FREE TO TOTAL PROSTATIC SPECIFIC ANTIGEN RATIO AS A NEW DIAGNOSTIC-TOOL IN PROSTATIC-CARCINOMA

One hundred seventy-one patients with clinical suspicion of prostate c ancer were initially selected and underwent total and free PSA determi nation digital rectal examination and transrectal ultrasonography. Six ty-five had total PSA values between 4 to 20 ng/ml. In these patients in addition to the free to total PSA ratio, the sensivity, specificity , positive predictive value, true and false negative predictive value were evaluated comparing these findings with histopathological charact erization. Receiver Operating Characteristic Analysis was also perform ed No statistically significant differences were evidenced between ben ign and neoplastic prostates comparing total PSA values, while signifi cant differences were found by comparing both free PSA and the free to total PSA ratio (p < 0.01). Our experience demonstrates that using a 0.20 free to total PSA ratio cut-off, it is possible avoid 44.4% of fo llowing clinical tests, and biopsies could be saved in almost 40% of p atients with a considerable cost-benefit ratio.