Introduction: Prostatic specific antigen (PSA) is an excellent tumor marker, but it is not specific for prostate cancer. We evaluated the accuracy of PSA adjusted for transition zone volume calculated by transrectal ultrasonography in predicting prostate cancer in men compared with PSA density.

Material and Methods: PSA adjusted for transition zone volume was obtained from 100 patients who underwent transrectal ultrasonographically guided biopsies (50 patients with prostate cancer and 50 patients with BPH). PSA density was calculated by through dividing total serum PSA by total prostate volume, and total serum PSA was divided by transition zone volume to yield PSA adjusted for transition zone volume. The PSA density and PSA adjusted for transition zone volume were compared and analyzed in patients with cancer of prostate and patient with BPH.

Results: 50 fifty patients with BPH, 50 patients with prostate cancer were evaluated. Mean PSA adjusted for transition zone volume and PSA density were 1.17 ± 0.21 and 0.91 ± 0.17 in patients with prostate cancer and 0.65 ± 0.14 and 0.34 ± 0.064 in patients with BPH. PSA adjusted for transition zone volume had sensitivity of 26.6% and specificity of 86.6% and PSA density had sensitivity of 30% and specificity of 93.3% for prostate cancer.

Conclusions: PSA adjusted for transitional zone volume is not more accurate than PSA density in for distinguishing prostate cancer from BPH. Determination of transitional zone volume and total prostate volume by transrectal ultrasonography may be helpful for predicting the probability of positive prostate biopsy results.