[Serum prostate-specific antigen in a urological outpatient clinic. Efficacy of age-specific and prostate volume-specific reference range in detection of prostate cancer].
BACKGROUND
Prostate specific antigen (PSA) is the most available marker for early detection of prostate cancer. Nevertheless, the standard upper range of PSA (4.0 ng/ml) does not demonstrate sufficient specificity. Thus, we evaluated the distribution of PSA by age and prostate volume in urological patients, and determined PSA reference ranges by the each parameter. Diagnostic efficacy was also evaluated.


METHODS
Three-hundred-seventy-five patients who visited the urological outpatient clinic between January, 1994 and February, 1996, and were considered not to have prostate cancer, were analyzed PSA levels by age. Among them, two-hundred-seventy-six patients in whom prostate volumes were presumed by means of transabdominal ultrasonography, were evaluated a correlation of PSA values with prostate volumes. Using the age-specific and volume-specific reference ranges determined by this analysis, sensitivity, specificity, and positive predictive value were compared with those in case using the 0.0 to 4.0 ng/ml reference range and the 0.0 to 11.7 ng/ml reference range, in 72 patients (cancer 24, noncancer 48) in whom histological examinations were performed in the same period.


RESULTS
We found statistically significant slight correlations among age, prostate volume, and PSA. By using the age-specific reference range, volume-specific reference range, and 0.0 to 11.7 ng/ml reference range, we could elevate the specificity and positive predictive value approximately by 65% and 35%, respectively, compared with those of the 0.0 to 4.0 ng/ml reference range.


CONCLUSIONS
In order to decrease the number of rather invasive than necessary prostate biopsies, age-specific and volume-specific reference ranges are useful in urological outpatient clinic.
Takahashi
C
C
Miyagawa
I
I
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012016:Reference Values; D012680:Sensitivity and Specificity
D017430:Prostate-Specific Antigen