Re-calibration and external validation of an existing nomogram to predict aggressive recurrences after radical prostatectomy.
OBJECTIVE
To re-calibrate the previously published Duke Prostate Center (DPC) nomogram for the prediction of biochemical recurrence (BCR) after radical prostatectomy (RP) to not only predict overall BCR but also the clinically more relevant endpoint of an aggressive recurrence (i.e. a BCR with a postoperative PSA doubling time (PSADT) of <9 months).


METHODS
Using the established point-scale system based upon the previously published DPC nomogram, we re-calibrated this point system to predict not just BCR, but also aggressive BCR within 2599 men treated with RP from the DPC database. PSADT was computed on all patients meeting the recurrence definition who had a minimum of two PSA values, separated by at least 3 months, and < or =2 years after recurrence. External validation was performed using data from 1695 men treated with RP within the Shared Equal Access Regional Cancer Hospital (SEARCH) database by calculating the concordance index c and by plotting calibration curves.


RESULTS
The median follow-up for patients with no BCR was 56 and 47 months for DPC and SEARCH, respectively. In the DPC modelling cohort and the SEARCH validation cohort, 645 (25%) and 557 (33%) men had BCR, while 83 (3.2%) and 71 (4.2%) patients had an aggressive recurrence. In external validation, predictive accuracy for an aggressive BCR was high (c = 0.83) and the nomogram showed good calibration.


CONCLUSIONS
We re-calibrated an existing nomogram to not only predict overall BCR after RP but also aggressive recurrence after RP. Our new tool can provide valuable information for patient counselling and patient selection for adjuvant therapy trials.
Schroeck
Florian R
FR
Division of Urologic Surgery, Department of Surgery, and Duke Prostate Center, Duke University School of Medicine, Durham, NC 27710, USA.
Kattan
Michael W
MW
Moul
Judd W
JW
Aronson
William J
WJ
Presti
Joseph C
JC
Terris
Martha K
MK
Kane
Christopher J
CJ
Amling
Christopher L
CL
Sun
Leon
L
Freedland
Stephen J
SJ
D000368:Aged; D004812:Epidemiologic Methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D049451:Nomograms; D011467:Prostate / Q000473:pathology*; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery