Serum prostate-specific antigen after post-prostatectomy radiotherapy.

External beam radiotherapy was administered to 39 patients after radical prostatectomy for adenocarcinoma. Thirty-seven of 39 patients had detectable levels of serum prostate-specific antigen (PSA) prior to irradiation as evidence of residual carcinoma (biochemical evidence of disease). Two patients also had palpable recurrences. Pathologic analysis of the surgical specimens suggested that positive surgical margins, seminal vesicle or lymph node involvement, or high Gleason pattern scores are associated with measurable PSA after surgery. Follow-up ranged from two to seventy-four months (mean 26.8 months). To date, local control has been achieved in all but 1 patient (including 2 patients with palpable tumor prior to radiotherapy). Two distinct risk groups for the development of distant metastases based on the trend of the PSA in relation to the duration of follow-up after radiotherapy are defined. In the high-risk group (those patients with a rising PSA), in 9 of the 18 bone metastases have developed, while none of the 17 low-risk patients have metastatic disease.