[Usefulness of free PSA/total PSA ratio in the diagnosis of prostatic cancer in symptomatic patients with PSA levels ranging from 2.5 to 20 ng/ml].
OBJECTIVE
To evaluate the value of free PSA/total PSA ratio (fPSA/tPSA) to boost total PSA (tPSA) specificity in the diagnosis of prostate cancer in a series of symptomatic patients.


METHODS
Prospective study on 334 patients presenting symptoms compatible with PBH and tPSA (ProStatus, Wallace Oy, Turku, Finland) between 2.5 and 20 ng/ml, and mean age 67.2 +/- 7 (49-87). Patients were divided into 3 groups: Group I (normal DRE and tPSA between 2.5 and 10 ng/ml)--189 patients. Group II (normal DRE and tPSA between 10 and 20 ng/ml)--78 patients. Group III (suspicion DRE and sPSA between 2.5 and 20 ng/ml)--67 patients. For each group, the sensitivity, specificity and ROC curves were calculated for several cut-off values of the lPSA/tPSA ratio.


RESULTS
Group I--Prostate cancer was diagnosed in 11% (20/189) patients. Significant differences were found only in the lPSA/tPSA ratio (p = 0.01). Using 27% as the cut-off value, cancer would have been diagnosed in 95% (19 of 20) patients, decreasing the total number of negative biopsies by 21% (39 of 189). Group II--Prostate cancer was diagnosed in 19% (15/78) patients. The only significant differences found were in prostate volume (p = 0.02). Using 30% as the cut-off value, 93% (14 of 15) patients with cancer would have been diagnosed, decreasing the total number of biopsies by 6.5% (5 of 78) and the number of negative biopsies by 8% (5 of 63). Group III--Prostate cancer was detected in 72% (48/67) patients. Significant differences were found in lPSA/tPSA ratio (p = 0.003), prostate volume (p = 0.02) and presence of ultrasound nodes (p = 0.004). Using 25% as the cut-off value, 96% (46 of 48) of patients with cancer would have been diagnosed, decreasing the total number of biopsies by 13% (9 of 67) and the number of negative biopsies by 47% (9 of 19).


CONCLUSIONS
We advise use of lPSA/tPSA ratio only in patients with normal DRE and tPSA between 2.5 and 10 ng/ml. Biopsing patients with lPSA percent equal to or lower than 27% would have prevented 23% of negative biopsies while still maintaining a diagnostic sensitivity of 95%.
Herranz Amo
F
F
Servicio de Urología, H.G.U. Gregorio Marañón, Madrid.
Verdú Tartajo
F
F
Díez Cordero
J M
JM
Leal Hernández
F
F
Bielsa Carrillo
A
A
García Burgos
J
J
Subirá Ríos
D
D
D000368:Aged; D000369:Aged, 80 and over; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D012680:Sensitivity and Specificity
D017430:Prostate-Specific Antigen