Table 4. Multivariate Cox regression of biochemical progression-free survival.

Step	Parameter	HR (95% CI)	P value
First step
	Age	1.000 (0.957-1.045)	0.997
	PSA	1.043 (0.941-1.157)	0.422
	PSAD (> 0.15 vs. ≤ 0.15)	2.939 (1.255-6.882)	0.013
	PPC (≤ 50 vs. > 50)	1.439 (0.696-2.973)	0.326
	Gleason score (7 vs. ≤ 6)	0.523 (0.165-1.657)	0.271
	ADT	0.618 (0.308-1.239)	0.175
	BED	1.003 (0.993-1.012)	0.562
	Clinical stage		0.033
	T1c (Ref.)
	T2a	2.078 (1.149-3.759)	0.016
	T2b	2.337 (0.773-7.065)	0.132
Last step
	PSAD (> 0.15 vs. ≤ 0.15)	3.463 (1.628-7.364)	0.001
	Gleason score (7 vs. ≤ 6)	0.375 (0.135-1.061)	0.065
	Clinical stage		0.016
	T1c (Ref.)
	T2a	2.176 (1.212-3.907)	0.009
	T2b	2.621 (0.908-7.567)	0.075

HR = hazard ratio; CI = confidence interval; PSA = prostate-specific antigen; PSAD = PSA density; ADT = androgen deprivation therapy; BED = biological effective dose; PPC = percent of positive cores.