Prospective evaluation of prostate cancer detection by prostate specific antigen related parameters: comparison in...

We compared the usefulness of serum and plasma samples for enhancing the specificity of prostate cancer detection.

We analyzed receiver operating characteristics curves to evaluate prospectively the cancer detection performance of prostate specific antigen (PSA) related parameters derived from serum and plasma samples in 248 and 249 consecutive patients, respectively.

Receiver operating characteristics curve analysis showed that PSA density and transition zone PSA density were more powerful predictors of prostate cancer than total or free PSA in the group overall at intermediate serum PSA 2.1 to 10 ng./ml. and in the subgroup with total PSA 4.1 to 10 ng./ml. regardless of digital rectal examination findings. Percent free PSA performed significantly better than total PSA in patients with serum total PSA 4.1 to 10 ng./ml. PSA density, transition zone PSA density and percent free PSA did not differ substantially in patients with serum total PSA 4.1 to 10 ng./ml. However, none of these parameters distinguished patients with prostate cancer from those with benign histology when PSA was in the lower range of 2.1 to 4 ng./ml. The performance of these parameters was worse when plasma sample data were used for calculation.

The performance of percent free PSA appears at least comparable to that of PSA density and transition zone PSA density in patients in this cohort with serum total PSA 4.1 to 10 ng./ml. without regard to digital rectal examination. The poor performance of these parameters in the lower PSA range underscores the need for other parameters to improve the specificity of cancer detection in elderly Japanese males. Continued use of serum samples is justified for measuring PSA related parameters by current assay techniques.