We investigated a correlation of serum prostate specific antigen (PSA) and preoperative prostatic volume measured by transrectal ultrasonography(TRUS) in 66 patients with pathologically confirmed benign prostatic hyperplasia (BPH), as aids in the
early
detection of prostate cancer and in the improvement of specificity in BPH. The preoperative serum PSA value was also measured in 18 patients with pathologically confirmed prostate cancer and 15 men without prostatic disease as normal control
using
Tandem-R PSA radioimmunometric assay.
There was a highly significant correlation between natural logarithm transformed PSA(In PSA) and non-transformed prostatic volume by linear regression analysis(r=0.6658, p<0.0001). Given above data, we determined a volume adjusted 95th percentile
upper
confidence limit for In PSA as an appropriate cutoff between normal and abnormal PSA value, according to prostatic volume in BPH. In the patients with BPH and prostate cancer, sensitivity, specificity, diagnostic accuracy and positive predictive
value
were 94%, 72%, 68% and 48%, respectively. A statistical results by the volume-adjusted cutoff for In PSA was similar to that at 10ng/ml as cutoff for PSA value. Above 40ml in prostatic volume, however, a false positive rate was decreased in
inverse
proportion to prostatic volume in BPH.
In summary, the prostatic volume must be considered in BPH patients with elevated serum PSA value, negative digital rectal examination and negative TRUS of prostate. And when the volume adjusted PSA cutoff is clinically applied to BPH patients
for
the
early detection of prostate cancer, we thought that the false positive rate can be decreased in BPH patients.
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