Pattern of prostate-specific antigen (PSA) failure dictates the probability of a positive bone scan in patients with an increasing PSA after radical prostatectomy.
OBJECTIVE
Physicians often order periodic bone scans (BS) to check for metastases in patients with an increasing prostate-specific antigen (PSA; biochemical recurrence [BCR]) after radical prostatectomy (RP), but most scans are negative. We studied patient characteristics to build a predictive model for a positive scan.


METHODS
From our prostate cancer database we identified all patients with detectable PSA after RP. We analyzed the following features at the time of each bone scan for association with a positive BS: preoperative PSA, time to BCR, pathologic findings of the RP, PSA before the BS (trigger PSA), PSA kinetics (PSA doubling time, PSA slope, and PSA velocity), and time from BCR to BS. The results were incorporated into a predictive model.


RESULTS
There were 414 BS performed in 239 patients with BCR and no history of androgen deprivation therapy. Only 60 (14.5%) were positive for metastases. In univariate analysis, preoperative PSA (P = .04), seminal vesicle invasion (P = .02), PSA velocity (P < .001), and trigger PSA (P < .001) predicted a positive BS. In multivariate analysis, only PSA slope (odds ratio [OR], 2.71; P = .03), PSA velocity (OR, 0.93; P = .003), and trigger PSA (OR, 1.022; P < .001) predicted a positive BS. A nomogram for predicting the bone scan result was constructed with an overfit-corrected concordance index of 0.93.


CONCLUSIONS
Trigger PSA, PSA velocity, and slope were associated with a positive BS. A highly discriminating nomogram can be used to select patients according to their risk for a positive scan. Omitting scans in low-risk patients could reduce substantially the number of scans ordered.
Dotan
Zohar A
ZA
Department of Quantitative Health Sciences, The Cleveland Clinic Foundation, 9500 Euclid Avenue/Wb-4, Cleveland, OH 44195, USA. kattanm@ccf.org
Bianco
Fernando J
FJ
Rabbani
Farhang
F
Eastham
James A
JA
Fearn
Paul
P
Scher
Howard I
HI
Kelly
Kevin W
KW
Chen
Hui-Ni
HN
Schöder
Heiko
H
Hricak
Hedvig
H
Scardino
Peter T
PT
Kattan
Michael W
MW
D001842:Bone and Bones / Q000000981:diagnostic imaging*; D016208:Databases, Factual; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D011336:Probability; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis / Q000601:surgery*; D011877:Radionuclide Imaging
D017430:Prostate-Specific Antigen