Development of a nomogram for predicting a positive repeat prostate biopsy

Table 1 Clinical and pathological characteristics n (%)

Predictor variables		No cancer	Cancer	P value
		n = 675	n = 132
Digital rectal ex- amination	Negative	642 (95.1)	122 (92.4)	0.209
	Positive	33 (4.9)	10 (7.6)
TRUS	Negative	603 (89.3)	108 (81.8)	0.015
	Positive	72 (10.7)	24 (18.2)
HGPIN in previous biopsy	Negative	648 (96)	121 (91.7)	0.032
	Positive	27 (4)	11 (8.3)
ASAP in previous biopsy	Negative	627 (92.9)	116 (87.9)	0.051
	Positive	48 (7.1)	16 (12.1)
Age, yr	Mean	67	68.8	0.008
	SD	7.3	6.3
No. of previous biopsy sessions	Mean	1.7	1.7	0.894
	SD	1	1.1
No. of biopsy cores	Mean	11.3	11.9	0.006
	SD	2.4	2.5
Cumulative No. of cores	Mean	16.1	15.8	0.791
	SD	12.3	11.4
Months from the initial biopsy	Mean	26.8	25.7	0.576
	SD	21.0	22.7
Months from the previous biopsy	Mean	16.9	15.7	0.353
	SD	13.7	13.6
PSA slope (ng/mL per year)	Mean	1.2	1.3	0.824
	SD	5.7	13.2
PSA (ng/mL)	Mean	9.8	11.6	0.011
	SD	6.7	9.8
Prostate volume (cc)	Mean	53.0	43.8	< 0.001
	SD	25.8	27.2
TZ prostate volume (cc)	Mean	30.2	21.2	< 0.001
	SD	20.4	17.9
PSA density (ng/mL per cc)	Mean	0.2	0.3	< 0.001
	SD	0.2	0.4
PSA TZ density (ng/mL per cc)	Mean	0.4	0.8	< 0.001
	SD	0.4	0.9

TRUS: Transrectal ultrasonography; HGPIN: High grade prostatic intraepithelial neoplasia; ASAP: Atypical small acinar proliferation; TZ: Transitional zone.

Table 2 Association between cancer detection rates and clinical variables according to the number of biopsy sessions

Variable	Total No./No. Ca (%)
	Biopsy 2	Biopsy 3	Biopsy 4	Biopsy 5
	459/75(16.3)	208/34 (16.7)	82/15(18)	41/3(7)
Digital rectal examination
Negative	437/73 (16.7)	195/29(14.9)	76/12 (15.8)	40/3 (7.5)
Positive	22/2 (9.1)	13/5(38.5)	6/3 (50)	1/0 (0)
Prostate volume on TRUS, (cc)
Less than 20	15/7 (47.7)	6/4 (66.7)	0/0 (0)	0/0 (0)
20-40	181/39 (21.5)	69/12 (17.4)	24/6 (25.0)	14/1 (7.1)
40-60	145/19 (13.1)	75/12 (16.0)	35/5 (14.3)	16/2 (12.5)
60-80	71/7 (9.9)	32/6 (18.8)	13/2 (15.4)	5/0 (0)
80 or Greater	47/3 (6.3)	26/0 (0)	10/2 (20.0)	6/0 (0)
PSA density (ng/mL per cc)
Less than 0.15	196/16 (8.2)	82/11 (13.4)	29/6 (20.7)	10/0 (0)
0.15-0.30	185/33 (17.8)	84/10 (11.9)	36/6 (16.7)	22/3 (13.6)
0.30-0.45	46/14 (30.4)	20/3 (15.0)	10/1 (10.0)	7/0 (0)
Greater than 0.45	32/12 (38.5)	22/10 (45.5)	7/2 (28.6)	2/0 (0)
PSA TZ density (ng/mL per cc)
Less than 0.25	156/9 (5.8)	58/7 (12.1)	19/3 (18.8)	10/0 (0)
0.25-0.5	168/22 (13.1)	85/11 (12.9)	42/7 (16.7)	18/2 (22.2)
0.5-1.0	98/26 (26.5)	40/6 (15.0)	15/3 (20.0)	12/2 (18.3)
Greater than 1.0	37/18 (48.6)	25/10 (40.0)	6/2 (33.3)	1/0 (0)
PSA (ng/mL)
Less than 4	18/1 (5.6)	1/1 (100)	0/0 (0)	0/0 (0)
4-10	313/48 (15.3)	136/19 (14.0)	49/8 (16.3)	20/2 (10.0)
10-20	108/21 (19.4)	54/11 (20.3)	25/5 (20.0)	17/1 (5.9)
Greater than 20	20/5 (25.0)	17/3 (17.6)	8/2 (25.0)	4/0 (0)
PSA slope (ng/mL per year)
Less than 0.75	237/30 (12.7)	102/15 (14.7)	44/8 (18.2)	21/1 (4.8)
0.75 or greater	222/45 (20.3)	106/19 (17.9)	38/7 (18.4)	20/2 (10.0)
Previous HGPIN
Negative	437/67 (15.3)	200/32 (16.0)	79/14 (17.7)	40/3 (7.5)
Positive	22/8 (36.4)	8/2 (25.0)	3/1 (33.3)	1/0 (0)
Previous ASAP
Negative	427/68 (15.9)	190/30 (15.8)	75/13 (17.3)	38/2 (5.3)
Positive	32/7 (21.9)	18/4 (22.2)	7/2 (28.6)	3/1 (33.3)
Normal histology	406/61 (15.0)	184/29 (15.8)	72/12 (16.7)	37/2 (5.4)
Total	459/75 (16.3)	208/34 (16.4)	82/15 (18.3)	41/3 (7.3)

