The potential role of prebiopsy magnetic resonance imaging combined with prostate-specific antigen density in the detection of prostate cancer.
OBJECTIVE
Two-thirds of patients with a gray-zone prostate-specific antigen (PSA) level undergo unnecessary biopsy. Sensitivity is not yet sufficient to permit the use of modified PSA parameters or magnetic resonance (MR) imaging alone for prostate cancer screening. Thus, we evaluated the combination of MR imaging and PSA density (PSAD) for specificity and sensitivity.


METHODS
During the period April 2004 through March 2006, 185 patients with a PSA level of 4.0-10.0 ng/mL underwent MR imaging and transrectal ultrasonography-guided 8-core biopsy (systemic sextant biopsy of the peripheral zone plus two cores of transition zone). All MR images were interpreted prospectively by two radiologists. An image was considered positive for prostate cancer if any feature indicated a cancerous lesion. Receiver operating characteristic (ROC) curves were used to compare the usefulness of the PSA level, PSAD and PSA transitional zone density (PSATZ) for the detection of prostate cancer.


RESULTS
Of the 185 patients, 62 had prostate cancer. Sensitivity and specificity of the axial T2-weighted MR imaging findings for cancer detection were 79.0% and 59.4%, respectively. The area under the ROC curve was 0.590 for the PSA level, 0.718 for PSAD and 0.695 for PSATZ. MR imaging findings and PSAD were shown by multivariate analysis to be statistically significant independent predictors of prostate cancer (P < 0.001). With a PSAD cut-off value of 0.111, sensitivity was 96.8%, but specificity was 19.5%. Combining MR imaging findings with PSAD increased the specificity to 40% and retained 95% sensitivity.


CONCLUSIONS
MR imaging findings combined with PSAD provide high sensitivity and improve the specificity for the early detection of prostate cancer.
Kubota
Yasuaki
Y
Department of Urology, Gifu University School of Medicine, Gifu, Japan. kubomitu@zj8.so-net.ne.jp
Kamei
Shingo
S
Nakano
Masahiro
M
Ehara
Hidetoshi
H
Deguchi
Takashi
T
Tanaka
Osamu
O
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity
D017430:Prostate-Specific Antigen