Clinical efficacy of prostate cancer detection using power doppler imaging in American and Japanese men.
OBJECTIVE
The aim of this study was to compare the detection rates of tumor vascular flow as measured by power Doppler imaging (PDI) in 2 populations and to determine whether PDI can reduce the number of unnecessary prostate biopsies in men with serum prostate-specific antigen (PSA) concentrations less than 10.1 ng/ml.


METHODS
The patient populations were Japanese (group 1) and American (group 2) men with either serum PSA concentrations of 4.1-10.0 ng/ml or abnormal findings on digital rectal examination (DRE) plus PSA concentrations less than 4.1 ng/ml. We compared the overall diagnostic accuracy of DRE, gray-scale transrectal sonography (TRUS), and PDI between the 2 groups.


RESULTS
In total, 275 men were studied, 154 in group 1 and 121 in group 2. Cancer was identified in 27% of men in group 1 and in 60% of group 2. Men with cancer in both groups differed significantly in age, peripheral zone volume, and mean number of positive biopsy cores. The sensitivity and specificity of PDI in group 2 were significantly inferior to those in group 1. The negative predictive value (NPV) of PDI was significantly higher for group 1 than for group 2. The NPV of PDI in group 1 was equivalent to that for the combination of DRE and TRUS, whereas the NPV for PDI in group 2 was significantly inferior to that of DRE and TRUS.


CONCLUSIONS
Tumor vascularity could be detected by PDI more effectively in Japanese men with cancer than in American men with cancer. We hypothesize that this difference was a result of larger cancer volumes and smaller prostates in the Japanese men. PDI did not provide any performance advantage over DRE and TRUS in avoiding unnecessary biopsies.
Okihara
Koji
K
Department of Urology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 446, Houston, Texas 77030, USA.
Miki
Tsuneharu
T
Joseph Babaian
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D001706:Biopsy / Q000706:statistics & numerical data*; D006801:Humans; D007564:Japan / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000208:ethnology / Q000276:immunology; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color; D014481:United States / Q000208:ethnology; D019564:Unnecessary Procedures / Q000706:statistics & numerical data*
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen