Effect of Radiation Therapy on Detectable Serum Prostate Specific Antigen Levels Following Radical Prostatectomy: Early Versus Delayed Treatment

Radiation therapy may be beneficial after radical prostatectomy in some patients with pathological stage C prostate cancer and in those with detectable postoperative prostate specific antigen (PSA) levels. A total of 64 men underwent postoperative radiation therapy following radical prostatectomy for pathological stage C disease (27), a detectable serum PSA level (11) or both conditions (26). Of the 27 men treated prophylactically for pathological stage C disease 18 (67%) had no evidence of recurrence after radiation within the first 6 months postoperatively (median followup 40 months, range 17 to 97). Of 22 men treated for delayed PSA elevation 15 (68%) currently are disease-free (median followup 27.5 months, range 15 to 47). Of 15 men treated within the first 6 months after radical prostatectomy for persistently detectable PSA levels 8 (53%) had an initial decrease in PSA to undetectable levels but only 5 (33%) had a durable complete response (median followup 36 months, range 8 to 56). We conclude that patients with pathological stage C disease who are most likely to benefit from postoperative radiation therapy are those with initially undetectable postoperative PSA levels. We observed no striking difference in treatment outcome between early and delayed adjuvant radiation therapy.