Long-term results after high-dose radiotherapy and adjuvant hormones in prostate cancer: how curable is high-risk disease?

Abstract

To analyze long-term outcome and prognostic factors for high-risk prostate cancer defined by National Comprehensive Cancer Network criteria treated with high-dose radiotherapy and androgen deprivation in a single institution. A total of 306 patients treated between 1995 and 2007 in a radiation dose-escalation program fulfilled the National Comprehensive Cancer Network high-risk criteria. Median International Commission on Radiation Units and Measurements radiation dose was 78 Gy (range, 66.0-84.1 Gy). Long-term androgen deprivation (LTAD) was administered in 231 patients, short-term androgen deprivation (STAD) in 59 patients, and no hormones in 16 patients. The Phoenix (nadir plus 2 ng/mL) consensus definition was used for biochemical control. Multivariate analysis was performed to determine the independent prognostic impact of clinical and treatment factors. Median follow-up time was 64 months (range, 24-171 months). The actuarial overall survival at 5 and 10 years was 95.7% and 89.8%, respectively, and the corresponding biochemical disease-free survival (bDFS) was 89.5% and 67.2%, respectively. Fourteen patients (4.6%) developed distant metastasis. Multivariate analysis showed that Gleason score>7 (p=0.001), pretreatment prostate-specific antigen (PSA) level>20 ng/mL (p=0.037), higher radiation dose (p=0.005), and the use of adjuvant LTAD vs. STAD (p=0.011) were independent prognostic factors affecting bDFS in high-risk disease. The 5-year bDFS for patients treated with LTAD plus radiotherapy dose>78 Gy was 97%. For high-risk patients the present series showed that the use of LTAD in conjunction with higher doses (>78 Gy) of radiotherapy was associated with improved biochemical tumor control. We observed that the presence of Gleason sum>7 and pretreatment PSA level>20 ng/mL in the same patient represents a 6.8 times higher risk of PSA failure. These men could be considered for clinical trials with addition of novel agents.