The free-to-total serum prostatic specific antigen ratio as a predictor ofthe pathological features of prostate cancer

Objectives To analyse the role of the ratio of serum free (f) to total (t) prostatic specific antigen (f/tPSA) as a predictor of the pathological feat ures in patients with clinical stage Tie disease submitted for radical pros tatectomy. Patients and methods Total and fPSA were determined before surgery in 76 co nsecutive patients with clinical stage T1cNOMO disease and a serum tPSA lev el of 4-20 ng/mL. The pathological stage was defined as organ-confined in 4 7 (62%), with capsular penetration in 27 (35%) and seminal Vesicle infiltra tion in two (3%). In 18 of the specimens (24%) the surgical margins were po sitive, The pathology was favourable in 41 patients (55%), Total and fPSA w ere determined using the Tandem and Tandem-free PSA immunoassays (Hybritech Inc, Belgium) Results The mean tPSA was: 8.7 ng/mL when the tumour was organ-confined and 8.6 ng/mL, when the disease was extraprostatic (P > 0.05); 8.4 ng/mL when the tumour was specimen-confined and 9.3 ng/mL when positive margins or sem inal vesicle involvement were detected (P > 0.05); and 8.3 ng/mL when the p athology was favourable and 9.0 ng/mL, when unfavourable (P > 0.05). The f/ tPSA was 11.8% when the tumour was organ-confined and 9.1% when it was not (P < 0.03), 11.9% when the tumour was specimen-confined and 7.6% when not ( P < 0.002) and 12.1% when the pathology was favourable and 9.1% when unfavo urable (P < 0.008). A threshold of 11% f/tPSA provided an odds ratio for or gan-confined disease of 2.7, for specimen-confined disease of 7.6 and for a favourable pathology of 3.9. Conclusion The f/tPSA seems to provide useful information in the prediction of the pathological features of patients with clinical Tie prostate cancer and a tPSA of 4.1-20 ng/mL.