DEFINITIVE EXTERNAL IRRADIATION IN STAGES-A (T1) AND STAGES-B (T2) CARCINOMA OF THE PROSTATE

This is a retrospective review of records of 38 patients with clinical stage A (T1a,b), 131 with stage B1 (T2a), and 113 with B2 (T2b) histo logically proven adenocarcinoma of the prostate treated with definitiv e irradiation. All patients have been followed for a minimum of 3 year s (median follow-up: 6.5 years; maximum: 23 years). Patients were trea ted with high-energy photons (18-22 MV) with either 4,500 cGy to pelvi c fields and a boost of about 2,000 cGy to the prostate or 6,600 cGy t o the prostate and periprostatic tissues. Five patients with stage A1 (T1a) tumors had no failures. The local recurrence rate was 11% in sta ge T1b, 14% in T2a, and 17% in T2b tumors. Distant metastasis rates we re 16% in patients with stage T1b, 20% in T2a, and 21% in T2b. The dis ease-free survival rate was approximately 70% at 5 years and 55% at 10 years in patients with stages T1b or T2, without significant differen ce among the various groups. The cause-specific survival was 90% at 5 years and 70% at 10 years in the various groups. The results are compa rable to those reported in several surgical or radiation therapy serie s at various institutions. A significantly lower disease-free survival was observed in patients with poorly differentiated tumors (40% at 5 years) in comparison with those with well- and moderately differentiat ed tumors (80% DFS at 5 years) (p < .001). Likewise, the cause-specifi c survival was lower in patients with poorly differentiated tumors (75 % at 5 years) than in the other patients (91%) (p = .0003). No differe nce in the local recurrence rates with various degrees of differentiat ion was noted. However, patients with poorly differentiated tumors had a greater incidence of distant metastasis (30%-40%) than patients wit h well or moderately differentiated lesions (10%-20%). Performance of transurethral resection also was associated with a higher incidence of distant metastasis (40%) in patients with stage B2 (T2b) tumors than in those diagnosed by needle biopsy (20%) (p = .12) but not in the oth er groups. Age, race, volume irradiated, or doses of irradiation lower or higher than 6500 cGy did not significantly affect outcome. Radiati on therapy is an effective treatment for patients with stage A (T1) or B (T2) carcinoma of the prostate. Careful selection and refinement of treatment techniques, including three-dimensional treatment planning and conformal delivery irradiation or brachytherapy, may improve the m anagement of these patients.