Limited suppression of prostate-specific antigen after salvage radiotherapy for its isolated elevation after radical prostatectomy

Objectives, To investigate the clinical outcome and degree of prostate-spec ific antigen (PSA) suppression after salvage radiotherapy performed because of isolated PSA elevation after radical prostatectomy. Methods. We examined the outcomes of 32 patients who underwent radiotherapy after radical prostatectomy. Hypersensitive, as well as conventional, PSA assays were used to measure PSA levels after irradiation. Results. Of 125 patients who underwent radical prostatectomy for clinically resectable prostate cancer, 42 (35.6%) developed detectable PSA an average of 13.5 months postoperatively, Thirty-two patients underwent salvage radi otherapy. In 13 patients (40.6%), PSA became undetectable (less than 0.1 ng /mL) at a mean of 1.2 months. Two of these patients later developed detecta ble PSA within 12 months. Of 22 patients who had at least 12 months of foll ow-up, 8 had a durable PSA response. Of 13 patients who attained an undetec table PSA postoperatively and then showed a delayed progressive increase, 7 exhibited a durable response lasting for more than the 12 months after irr adiation. By contrast, only 1 of 9 patients with persistently elevated post operative PSA showed undetectable levels after irradiation. Frozen sera fro m the 8 patients with a durable response to irradiation were available to m easure levels less than 0.1 ng/mL by hypersensitive assay. The mean value w as 0.035 ng/mL at an average of 26.9 months after irradiation. Only 3 patie nts had levels less than 0.01 ng/mL. Conclusions, Although radiotherapy may be beneficial in a small number of p atients, many patients continue to have measurable levels of PSA (more than 0.01 ng/mL) after irradiation. Our results suggest that this treatment in its current form is inadequate to eradicate residual carcinoma. UROLOGY 53: 148-154, 1999. (C) 1999, Elsevier Science Inc. All rights reserved.