Preliminary report on 10 patients treated with radiotherapy after radical prostatectomy for isolated elevation of serum PSA levels

Since 1987, 10 patients have been treated with irradiation to a limited pelvic volume for elevation of serum prostate-specific antigen (PSA) level above expected post-radical prostatectomy levels without clinical or radiological evidence of either metastatic or locoregional disease. The patients were treated 3 to 43 months after radical prostatectomy, using bilateral 120° arcs to deliver 6000 cGy to the prostatic bed. The pathologic findings of the initial surgical specimens for all patients were reviewed. Eight patients had pathologic Stage C disease, and five patients had one or more positive margins. All patients had negative staging lymphadenectomies. After irradiation, eight patients had decreases in PSA levels indicative of response of isolated local disease. Though preliminary, these results suggest that post- prostatectomy PSA levels are useful for detecting subclinical local recurrence or persistence in the prostatic bed, as well as monitoring these patients' response to therapy. The value of this elective treatment remains to be documented.