Association of free PSA percent, total PSA, age, and gland volume in the detection of prostate cancer

✍ Scribed by Mettlin, Curtis; Chesley, Arthur E.; Murphy, Gerald P.; Bartsch, Georg; Toi, Ants; Bahnson, Robert; Church, Paul

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 177 KB
• Volume: 39
• Category: Article
• ISSN: 0270-4137
• DOI: 10.1002/(sici)1097-0045(19990515)39:3<153::aid-pros2>3.0.co;2-v

✦ Synopsis

Background:

Measurement of the free fraction of total prostate-specific antigen (fpsa%) has been proposed as a useful addition to total psa for the detection of prostate cancer.

Methods:

We assessed the performance of fpsa% in differentiating men with prostate cancer from men without cancer in a group of 1,709 subjects studied in five institutions.

Results:

On the basis of psa testing, digital rectal examination, and ultrasound examination conducted at one or more visits, 229 cancers were diagnosed. the mean fpsa% in men with cancer was 9.1% compared to 18.9% in men without cancer. the fpsa% varied by age, with men under 60 having a mean fpsa of 13.9% compared to 17.5% in men 60-69 years old and 19.8% in men over age 70. significant associations of fpsa% with gland volume and psa level were also observed. the sensitivity, specificity, and positive predictive value of different fpsa% cutoff levels were assessed in 513 men who underwent sextant biopsy. sensitivity of 85.4%, 32.1% specificity, and a 39.2% positive predictive value were observed using an fpsa cutoff of 15% in men with psa in the 4.0-9.9 ng/ml range. sensitivity of 96.9%, 12.3% specificity, and a 36.2% positive predictive value were observed using an fpsa cutoff of 20% in the same men. if 15% fpsa had been used as a biopsy criterion in men with psa of 4.0-9.9 ng/ml, the number of biopsies performed could have been reduced by 21.2%, with a concomitant reduction in cancer detection of 14.6%. using a 20% fpsa criterion, biopsies would have been reduced 12.7%, with a 3.1% reduction in cancer detection.

Conclusions:

These results provide some evidence that the detection of prostate cancer is enhanced by measuring fpsa% in addition to the established measure of total psa level. further research is needed to identify other markers that have better sensitivity and specificity.