Radiotherapy for regionally localized hormone refractory prostate cancer

Abstract

Patients with regionally localized hormone refractory adenocarcinoma of the prostate are often referred for radiotherapy to relieve local symptoms, prevent further local progression, or prevent impending urinary tract obstruction. However, the merits of radiotherapy for this patient population have not been documented. In this retrospective series, the results of 29 such patients treated at our institution between 1987-1992 are reviewed. Prior to androgen ablation, the majority of these patients (79%) had Stage D0 or D1 disease. After androgen ablation, radiotherapy was given to 16 (55%) for progressive symptoms (mostly urinary obstructive), 11 (38%) for palpable local progression in the absence of symptoms, and 2 for a rising prostate specific antigen (PSA) profile without palpable disease. None of the patients had distant metastasis at the time of radiotherapy. The median dose to the prostate was 66 Gy and the median follow-up after radiotherapy was 43 months. Following local-regional radiotherapy, the actuarial rate of local failure at 4 years was only 39%. However, 80% had disease progression or a rising PSA in this time period. The actuarial survival at 4 years following radiotherapy was 39%. Univariate analyses of potential prognostic factors revealed that preandrogen ablation Gleason score, preradiotherapy PSA, and preradiotherapy prostatic acid phosphatase (PAP) were predictive of patient outcome. Most importantly, doses above 60 Gy to the prostate at standard fractionation were associated with symptom-free local control in 90% of patients at 3 years. The majority of the patients were treated using limited fields (n = 20). The regionally localized hormone refractory prostate cancer patients described benefited from high dose, continuous course, local radiotherapy in that excellent local control rates were obtained for an extended period. Because the majority of these patients fail with distant metastasis within 4 years, this treatment represents an aggressive approach to palliation that is justified by the maintenance of freedom from local symptoms.