Using the receiver operating characteristic curve to select pretreatment and pathologic predictors for early and late postprostatectomy PSA failure.
OBJECTIVE
Pretreatment prostate-specific antigen (PSA), prostatectomy Gleason score, margin status, and pathologic T stage are known explanatory variables for the postprostatectomy PSA outcome. We used the receiver operating characteristic (ROC) curve to select those factors that were optimal for predicting early and late postoperative PSA failure.


METHODS
We designed and implemented a clinical outcome prediction expert that performs, assesses, and optimizes the actuarial prediction on individual cases. A postprostatectomy database of 1022 patients was divided into 60% for training and 40% for validation. The ROC areas of the predictors were calculated over a range of cutoff time from 24 to 60 months.


RESULTS
Multivariate pathologic T stage/prostatectomy Gleason score/margin status had the highest ROC area of 0.900. Patients with Stage T disease less than T3, negative surgical margins, and Gleason score of 6 or less had a 90% probability to be PSA failure free at 4 years versus 36% otherwise. The pathologic T stage/margin status accurately predicted PSA failure at 24 months or less after prostatectomy with an ROC area of 0.800. Lower risk patients (less than Stage T3, negative surgical margins) had a 94% probability to be PSA failure free at 2 years versus 46% otherwise.


CONCLUSIONS
A combination of actuarial analysis and ROC optimization accurately identified the individual patients at high risk of early and late postprostatectomy PSA failure.
Cheung
R
R
Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Altschuler
M D
MD
D'Amico
A V
AV
Malkowicz
S B
SB
Wein
A J
AJ
Whittington
R
R
D000206:Actuarial Analysis; D006801:Humans; D008297:Male; D011336:Probability; D016016:Proportional Hazards Models; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000601:surgery*; D012372:ROC Curve; D015203:Reproducibility of Results; D012306:Risk; D017211:Treatment Failure; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen