Effect of adjuvant radiation therapy on prostate specific antigen following radical prostatectomy

A total of 21 patients received adjuvant radiation therapy after radical prostatectomy for a persistently detectable prostate specific antigen value (more than 0.6 ng. per ml.) postoperatively. Adjuvant radiation therapy decreased serum prostate specific antigen values to the undetectable range in 6 of 21 patients (29%) all of whom have remained free of tumor recurrence with a mean followup of 12.6 months (range 6 to 30). Three patients initially showed a decrease in serum prostate specific antigen to undetectable levels but they subsequently demonstrated an increasing level within 12 months after adjuvant radiation therapy. Additionally, 7 of 13 patients whose prostate specific antigen values remained in the detectable range despite adjuvant radiation therapy have had clinical evidence of tumor recurrence. Further followup will be required to determine what ultimate impact adjuvant radiation therapy will have on survival free of tumor.