International validation of a preoperative nomogram for prostate cancer recurrence after radical prostatectomy.
OBJECTIVE
We evaluated the predictive accuracy of a recently published preoperative nomogram for prostate cancer that predicts 5-year freedom from recurrence. We applied this nomogram to patients from seven different institutions spanning three continents.


METHODS
Clinical data of 6,754 patients were supplied for validation, and 6,232 complete records were used. Nomogram-predicted probabilities of 60-month freedom from recurrence were compared with actual follow-up in two ways. First, areas under the receiver operating characteristic curves (AUCs) were determined for the entire data set according to several variables, including the institution where treatment was delivered. Second, nomogram classification-based risk quadrants were compared with actual Kaplan-Meier plots.


RESULTS
The AUC for all institutions combined was 0.75, with individual institution AUCs ranging from 0.67 to 0.83. Nomogram predictions for each risk quadrant were similar to actual freedom from recurrence rates: predicted probabilities of 87% (low-risk group), 64% (intermediate-low-risk group), 39% (intermediate-high-risk group), and 14% (high-risk group) corresponded to actual rates of 86%, 64%, 42%, and 17%, respectively. The use of neoadjuvant therapy, variation in the prostate-specific antigen recurrence definitions between institutions, and minor differences in the way the Gleason grade was reported did not substantially affect the predictive accuracy of the nomogram.


CONCLUSIONS
The nomogram is accurate when applied at international treatment institutions with similar patient selection and management strategies. Despite the potential for heterogeneity in patient selection and management, most predictions demonstrated high concordance with actual observations. Our results demonstrate that accurate predictions may be expected across different patient populations.
Graefen
Markus
M
Department of Urology, Division of Solid Tumor Oncology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
Karakiewicz
Pierre I
PI
Cagiannos
Ilias
I
Quinn
David I
DI
Henshall
Susan M
SM
Grygiel
John J
JJ
Sutherland
Robert L
RL
Stricker
Phillip D
PD
Klein
Eric
E
Kupelian
Patrick
P
Skinner
Donald G
DG
Lieskovsky
Gary
G
Bochner
Bernard
B
Huland
Hartwig
H
Hammerer
Peter G
PG
Haese
Alexander
A
Erbersdobler
Andreas
A
Eastham
James A
JA
de Kernion
Jean
J
Cangiano
Thomas
T
Schröder
Fritz H
FH
Wildhagen
Mark F
MF
van der Kwast
Theo H
TH
Scardino
Peter T
PT
Kattan
Michael W
MW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery*; D012372:ROC Curve; D012307:Risk Factors; D016019:Survival Analysis