Measurements of free and total PSA, tissue polypeptide-specific antigen (TPS), and CYFRA 21-1 in prostate cancer patients under intermittent androgen suppression therapy
✍ Scribed by Theyer, Gerhard; D�rer, Alexander; Theyer, Ulrike; Haberl, Ines; Ulsperger, Ernst; Baumgartner, Gerhard; Hamilton, Gerhard
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 194 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0270-4137
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✦ Synopsis
BACKGROUND. The present study evaluated monthly measurements of free and total prostate-specific antigen (PSA), and the tumor proliferation markers tissue polypeptide-specific antigen (TPS) and cytokeratin fragment 21-1 (CYFRA 21-1) in patients with advanced prostate cancer receiving intermittent androgen suppression therapy (IAS). METHODS. Thirty-four men received alternating cycles of 8 month androgen suppression and treatment cessation (mean duration, 10.3 months) until PSA increased to >20 g/l. Measurements of testosterone, percentage of free PSA, TPS, and CYFRA 21-1 were performed using ELISA and RIA assays. RESULTS. Periods of androgen suppression resulted in reversible reductions of testosterone (from 6 ± 0.8 to <0.58 ng/ml), PSA (from 31.2 ± 4.5 to <1.7 g/l), and prostatic volume (mean reduction, 22.2 ± 4.6%), indicating apoptotic regression of the tumors. Upon treatment cessation, testosterone increased to 6.1 ± 0.56 ng/ml within 2 months, followed by an increase of PSA to 5.8 ± 0.8 g/l. The mean percentage of free PSA (15.1 ± 2.6%) exhibited no significant change during the whole IAS cycle. TPS showed a decrease of 50% after 3 months, and CYFRA 21-1 a 25% decrease after 7 months of androgen suppression treatment. During treatment cessation, TPS exceeded the normal cutoff value of 90 U/l late in tumor regrowth (9-11 months), whereas CYFRA 21-1 remained below the normal cutoff value of 3.3 ng/ml. CONCLUSIONS. PSA is the best and most sensitive marker of prostate cancer regression and regrowth during IAS cycles of the markers tested in this study. Free PSA constitutes approximately 15% of total PSA (range, 5-32%), and its percentage showed no significant change during IAS cycles. The TPS and CYFRA 21-1 proliferation marker changes in IAS seem to be related mainly to effects on normal androgen-dependent tissues.