The Role of Free/Total PSA in the Differential Diagnosis of the Prostate Cancer and Benign Prostatic Hyperplasia

Hong, Bumsik; Ryu, Jin Sook; Ahn, Hanjong

Abstract

OBJECTIVES
This study examined the role of free/total prostate specific antigen (PSA) in the differentiation between prostate cancer and benign prostatic hyperplasia (BPH) in patients with total PSA higher than 4.0 ng/ml.
MATERIALS AND METHODS
Fourteen untreated patients with prostate Cancer and 63 patients with BPH were included in this study. All patients were pathologically diagnosed by sextant transrectal biopsy before treatment. The level of total PSA and free PSA were determined by immunoradiometric assay (Cis bio international). The median values of total PSA and F/T (free/ total PSA) were compared between prostate cancer and BPH in the three different ranges of total PSA (PSA>4.0ng/ml, 4.0 ng/ml Characteristic (ROC) curves were obtained using sensitivity and specificity of total PSA and F/T at each cutoff level.
RESULTS
In the range of PSA between 4.0 and 10.0 ng/ml, the median value of F/T was significantly different between prostate cancer and BPH (p<0.05), while that of total PSA was not. In other ranges of PSA, both total PSA and F/T were significantly different between prostate cancer and BPH. The area under the F/T ROC curve was significantly larger than that of total PSA ROC curve only in the range of PSA between 4.0 and 10.0 ng/ml.. In the mean time, F/T was more specific than total PSA (52% vs 32%) at the identical sensitivity (93%) of F/T and total PSA cutoff values (F/T cutoff, 0.2; total PSA cutoff, 6.0 ng/ml).
CONCLUSIONS
Free/Total PSA might provide us more reliable information on the differential diagnosis of the prostate cancer, especially in patients with PSA range between 4.0 and 10.0 ng/ml.