
…but proportion of patients with tumor control AND side-effects is
16% with treatment A versus 36% with treatment B