Adjuvant radiation therapy in patients with detectable prostate specific antigen following radical prostatectomy

Adjuvant radiation therapy following radical prostatectomy for adenocarcinoma of the prostate was given to 25 patients. Of these patients 8 had microscopic lymph node metastasis, 8 had seminal vesicle invasion without positive lymph nodes, 6 had positive surgical margins and 3 had only capsule penetration. Their only evidence of residual disease was detectable serum prostate specific antigen (PSA) by the Yang assay. A total of 15 patients (60%) had a subsequent decrease in PSA to less than 0.3 ng./ml. and an additional 5 (20%) had a decrease in PSA by more than 50%. Currently 8 patients have no detectable PSA after a median followup of 18 months (17 to 38 months) since initiating radiation therapy. Only 1 of 12 patients with detectable PSA immediately after radical prostatectomy has had a durable response to adjuvant radiation therapy. In contrast 7 of 13 patients with a delayed increase in PSA had a durable response. The ability of adjuvant radiation therapy to eliminate serum PSA in patients with a delayed increase in PSA after radical prostatectomy is encouraging. However, longer followup, including the use of nonradiated control subjects, is needed to assess the ability of adjuvant radiation therapy to control local disease and prolong patient survival.