Results of cases with 6 or more biopsy sessions are not shown because of low numbers. HGPIN: High grade prostatic intraepithelial neoplasia; TZ: Transitional zone; ASAP: Atypical small acinar proliferation.

Table 3 Multivariable logistic regression analysis in predicting positive repeat biopsy with generalized estimating equations adjustment for clustering repeat biopsies from the same patients

Predictor variables	Q1	Q3	Odds ratio	Lower 0.95	Upper 0.95	P
Age, yr	62	73	1.6	1.1	2.5	0.002
No. of previous biopsy sessions	1	2	2.3	0.8	6.2	0.002
No. of biopsy cores	10	12	1.6	1.3	2.1	0.001
Cumulative No. of cores	8	20	0.3	0.1	0.8	0.001
Months from the initial biopsy	10.3	36	0.6	0.2	2.0	0.727
Months from the previous biopsy	7.1	22.7	1.5	0.6	3.8	0.651
PSA slope (ng/mL per year)	-0.3	2.4	0.9	0.9	1.0	0.007
PSA (ng/mL)	6	11.4	1.0	0.3	4.0	0.098
Prostate volume (cc)	33.5	60.5	3.3	0.5	20.8	0.081
TZ prostate volume (cc)	15	36.1	0.1	0.0	1.0	0.116
PSA density (ng/mL per cc)	0.1	0.3	2.5	0.3	24.7	0.045
PSA TZ density (ng/mL per cc)	0.2	0.6	0.8	0.1	6.9	0.328
DRE-positive: negative	NA	NA	0.7	0.3	1.7	0.393
TRUS-positive: negative	NA	NA	1.4	0.8	2.6	0.218
HGPIN-positive: negative	NA	NA	2.2	0.9	5.2	0.080
ASAP-positive: negative	NA	NA	2.2	1.1	4.7	0.035

TRUS: Transrectal ultrasonography; HGPIN: High grade prostatic intraepithelial neoplasia; ASAP: Atypical small acinar proliferation; TZ: Transitional zone; PSA: Prostatic specific antigen; DRE: Digital rectal exam.

Table 4 Published nomograms to predict positive prostate biopsy in repeat biopsy

Ref.	No. of patients	AUC	AUC of external validation	No of factors	Nomogram factors	Mean of no of biopsy cores	Ca detection rate, %
Lopez-Corona et al[9,12]	343	0.700	0.710	8	Standard factors + PSAV, HGPIN, ASAP, No. of total cores, biopsy history, family history	9.15	20
2Walz et al[10]	161	0.720	-	9	Age, PSA, %free PSA, PSA density, TZ density, prostate volume, TZ volume, no of previous biopsy, no of cores.	24	41
Chun et al[11]	1082	0.760	0.68-0.78	6	Standard factors, prostate volume, biopsy history, %free PSA, sampling density	11.1	30.2
Benecchi et al[13]	419	-	0.856	7	DRE + PSA slope, HGPIN, %free PSA, PSA density	-	31
Rochester et al[14]	110	0.818	0.696	7	Standard factors + PSA velocity, HGPIN, biopsy history, %free PSA	-	30-31
Chun et al[15,16]	809	0.700	0.73-0.751	6	Standard factors + prostate volume, biopsy history, PCA3	15	39.1
Moussa et al[17]	408	0.720	0.620	12	Standard factors + prostate volume, PSA velocity, HGPIN, ASAP, No. of total cores, family history, time from initial/previous biopsy, BMI	19.1	31.6
2Sakura et al[18]	515	0.791	-	5	Age, %free PSA, prostate volume, previous extended biopsy, PSA doubling time	26	31.6
Present series	459	0.740	-	16	Age, No. of biopsy core, PSA, PSA density, prostate volume, TZ volume, PSA TZ density, TRUS, DRE, HGPIN, ASAP, months from initial biopsy and previous biopsy, No. of previous negative biopsy, PSA slope	11.4	17

¹Standard factors include age, PSA and digital rectal examination;

²Extended biopsy. AUC: Area under the curves; TZ: Transitional zone; TRUS: Transrectal ultrasonography; HGPIN: High grade prostatic intraepithelial neoplasia; ASAP: Atypical small acinar proliferation; PSA: Prostatic specific antigen,DRE: Digital rectal exam; BMI: Body-mass index.