Survival Outcomes of Dose-Escalated External Beam Radiotherapy (DE-EBRT) Versus Combined Brachytherapy for Intermediate- and High-Risk Prostate Cancer Using the National Cancer Data Base.

PURPOSE - The purpose was to evaluate survival outcomes between dose-escalated external beam radiotherapy (DE-EBRT) versus EBRT plus brachytherapy for intermediate- and high-risk prostate cancer, using the National Cancer Data Base (NCDB).

MATERIALS AND METHODS - Patients with cN0M0 prostate cancer treated from 2004-2006. RT comparison groups were the following: EBRT alone (75. 6-81 Gy) and EBRT (40-50. 4 Gy) plus brachytherapy, with EBRT delivered in 1. 8-2. 0 Gy per fraction. Brachytherapy data was limited to yes/no, with no information on modality, dose or schedule. Eligible patients had known receipt of androgen deprivation therapy (ADT). Overall survival was evaluated using multivariate (MVA) Cox regression and propensity score-matched analyses.

RESULTS - A total of 20,279 patients with intermediate-risk (n=12,617) and high-risk (n=7,662) prostate cancer were included; 71.3% received EBRT alone, 28.7% received EBRT plus brachytherapy. Median follow up was 82 months (range, 3-120 months) and median age was 70 years (36-90 years). By MVA, EBRT plus brachytherapy was associated with improved survival (Hazard ratio [HR], 0.75; p<0.001) compared to EBRT alone (75.6-81 Gy); this significance remained consistent for both intermediate-risk (HR, 0.73; p<0.001) and high-risk (HR, 0.76; p<0.001) when analyzed separately. On subset analysis however, EBRT plus brachytherapy was not associated with improved (HR, 0.91; p=0.083) when compared to very high dose EBRT alone (79.2-81 Gy) for all patients combined.

CONCLUSIONS - We observed an association with the use of EBRT plus brachytherapy as compared to EBRT (75. 6-81 Gy) and a reduced risk of death in men with intermediate- and high-risk prostate cancer, but this association was no longer significant when EBRT doses of 79. 2-81 Gy are used.

The Journal of urology. 2015 Nov 11 [Epub ahead of print]

Arya Amini, Bernard Jones, Matthew W Jackson, Norman Yeh, Timothy V Waxweiler, Paul Maroni, Brian D Kavanagh, David Raben

Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. , Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. , Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. , Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. , Department of Surgery, Division of Urology, University of Colorado School of Medicine, Aurora, Colorado. , Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado. , Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.

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