Serum pro-prostate specific antigen preferentially detects aggressive prostate cancers in men with 2 to 4 ng/ml prostate specific antigen.
OBJECTIVE
Pro forms of prostate specific antigen (PSA) have been reported to be more cancer specific markers of prostate cancer than total PSA and they also may preferentially detect the more aggressive forms of the disease.


METHODS
Research immunoassays with high specificity for pro-PSA forms were used to study 1091 retrospective serum specimens, including 555 with 2 to 4 and 536 with 4 to 10 ng/ml PSA, from men enrolled in prostate cancer screening studies who underwent prostate biopsy.


RESULTS
In the 2 to 4 ng/ml PSA range the ratio of pro- to free-PSA (percent pro-PSA) using a cutoff of 1.8% for recommending prostate biopsy detected 90% of cancers, including 16 of 16 extracapsular tumors and 28 of 29 tumors with a pathology Gleason score of 7 or greater, while avoiding 19% of unnecessary biopsies. Serum percent pro-PSA was significantly increased for Gleason score 7 or greater vs less than 7 (p = 0.0018). In the PSA range of 4 to 10 ng/ml percent pro-PSA had the highest cancer specificity, avoiding 31% of unnecessary biopsies, while detecting 34 of 35 cancers with a pathology Gleason score of 7 or greater and 29 of 31 extracapsular tumors. Neither percent free PSA nor complexed PSA enhanced the detection of aggressive cancers in the 4 to 10 ng/ml PSA range.


CONCLUSIONS
Percent pro-PSA was superior to percent free and calculated complexed PSA for the detection of prostate cancer in the PSA range of 2 to 10 ng/ml and it had selectivity for detecting more aggressive cancers, as indicated by Gleason score 7 or greater and/or extracapsular tumor extension.
Catalona
William J
WJ
Washington University, St Louis, Missouri, USA.
Bartsch
Georg
G
Rittenhouse
Harry G
HG
Evans
Cindy L
CL
Linton
Harry J
HJ
Horninger
Wolfgang
W
Klocker
Helmut
H
Mikolajczyk
Stephen D
SD
D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology*; D012189:Retrospective Studies
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen