Factors influencing the ratio of free to total prostate-specific antigen in serum

Abstract

The ratio of free prostate‐specific antigen (f‐PSA) to total PSA (t‐PSA) in serum, calculated as percent free PSA (f‐PSA%), is lower in patients with prostate carcinoma (PCa) than in patients with benign prostate hyperplasia (BPH). This parameter facilitates discrimination between the 2 groups of patients, but there is an overlapping of data. A better understanding of factors influencing this ratio is of practical importance. Therefore, f‐PSA% was measured in controls and patients suffering from BPH, PCa and chronic prostatic inflammation with t‐PSA concentrations up to 20 μg/l using the IMMULITE assays. The relationships of f‐PSA% to clinical situation, age, prostate volume, kind of treatment, and stage and grade of tumor were calculated. Compared with controls or BPH patients, mean f‐PSA% values were reduced in PCa patients and in patients with chronic prostatic inflammation. The prostate volume was the most important factor to influence f‐PSA%. The difference of f‐PSA% between PCa and BPH patients with prostate volumes smaller than 40 cm3 was lost if the prostate volumes exceeded 40 cm3. No relationship of f‐PSA% to pTNM stage or grade of tumor was observed. In contrast to t‐PSA concentrations, the f‐PSA% values were not age‐dependent and were not influenced by any kind of treatment in BPH and PCa patients either, which simplifies the use of f‐PSA% compared with t‐PSA. Thus, for using f‐PSA% in clinical practice and for interpreting the data correctly, the advantages shown have to be considered along with the potential limitations of f‐PSA%. Int. J. Cancer 74:630–636.© 1997 Wiley‐Liss, Inc.

Dietary intervention in prostate cancer patients: PSA response in a randomized double‐blind placebo‐controlled study

“…26,27 The use of the FT ratio within patients, e.g., to assess preoperatively the pathologic stage or monitor disease progression, is less well established. 28,29 In our study, no FT ratio treatment effect was found (data not shown).…”

The ratio of prostate‐specific antigen (PSA) to prostate volume (PSA density) as a parameter to improve the detection of prostate carcinoma in PSA values in the range of < 4 ng/mL

“…The interobserver and intraobserver variation of 13-15% did not differ from that found in earlier investigations. 35 All men underwent DRE. A DRE finding that was nonsuspicious for carcinoma was defined as negative, and a finding that was suspicious for carcinoma was considered positive.…”

Molecular Cloning of the Human Kallikrein 15 Gene (KLK15)

“…Small pieces of tissue were dissected immediately after removal of the prostate and stored in liquid nitrogen until analysis. Histological analysis from all the tissue pieces was performed as described previously (31) to ensure that the tissue was either malignant or benign. The tissues were pulverized with a hammer under liquid nitrogen, and RNA was extracted as described above, using Trizol reagent.…”