The role of free prostate-specific antigen in the diagnosis of prostate cancer

OBJECTIVE: To determine whether the free/total prostate-specific antigen (PSA) ratio can discriminate between patients with prostate cancer or benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: A prospective study was conducted using free and total PSA assays in patients who underwent transrectal-ultrasound guided biopsies indicated by a total serum PSA level of > 4 ng/mL and/or a positive digital rectal examination. Sixty-nine men (median age 68 years, range 57-86) who presented to our out-patient department with symptoms of prostatism were included in the study. Blood samples were drawn from all patients before biopsy. RESULTS: Histopathological examination detected prostate cancer in 17 of 69 (25%) patients and 13 of these 17 patients had a free/total PSA ratio of or = 0.15 were 71%, 76%, 38%, 93%, respectively. CONCLUSION: These results indicate that using the free/total PSA ratio gives a significant improvement over PSAD and total PSA values alone in the diagnosis of prostate cancer: its use may also enhance the diagnostic accuracy in patients with intermediate PSA levels