Patient selection: prostate cancer
Parameters:
(1) ipsilateral hypoechoic nodule
(2) ipsilateral digital rectal exam (DRE) positivity
(3) age in years over a range from 50 to 80 years
(4) ipsilateral maximum percent of a core showing tumor
(5) ipsilateral number of cores positive
(6) ipsilateral Gleason group
(7) serum PSA in ng/mL from 1 to 20
points for age =
= (3.333 * (age)) - 166.6667
points for ipsilateral maximum percent of a core =
= MAX(0, (1.01444*(percent)) - 10.14444)
points for ipsilateral number of cores positive =
= MAX(0, (1.242857*(percent)) - 12.42857)
points for serum PSA =
= (2.526 * (PSA)) - 2.526
|
Parameter
|
Finding
|
Points
|
|
ipsilateral hypoechoic nodule
|
no
|
0
|
|
|
yes
|
7.5
|
|
ipsilateral DRE positive
|
no
|
0
|
|
|
yes
|
18
|
|
ipsilateral Gleason group
|
1 (score <= 6, PIN)
|
0
|
|
|
2 (score 3+4)
|
64
|
|
|
3 (score 4+3)
|
79
|
|
|
4 (score 8 to 10)
|
100
|
total score =
= SUM(points for all 7 parameters)
Interpretation:
• minimum score: 0
• maximum score: 451.8
value of X =
= (0.017704 * (score)) - 4.3192
probability of ipsilateral extraprostatic extension for a score LTE 292 =
= 1 / (1 + EXP((-1) * X))
For a score > 292 the probability is > 70%.
Performance:
• The area under the ROC curve is 0.88 for the derivation and 0.74 for the validation cohorts.
