Triage of low-risk prostate cancer patients with PSA levels 10 ng/ml or less: comparison of apparent diffusion coefficient value and transrectal ultrasound-guided target biopsy.
OBJECTIVE
The purpose of our study was to identify low-risk prostate cancer on the basis of the D'Amico clinical risk score in patients with prostate-specific antigen (PSA) levels 10 ng/mL or less who had undergone radical prostatectomy by comparing apparent diffusion coefficient (ADC) with transrectal ultrasound (TRUS)-guided target biopsy.


METHODS
In the preliminary study, we used receiver operating characteristic (ROC) analysis and determined the cutoff ADC to identify prostate cancer with a Gleason score of 6 or less for 117 patients. In the primary study, we assessed the combination of routine MRI (T2-weighted and diffusion-weighted imaging) plus the cutoff ADC value ("method A") to identify low-risk prostate cancer for another 89 patients. Their diagnostic value was compared with that of routine MRI combined with the Gleason score obtained from TRUS-guided target biopsies ("method B").


RESULTS
The preliminary study showed that a mean ADC of 1.04 × 10(-3) mm(2)/s was the best cutoff. In the primary study, accuracy was statistically higher with method A for each reader (p = 0.041).


CONCLUSIONS
In patients with PSA levels 10 ng/mL or less, the combination of MRI findings plus the cutoff ADC is significantly more accurate for the identification of low-risk prostate cancer than is the combination of MRI followed by TRUS-guided target biopsy.
1 Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto, 860-8556, Japan.
Ryo
R
Itatani
Tomohiro
T
Namimoto
Hiroo
H
Kajihara
Kazuhiro
K
Katahira
Kosuke
K
Kitani
Yasuyuki
Y
Hamada
Yasuyuki
Y
Yamashita
D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012007:Rectum; D012189:Retrospective Studies; D018570:Risk Assessment; D014218:Triage / Q000379:methods*; D014463:Ultrasonography
D017430:Prostate-Specific Antigen