Abstract

PSA is the most important tumor marker for the diagnosis of prostatic carcinoma. If 4.0 ng/ml, which is the widely accepted cut-off value, is used, 2/3 of the biopsies are negative. The cases in which the serum PSA is detectable are those “diagnostic gray area of PSA” values between 4.0 and 10 ng/ml. The efforts for increasing the diagnostic value of the PSA for the prostatic carcinoma are currently going on. In this study we compared transitional zone PSA density with the PSA and PSA density in a group of patients in whom serum PSA values are between 4.0-10 ng/ml.

Between January 1998 and May 1999, 46 patients in whom digital rectal examination are normal and PSA values between 4.0-10 ng/ml, underwent systematical prostate biopsies following prostate and transitional zone volume measurements with transrectal ultrasound.

In 6 of 46 patients (13%) prostate cancer was found. In patients with BPH and prostate cancer, the average PSA density values were 0.11±0.05 and 0.17±0.08 ng/ml/cc respectively where the same measurements for the average transitional zone PSA density were 0.19±0.13 and 0.33±0.16 respectively (p<0.05). If the cut-off value of PSA density is taken as 0.15 ng/ml/cc 50% of the cancers are missed. The sensitivity and specifity of transitional zone PSA density of the cut-off value of 0.3 ng/ml/cc was found 66.7% and 90% respectively.

In patients with a PSA value 4.0 and 10 ng/ml, the transitional zone PSA density is more specific than PSA and PSA density. When supported with prospective studies in larger series, the transitional zone PSA density can be a useful in prostate cancer.