Table 5.

Biochemical failure-free survival (BFFS) in subgroups

Subgroups	Total	Events	Univariate analysis				Multivariate analysisc
			3-year BFFS (%)	5-year BFFS (%)	7-year BFFS (%)	p-valuea	RR (95% CI)	p-valueb
All patientsb	2237	207	95.7	91.9	88.5
NCCN risk group classification
Low risk	1485	93	97.0	94.8	92.8	<0.001	1
Intermediate risk	582	91	93.8	86.0	78.4		2.60 (1.93–3.51)	<0.0001
High risk	41	10	78.9	73.0	73.0		3.02 (1.38–6.60)	0.006
V100 (%)
<90%	642	77	95.3	90.1	86.4	0.03	1
≥90%	1582	128	96.0	92.8	89.5		0.76 (0.55–1.04)	0.09
D90 (% of the prescribed dose)
<90%	668	62	95.8	91.1	89.1	0.49	1
≥90%	1555	143	95.8	92.3	88.5		1.01 (0.72–1.42)	0.93
Neoadjuvant AD therapy
No	1099	96	96.3	92.6	89.2	0.59	1
Yes	882	80	95.8	92.0	89.1		0.79 (0.58–1.07)	0.13
Radioactive isotope
125I	2185	202	95.7	91.9	85.5	0.45	1
103Pd	52	5	96.1	91.7	89.1		0.92 (0.37–2.25)	0.85
Age (years)
<55	102	7	96.9	95.7	90.9	0.42	1
55–64	637	56	94.6	93.4	90.8		1.31 (0.59–2.88)	0.51
65–74	1187	112	96.3	91.5	88.0		1.38 (0.64–2.97)	0.42
≥75	311	32	95.2	88.7	84.7		1.50 (0.65–3.46)	0.34
Interactionsd
NCCN risk group–V100
≥90% vs <90% (low-risk group)							0.53 (0.33–0.84)	0.04
≥90% vs <90% (intermediate-/high-risk group)							1.09 (0.69–1.74)
NCCN risk group–neoadjuvant AD therapy
AD therapy vs no AD therapy (low-risk group)							0.56 (0.35–0.89)	0.07
AD therapy vs no AD therapy (intermediate-/high-risk group)							1.09 (0.69–1.71)
NCCN risk group–radioactive isotope
103Pd vs125I (low-risk group)							0.43 (0.10–1.76)	0.10
103Pd vs125I (intermediate-/high-risk group)							2.34 (0.72–7.61)

¹²⁵I, iodine-125; ¹⁰³Pd, palladium-103; AD, androgen deprivation; CI, confidence interval; D₉₀, dose received by 90% of target volume; NCCN, National Comprehensive Cancer Network; RR, relative risk; V₁₀₀; target volume receiving 100% of prescribed dose.

The sum of the number of patients among levels of a variable could be not equal to the total number of patients (N = 2237).

The “not available (N/A)” subgroups, although included both in univariate and multivariate models, have not been shown in this table.

^aLog-rank test for univariate analysis.

^bWald test from Cox regression multivariate model.

^cIncludes NCCN risk group, V₁₀₀, D₉₀, neoadjuvant AD therapy, radioactive isotope, age and prostatic volume at implantation.

^dIncludes the same variables of ^c plus the interaction term.