Long-term prediction of prostate cancer: prostate-specific antigen (PSA) velocity is predictive but does not improve the predictive accuracy of a single PSA measurement 15 years or more before cancer diagnosis in a large, representative, unscreened population.
OBJECTIVE
We tested whether total prostate-specific antigen velocity (tPSAv) improves accuracy of a model using PSA level to predict long-term risk of prostate cancer diagnosis.


METHODS
During 1974 to 1986 in a preventive medicine study in Sweden, 5,722 men aged <or= 50 gave two blood samples about 6 years apart. We measured free (fPSA) and total PSA (tPSA) in archived plasma samples from 4,907 participants. Prostate cancer was subsequently diagnosed in 443 (9%) men. Cox proportional hazards regression was used to evaluate tPSA and tPSAv as predictors of prostate cancer. Predictive accuracy was assessed by the concordance index.


RESULTS
The median time from second blood draw to cancer diagnosis was 16 years; median follow-up for men without prostate cancer was 21 years. In univariate models, tPSA level at second assessment and tPSAv between first and second assessments were associated with prostate cancer (both P < .001). tPSAv was highly correlated with tPSA level (r = 0.93). Twenty-year probabilities of cancer for men at 50th, 90th, and 95th percentile of tPSA and tPSAv were 10.6%, 17.1%, and 21.2% for tPSA, and 9.1%, 11.8%, and 14.1% for tPSAv, respectively. The concordance index for tPSA level was 0.771. Adding tPSAv, fPSA, %fPSA or velocities of fPSA and %fPSA did not importantly increase accuracy of tPSA to predict prostate cancer. Results were unchanged if the analysis was restricted to patients with advanced cancer at diagnosis.


CONCLUSIONS
Although PSA velocity is significantly increased in men with prostate cancer up to two decades before diagnosis, it does not aid long-term prediction of prostate cancer.
Ulmert
David
D
Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Serio
Angel M
AM
O'Brien
Matthew F
MF
Becker
Charlotte
C
Eastham
James A
JA
Scardino
Peter T
PT
Björk
Thomas
T
Berglund
Göran
G
Vickers
Andrew J
AJ
Lilja
Hans
H
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D012107:Research Design; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen