External beam radiation monotherapy for prostate cancer

Background: To clarify the implications and limitations of external beam ra diation monotherapy for localized prostate cancer, the long-term outcomes a nd prognostic factors were investigated. Methods: Between 1976 and 1994, 91 patients with untreated prostate cancer were treated with external beam radiation therapy alone. Thirty-two were cl assified as T1b, eight were T2a, four were T2b and 47 were T3. Pelvic lymph adenectomy was carried out in 69 cases; 57 were staged as pN0, eight were p N1, four were pN2 and 22 were pNX. Linac X-rays were used in 55 cases, fast neutron in 15 and a combination of the two in 21. No other therapy was giv en until relapse and when relapse was evident endocrine therapy was started . Results: The observation period ranged from 3 to 206 months with a median o f 78 months. Local control rate and disease-free, cause-specific and overal l survivals at 10 years were 74.0, 49.6, 74.2 and 39.2%, respectively. By u nivariate analysis, T category, pN category and histologic grade were signi ficant prognostic indicators for disease-free survival. Multivariate analys is revealed that T category was an independent prognostic factor. In T2b an d T3 diseases, pN0/1 patients demonstrated significantly better disease-fre e survival than pNX. Conclusions: A favorable long-term outcome was achieved by external beam ra diation monotherapy in patients with minimally extended prostate cancer (T1 b and T2a). For locally advanced disease (T2b and T3), staging pelvic lymph adenectomy would be useful for the selection of patients.