Conventional external-beam radiation therapy alone or with androgen ablation for clinical stage III (T3, NX/N0, M0) adenocarcinoma of the prostate

Purpose: To evaluate the outcome of clinical Stage III (T3, N0/NX, MO) pros tate cancer treated by conventional radiation alone or with adjuvant androg en ablation, Methods and Materials: Three hundred forty-four men with T3, N0/NX, MO aden ocarcinoma of the prostate who received conventional radiation alone (260) or with androgen ablation (84) were analyzed for relapse or rising prostate -specific antigen (PSA), using univariate and multivariate techniques. Results: With a median follow-up of 68 months, the 260 men treated with rad iation alone had a 10-year actuarial rate of relapse or rising PSA of 76%, Pretreatment PSA level (less than or equal to 10 ng/ml vs. > 10 less than o r equal to 20 ng/ml vs. > 20 ng/ml) and radiation dose (< 68 Gy vs. greater than or equal to 68 Gy) were the only independently significant determinan ts of biochemical failure; Gleason score (2-7 vs. 8-10) was an additional d eterminant of metastatic relapse. Patients treated to doses < 68 Gy experie nced 6-year failure rates exceeding 50% regardless of PSA level. Patients w ith PSA less than or equal to 10 ng/ml and receiving 68-70 Gy had a 6-year failure of 24%, but those with PSA > 10 ng/ml had relapse rates exceeding 5 0% even at doses of 70 Gy, At a median follow-up of 44 months, the 84 patie nts treated with radiation and androgen ablation had a 6-year biochemical f ailure rate of 22%. The only significant determinant of outcome in this gro up was pretreatment PSA; patients with PSA less than or equal to 80 ng/ml h ad a 6-year failure rate of only 12% compared to a failure rate of 53% for those with PSA > 80 ng/ml, The outcome for those treated with combined moda lities was significantly better than for those treated with radiation alone in all PSA strata, Conclusion: Conventional radiation alone has little curative potential for Stage III disease. Doses < 68 Gy are particularly ineffective. Patients wit h PSA less than or equal to 10 ng/ml may be candidates for conventional rad iation to a dose of 70 Gy, Other patients are probably best served by combi ned radiation-androgen ablation or high-dose conformal radiation. (C) 1999 Elsevier Science Inc.