ADJUVANT RADIOTHERAPY FOR PATHOLOGICAL STAGE T3 4 ADENOCARCINOMA OF THE PROSTATE - 10-YEAR UPDATE/

Purpose: To determine the role of adjuvant postoperative radiotherapy (RT) following radical prostatectomy (RP) in a group of patients with pathologic Stage T3/4 adenocarcinoma of the prostate followed for a me dian of 10 years after treatment. Methods and Materials: Between 1970 and 1983, 159 patients underwent RP for newly diagnosed adenocarcinoma of the prostate and were found to have pathologic Stage T3/4 tumors. Forty-six received adjuvant RT and 113 did not. Radiotherapy usually c onsisted of 45-50 Gy to the whole pelvis followed by a boost to the pr ostate bed of 10-15 Gy, to a total dose of 55-65 Gy. Patients were ana lyzed with respect to survival, disease-free survival, local control, and freedom from distant metastases. A rising prostate-specific antige n in the absence of other evidence of relapse was scored as a separate category of recurrence. Results: Both groups of patients have been fo llowed for a median of 10 years. The actuarial survival at 10 and 15 y ears was 62% and 62% for the RT group compared to 52% and 37%, respect ively, for the RP group (p = 0.18). The disease-free survival for the RT group was 55% and 48% at 10 and 15 years, respectively, compared to 37% and 33% for the RP group (p = 0.16). Similarly, there was no diff erence in the rate of distant metastases between the two groups. Tn co ntrast, the local relapse rate was significantly reduced by the additi on of postoperative radiotherapy. The actuarial local control rate at 10 and 15 years was 92% and 82%, respectively, for the RT group vs. 60 % and 53% for the RP group (p = 0.002). Conclusions: While postoperati ve pelvic RT significantly improves local control compared to RP alone for pathologic Stage T3/4 prostate cancer, it has no impact on distan t metastases and consequently does not improve survival. These data ar e consistent with the conclusion that many patients with pathologic St age T3/4 prostate cancer have occult metastases at presentation and wi ll not be cured by local therapies alone. The optimal treatment for th is patient population remains to be established.