[Free/total prostate specific antigen ratio (%PSA) to predict probability of prostate cancer].

It has been reported recently that %PSA, the ratio of free-PSA(F-PSA) and total-PSA(T-PSA), remains significantly lower in sera of patients with prostatic cancer(PCA) than there in cases with benign prostate hypertrophy(BPH). We examined %PSA can be used for differential diagnosis of PCA from BPH. Forty-seven non-treated Japanese patients with prostate problem were examined for PSA assays and biopsy. On biopsy, 25 cases were diagnosed as PCA, and 22 cases as BPH. On T-PSA value, there were 18 cases of PCA and 8 cases of BPH whose T-PSA values were over 10 ng/ml. When %PSA was studied, cases with less than 15% of %PSA were found to be PCA exclusively(16/16), while cases with less than 20 of %PSA included 19 PCAs and 4 BPHs. In 17 PCA patients with stage B to stage D, the %PSA was less than 20 except one case. T-PSA was examined in 88 cases at the checkup in our old age home. Four samples of which T-PAS levels were in gray zone, were assayed for %PSA. Two of them, with %PSA values less than 20 ng/ml, were found to be PCA, while the remaining two, with %PSA over 20 ng/ml, were BPH.