Can we avoid dose escalation for intermediate-risk prostate cancer in the setting of short-course neoadjuvant androgen deprivation?
Authors Shakespeare T, Wilcox S, Aherne N
Received 11 December 2015
Accepted for publication 27 January 2016
Published 17 March 2016 Volume 2016:9 Pages 1635—1639
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 2
Editor who approved publication: Professor Min Li
Thomas P Shakespeare,1,2 Shea W Wilcox,1 Noel J Aherne1,2
1Department of Radiation Oncology, North Coast Cancer Institute, 2Faculty of Medicine, Rural Clinical School, The University of New South Wales, Coffs Harbour, New South Wales, Australia
Background: Both dose-escalated external beam radiotherapy (DE-EBRT) and androgen deprivation therapy (ADT) improve the outcomes in patients with intermediate-risk prostate cancer. Despite this, there are only few reports evaluating DE-EBRT for patients with intermediate-risk prostate cancer receiving neoadjuvant ADT, and virtually no studies investigating dose escalation >74 Gy in this setting. We aimed to determine whether DE-EBRT >74 Gy improved the outcomes for patients with intermediate-risk prostate cancer who received neoadjuvant ADT.
Findings: In our institution, patients with intermediate-risk prostate cancer were treated with neoadjuvant ADT and DE-EBRT, with doses sequentially increasing from 74 Gy to 76 Gy and then to 78 Gy between 2006 and 2012. We identified 435 patients treated with DE-EBRT and ADT, with a median follow-up of 70 months. For the 74 Gy, 76 Gy, and 78 Gy groups, five-year biochemical disease-free survival rates were 95.0%, 97.8%, and 95.3%, respectively; metastasis-free survival rates were 99.1%, 100.0%, and 98.6%, respectively; and prostate cancer-specific survival rate was 100% for all three dose levels. There was no significant benefit for dose escalation either on univariate or multivariate analysis for any outcome.
Conclusion: There was no benefit for DE-EBRT >74 Gy in our cohort of intermediate-risk prostate cancer patients treated with neoadjuvant ADT. Given the higher risks of toxicity associated with dose escalation, it may be feasible to omit dose escalation in this group of patients. Randomized studies evaluating dose de-escalation should be considered.
Keywords: radiotherapy, IMRT, dose, dose escalation, dose de-escalation, androgen deprivation therapy, prostate cancer
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