Long-term outcomes from dose-escalated image-guided intensity-modulated radiotherapy with androgen deprivation: Encouraging results for intermediate- and high-risk prostate cancer - Abstract

PURPOSE: Dose-escalated (DE) radiotherapy in the setting of localized prostate cancer has been shown to improve biochemical disease-free survival (bDFS) in several studies.

In the same group of patients, androgen deprivation therapy (ADT) has been shown to confer a survival benefit when combined with radiotherapy doses of up to 70 Gy; however, there is currently little long-term data on patients who have received high-dose intensity-modulated radiotherapy (IMRT) with ADT. We report the long-term outcomes in a large cohort of patients treated with the combination of DE image-guided IMRT (IG-IMRT) and ADT.

METHODS AND MATERIALS: Patients with localized prostate cancer were identified from a centralized database across an integrated cancer center. All patients received DE IG-IMRT, combined with ADT, and had a minimum follow up of 12 months post-radiotherapy. All relapse and toxicity data were collected prospectively. Actuarial bDFS, metastasis-free survival, prostate cancer-specific survival, and multivariate analyses were calculated using the SPSS v20.0 statistical package.

RESULTS: Seven hundred and eighty-two eligible patients were identified with a median follow up of 46 months. Overall, 4.3% of patients relapsed, 2.0% developed distant metastases, and 0.6% died from metastatic prostate cancer. At 5-years, bDFS was 88%, metastasis-free survival was 95%, and prostate cancer-specific survival was 98%. Five-year grade 2 genitourinary and gastrointestinal toxicity was 2.1% and 3.4%, respectively. No grade 3 or 4 late toxicities were reported. Pretreatment prostate specific antigen (P=0.001) and Gleason score (P=0.03) were significant in predicting biochemical failure on multivariate analysis.

CONCLUSION: There is a high probability of tumor control with DE IG-IMRT combined with androgen deprivation, and this is a technique with a low probability of significant late toxicity. Our long term results corroborate the safety and efficacy of treating with IG-IMRT to high doses and compares favorably with published series for the treatment of prostate cancer.

Written by:
Wilcox SW, Aherne NJ, Benjamin LC, Wu B, de Campos Silva T, McLachlan CS, McKay MJ, Last AJ, Shakespeare TP.   Are you the author?
North Coast Cancer Institute, Port Macquarie, NSW, Australia; The University of New South Wales, Rural Clinical School, Sydney, NSW, Australia; North Coast Cancer Institute, Coffs Harbour, NSW, Australia; The University of New South Wales, Rural Clinical School, Sydney, NSW, Australia; North Coast Cancer Institute, Lismore, NSW, Australia; The University of Sydney, Sydney, NSW, Australia.

Reference: Onco Targets Ther. 2014 Aug 30;7:1519-23.
doi: 10.2147/OTT.S65238

PubMed Abstract
PMID: 25210465

UroToday.com Prostate Cancer Section