Table 2.

Factors associated with any PSM, specific PSM sites, and multiple PSM sites derived from multivariable logistic regression models (1998–2016).

Factor	Any PSM			Apex			Bladder neck			Posterolateral			Multiple PSM sites
	OR	95% CI	p-Value	OR	95% CI	p-Value	OR	95% CI	p-Value	OR	95% CI	p-Value	OR	95% CI	p-Value
Age at diagnosis, year
<60	1.0	Reference	0.76	1.0	Reference	0.61	1.0	Reference	0.94	1.00	Reference	0.09	1.0	Reference	0.41
60–69	0.9	0.8–1.1	0.46	1.1	0.8–1.4	0.59	0.9	0.6–1.4	0.72	0.8	0.6–1.0	0.08	0.9	0.6–1.4	0.63
70–79	1.0	0.7–1.3	0.75	1.1	0.7–1.7	0.66	1.0	0.6–1.7	0.93	0.7	0.5–1.1	0.10	0.7	0.4–1.4	0.34
Treatment period
≤2007	1.0	Reference	0.17	1.0	Reference	0.22	1.0	Reference	0.002	1.0	Reference	0.020	1.0	Reference	0.97
2008–2010	1.0	0.8–1.2	0.79	0.7	0.5–1.0	0.06	2.0	1.1–3.5	0.020	1.0	0.8–1.4	0.810	1.0	0.6–1.7	0.98
2011–2013	0.6	0.5–0.8	0.01	0.7	0.4–1.1	0.10	2.6	1.4–4.8	0.003	0.5	0.3–0.7	<0.001	0.6	0.3–1.1	0.09
2014–2016	0.8	0.6–1.2	0.31	0.7	0.4–1.1	0.15	3.1	1.7–5.9	0.001	0.7	0.5–1.1	0.140	1.2	0.6–2.1	0.63
Pre-treatment PSA, ng/mL
<5	1.0	Reference	0.39	1.0	Reference	0.20	1.0	Reference	0.89	1.0	Reference	0.78	1.0	Reference	0.73
≥5–<10	0.9	0.7–1.2	0.63	1.1	0.7–1.5	0.79	0.6	0.4–0.9	0.02	1.0	0.7–1.3	0.86	0.7	0.4–1.1	0.14
≥10–20	1.3	0.9–1.7	0.08	1.7	1.1–2.6	0.02	0.9	0.5–1.5	0.73	1.2	0.9–1.7	0.25	1.4	0.8–2.5	0.22
≥20	1.3	0.8–2.3	0.31	1.4	0.8–2.3	0.19	1.2	0.5–2.6	0.68	0.9	0.5–1.7	0.67	1.2	0.5–2.9	0.74
RP Gleason score
≤6	1.0	Reference	0.08	1.0	Reference	0.35	1.0	Reference	0.03	1.0	Reference	0.010	1.0	Reference	0.010
3＋4	1.3	1.0–1.7	0.05	1.3	0.9–1.8	0.23	0.8	0.4–1.3	0.33	1.8	1.3–2.6	<0.001	2.8	1.4–5.7	0.010
4＋3	1.4	1.0–1.9	0.05	1.0	0.7–1.6	0.83	1.2	0.6–2.2	0.63	2.1	1.4–3.1	<0.001	3.6	1.7–7.6	0.001
8	1.5	0.9–2.3	0.10	1.3	0.7–2.5	0.36	1.7	0.8–3.7	0.17	2.1	1.2–3.5	0.006	4.9	2.0–11.4	<0.001
9–10	1.7	1.0–2.7	0.02	1.6	0.8–2.9	0.16	1.4	0.7–3.1	0.35	2.2	1.3–3.9	0.003	3.4	1.4–8.5	0.010
pT
2	1.0	Reference	<0.001	1.0	Reference	0.01	1.0	Reference	<0.001	1.0	Reference	<0.001	1.0	Reference	<0.001
3a	2.3	1.9–2.8	<0.001	1.4	1.0–1.9	0.03	1.9	1.2–3.0	0.004	2.5	2.0–3.2	<0.001	2.1	1.3–3.4	0.001
3b	3.4	2.5–4.7	<0.001	1.9	1.2–2.8	0.003	3.4	2.0–5.8	<0.001	3.4	2.4–4.9	<0.001	4.0	2.3–7.0	<0.001
Tumour volume, per 10 cm3
Q1 (≤1.4)	1.0	Reference	<0.001	1.0	Reference	<0.001	1.0	Reference	<0.001	1.0	Reference	<0.001	1.0	Reference	<0.001
Q2 (>1.4–2.7)	1.3	0.9–1.9	0.10	2.3	1.2–4.5	0.01	2.1	0.8–5.6	0.14	1.2	0.8–1.7	0.47	2.3	0.7–7.2	0.170
Q3 (>2.7–5.4)	1.7	1.2–2.5	<0.001	3.7	2.2–7.5	<0.001	3.0	1.2–7.6	0.02	0.9	0.6–1.4	0.62	1.7	0.5–5.5	0.380
Q4 (>5.4)	2.9	2.0–4.0	<0.001	5.3	2.8–9.9	<0.001	8.9	3.7–20.4	<0.001	1.5	1.0–2.3	0.05	7.8	2.5–20.6	<0.001
Surgeon volumea	0.93	0.88–0.98	0.004	0.96	0.89–1.03	0.26	0.90	0.82–0.97	0.010	0.91	0.87–0.97	0.003	0.85	0.76–0.95	0.003
Nerve-sparing surgery	0.9	0.7–1.2	0.45	1.1	0.7–1.5	0.78	0.7	0.4–1.0	0.070	0.9	0.6–1.1	0.32	0.7	0.4–1.1	0.110

PSM, positive surgical margin; OR, odds ratio; RP, radical prostatectomy; Q, quartile; CI, confidence interval; PSA, prostate-specific antigen; pT, pathological tumor stage.

Note: the “Reference” indicates the reference group for each variable considered.

^aPer 100 previous prostatectomies.