[Dose escalation with three dimensional conformal radiotherapy for prostate cancer: more is better?].

PURPOSE The present study was undertaken to determine the effect of radiation dose on biochemical control and morbidity in prostate cancer patients. MATERIALS AND METHODS Between 1995 and 2003, 360 patients with T1-T3b prostate cancer were treated in a sequential radiation dose escalation trial from 66.0 to 82.6 Gy. These patients were prospectively assigned to 1 of 3 prognostic groups according to risk factors: a) low risk patients were treated with 3DCRT alone; b) intermediate risk patients were allocated to receive neoadjuvant AD (NAD) 4-6 months prior and during 3DCRT; and c) high-risk received NAD and adjuvant AD (AAD) 2 years after 3DCRT. RTOG/EORTC toxicity score was used to analyze late complications RESULTS Median follow-up was 48 months (12-138). The actuarial biochemical disease free survival (bDFS) at 4 years for low risk, intermediate risk and high risk patients was 88%, 68% and 79% respectively. Stratified and multivariate analysis showed that higher radiation dose (>76 Gy) (p=0.0053) and the use of AAD for high risk patients (p=0.0046) correlated significantly with an improvement of bDFS for all patients. The incidence of late grade 2 rectal and urinary bleeding were 7% and 11% respectively. CONCLUSION The present study confirms an independent benefit of high-dose (> 76 Gy) radiation therapy and long-term AAD in high-risk prostate cancerpatients.