Analysis of the Cancer of the Prostate Risk Assessment to predict for biochemical failure after external beam radiotherapy or prostate seed brachytherapy - Abstract

OBJECTIVE: To analyze the value of the Cancer of the Prostate Risk Assessment (CAPRA) score to predict biochemical failure (bF) in patients with D'Amico low- or intermediate-risk prostate cancer treated with different radiation techniques.

METHODS: We analyzed 744 patients treated with either external beam radiotherapy (52.7%) or permanent-seed prostate brachytherapy (47.3%) without any androgen deprivation. External beam radiotherapy dose levels were extreme hypofractionation (45 Gy in 9 fractions) in 10%, 76-79.2 Gy (in 1.8-2.0 Gy per fraction) in 32.7%, and 70.2-74 Gy in 10%. All patients had a minimum of 36-month follow-up. Cox regression analysis was used for univariate and multivariate analysis to predict for bF, as per the Phoenix definition (prostate-specific antigen-nadir + 2 ng/mL).

RESULTS: Median follow-up for patients without bF was 56 months (range, 36-114 months). In univariate analysis, CAPRA score as a continuous variable was predictive of bF (hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.23-1.79; P < .001), and in multivariate analysis adjusted for treatment type, the HR was 1.39 (95% CI, 1.14-1.71; P = .002). D'Amico intermediate-risk vs low-risk patients had an HR for bF of 1.93 (95% CI, 1.07-3.47; P = .029) in univariate analysis, but the difference was not statistically significant anymore after adjustment for treatment type, (P = .206). The area under the curve of the CAPRA score as a continuous variable at 3 and 5 years was 0.66 and 0.62, respectively (P = .005 for both years).

CONCLUSION: The CAPRA score is predictive of bF. Each 1-point rise increased the risk of bF by 39%, which is comparable to surgical series.

Written by:
Delouya G, Krishnan V, Bahary JP, Larrivée S, Taussky D.   Are you the author?
Department of Radiation Oncology, Hôpital Notre-Dame, Center Hospitalier de l'Université de Montréal (CHUM), Montreal, Canada; University of Montreal Hospital Research Centre, Montreal, Canada.  

Reference: Urology. 2014 Sep;84(3):629-33.
doi: 10.1016/j.urology.2014.05.032

PubMed Abstract
PMID: 25168545 Prostate Cancer Section