Role of Postradical Prostatectomy Irradiation in Carcinoma of the Prostate.

Abstract

The indications and results of postradical prostatectomy adjuvant pelvic radiation therapy (6,000 to 6,500 cGy) are reviewed. In patients with positive with positive surgical margins, 80% to 100% local tumor control has been reported; in 42 patients treated at our institution, the 5-year actuarial tumor control rate was 85%. Most authors report higher disease-free survival (DFS) rates in patients receiving adjuvant postoperative irradiation for positive margins (70% to 80% at 5 years and 50% to 70% at 10 years) compared with nonirradiated patients (50% at 5 years and 40% at 10 years). However, more difficult to document and never indisputably reported has been the improvement in overall survival (OS) rates with adjuvant irradiation; the actuarial survival rates, 75% to 80% at 5 years and 45% to 60% at 10 years, are comparable to those of nonirradiated patients. Results have been published on patients with positive pelvic lymph nodes (stage D1) following pelvic irradiation (6,000 to 6,500 cGy). At our institution, the 5-year DFS rates were 60% in 22 patients without extracapsular tumor extension and 20% in 34 patients with perprostatic involvement. In 24 patients with postprostatectomy persistently or subsequently elevated prostatic specific antigen (PSA) levels, preliminary analysis showed initial 79% decrease in PSA level after pelvic irradiation (6,000 to 6,500 cGy), although only 70% of the patients have sustained such decreased levels. Patients with persistent or subsequent elevation of PSA after irradiation have a high incidence of distant metastases (50%). There is a suggestion that patients with elevated PSA levels treated to the pelvic lymph nodes (4,500 to 5,000 cGy), in addition to a boost to the prostatic bed (to a total dose of 6,500 cGy), have better results than patients treated to the prostatic bed only. However, longer follow-up is necessary to definitely ascertain the value of irradiation in these patients. Patients with postprostatectomy isolated, clincally palpable recurrences, when treated with irradiation (to 6,500 cGy), have a high probability of local tumor control (90% in 23 patients) at our institution. There is a suggestion that irradiation of the pelvic lymph nodes, in addition to the prostatic recurrence, yields better results. Unfortunately, approximately 60% of these patients develop distant metastases and have poor rates of survival. In conclusion, adjuvant irradiation plays a major role in patients treated with radical prostatectomy in various clinical situations. Radiation therapy as described is well-tolerated. Additional prospective randomized studies are necessary to better assess the role of irradiation in the treatment of these patients.