Table 3.

Univariate and multivariate Cox regression analysis determining independent factors influencing biochemical recurrence-free survival for (A) whole cohort and (B) Prostate bed negative on PSMA-PET/CT.

A. Whole cohort n = 394
Variables	Univariate	Multivariate	HR (95% CI)
	P value	P value
Time to BR after primary therapy (≤15, >15 mo)	0.677
Initial T-status (≤T2c, >T2c)	0.018	0.020	1.49 (1.07–2.08)
Initial N-status	0.028
Gleason Score (≤7a, 7b, ≥8)	0.025
Initial PSA (≤10ng/ml, 10-20ng/ml, >20ng/ml)	0.121
Initial risk score	0.689
Local recurrence prostate bed	0.003
M-status at time of recurrence	<0.001	0.001	1.95 (1.32–2.86)
N-status at time of recurrence	0.605
PSA at time of SRT (≤0.5 ng/ml, >0.5 ng/ml)	0.005	0.009	1.53 (1.11–2.10)
Resection margins (R0 vs. R1–2)	0.072
Additive ADT	<0.001	<0.001	0.36 (0.24–0.53)
Elective RT vs. No elective RT	<0.001	0.006	0.33 (0.15–0.73)
Area of elective RT (prostate bed, lymphatics)	<0.001	0.006	1.76 (1.03–3.83)
Radiotherapy technique (Conventional vs. SBRT)	<0.001
B. Prostate bed negative on PSMA-PET/CT n = 278
Variables	Univariate	Multivariate	HR (95% CI)
	P value	P value
Time to BR after primary therapy (≤15, >15mo)	0.701
Initial T-status (≤T2c, >T2c)	0.035	0.009	1.67 (1.14–2.44)
Initial N-status	0.063
Gleason Score (≤7a, 7b, ≥8)	0.31
Initial PSA (≤10 ng/ml, 10–20 ng/ml, >20 ng/ml)	0.633
Initial risk score	0.431
M-status at time of recurrene	<0.001	0.002	2.01 (1.32–3.34)
N-status at time of recurrence	0.036		-
PSA at time of SRT (≤0.5 ng/ml, >0.5 ng/ml)	0.001	0.019	1.56 (1.08–2.25)
Resection margins (R0 vs. R1–2)	0.107
Additive ADT	<0.001	<0.001	0.35 (0.22–0.55)
Elective RT prostate bed	<0.001	0.020	0.59 (0.37–0.92)
Radiotherapy technique (Conventional vs. SBRT)	0.001