Critical assessment of tools to predict clinically insignificant prostate cancer at radical prostatectomy in contemporary men.
BACKGROUND
Overtreatment of prostate cancer (PCa) is a concern, especially in patients who might qualify for the diagnosis of insignificant prostate cancer (IPCa). The ability to identify IPCa prior to definitive therapy was tested.


METHODS
In a cohort of 1132 men a nomogram was developed to predict the probability of IPCa. Predictors consisted of prostate-specific antigen (PSA), clinical stage, biopsy Gleason sum, core cancer length and percentage of positive biopsy cores (percent positive cores). IPCa was defined as organ-confined PCa (OC) with tumor volume (TV) <0.5 cc and without Gleason 4 or 5 patterns. Finally, an external validation of the most accurate IPCa nomogram was performed in the same group.


RESULTS
IPCa was pathologically confirmed in 65 (5.7%) men. The 200 bootstrap-corrected predictive accuracy of the new nomogram was 90% versus 81% for the older nomogram. However, in cutoff-based analyses of patients who were qualified by our and the older nomograms as high probability for IPCa, respectively 63% and 45% harbored aggressive PCa variants at radical prostatectomy (Gleason score 7-10, ECE, SVI, and/or LNI).


CONCLUSIONS
Despite a high accuracy, currently available models for prediction of IPCa are incorrect in 10% to 20% of predictions. The rate of misclassification is even further inflated when specific cutoffs are used. As a consequence, extreme caution is advised when statistical tools are used to assign the diagnosis of IPCa.
Chun
Felix K-H
FK
Department of Urology, University of Hamburg, Hamburg, Germany.
Haese
Alexander
A
Ahyai
Sascha A
SA
Walz
Jochen
J
Suardi
Nazareno
N
Capitanio
Umberto
U
Graefen
Markus
M
Erbersdobler
Andreas
A
Huland
Hartwig
H
Karakiewicz
Pierre I
PI
D001706:Biopsy; D006801:Humans; D008297:Male; D049451:Nomograms; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery; D018570:Risk Assessment; D047368:Tumor Burden
D017430:Prostate-Specific Antigen