Evaluating the PCPT risk calculator in ten international biopsy cohorts: results from the Prostate Biopsy Collaborative Group.
OBJECTIVE
To evaluate the discrimination, calibration, and net benefit performance of the Prostate Cancer Prevention Trial Risk Calculator (PCPTRC) across five European randomized study of screening for prostate cancer (ERSPC), 1 United Kingdom, 1 Austrian, and 3 US biopsy cohorts.


METHODS
PCPTRC risks were calculated for 25,733 biopsies using prostate-specific antigen (PSA), digital rectal examination, family history, history of prior biopsy, and imputation for missing covariates. Predictions were evaluated using the areas underneath the receiver operating characteristic curves (AUC), discrimination slopes, chi-square tests of goodness of fit, and net benefit decision curves.


RESULTS
AUCs of the PCPTRC ranged from a low of 56% in the ERSPC Goeteborg Rounds 2-6 cohort to a high of 72% in the ERSPC Goeteborg Round 1 cohort and were statistically significantly higher than that of PSA in 6 out of the 10 cohorts. The PCPTRC was well calibrated in the SABOR, Tyrol, and Durham cohorts. There was limited to no net benefit to using the PCPTRC for biopsy referral compared to biopsying all or no men in all five ERSPC cohorts and benefit within a limited range of risk thresholds in all other cohorts.


CONCLUSIONS
External validation of the PCPTRC across ten cohorts revealed varying degree of success highly dependent on the cohort, most likely due to different criteria for and work-up before biopsy. Future validation studies of new calculators for prostate cancer should acknowledge the potential impact of the specific cohort studied when reporting successful versus failed validation.
Department of Urology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA. ankerst@uthscsa.edu
Donna P
DP
Ankerst
Andreas
A
Boeck
Stephen J
SJ
Freedland
Ian M
IM
Thompson
Angel M
AM
Cronin
Monique J
MJ
Roobol
Jonas
J
Hugosson
J
J
Stephen Jones
Michael W
MW
Kattan
Eric A
EA
Klein
Freddie
F
Hamdy
David
D
Neal
Jenny
J
Donovan
Dipen J
DJ
Parekh
Helmut
H
Klocker
Wolfgang
W
Horninger
Amine
A
Benchikh
Gilles
G
Salama
Arnauld
A
Villers
Daniel M
DM
Moreira
Fritz H
FH
Schröder
Hans
H
Lilja
Andrew J
AJ
Vickers
D000368:Aged; D001707:Biopsy, Needle; D015331:Cohort Studies; D051517:Digital Rectal Examination; D006801:Humans; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods
D017430:Prostate-Specific Antigen