Table 3.

Correlation of FRV with primary tumor control

	FRV1	FRV2	FRV3
Below FRV cutpoint vs. Above FRV cutpoint	97.3% vs. 73.0%	98.3% vs. 55.8%	100.0% vs. 54.8%
p (Kaplan-Maier)	0.003	7.3 × 10−8	2.0 × 10−8
p (Mann-Whitney)	0.002	1.0 × 10−7	1.5 × 10−8

Abbreviation: FRV = functional risk volume.

The FRV cutpoints, determined by receiver operator characteristic analysis to differentiate between favorable and poor outcomes, are 20 cm³ (FRV₁), 13 cm³ (FRV₂), and 5 cm³ (FRV₃), derived from DCE-MR obtained before, at 2–2.5 weeks, or 4–5 weeks into treatment, respectively. Intratreatment FRV₂ and FRV₃, which are obtained after exposure to cytotoxic treatment, show larger deferences than FRV₁ in the predicted tumor treatment outcome.