Randomised pilot study of dose escalation using conformal radiotherapy in prostate cancer: long-term follow-up |
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Authors: | A Creak E Hall A Horwich R Eeles V Khoo R Huddart C Parker C Griffin M Bidmead J Warrington D Dearnaley |
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Affiliation: | 1.Academic Urology Unit, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Sutton and London, UK;2.Clinical Trials and Statistics Unit (ICR-CTSU), The Institute of Cancer Research, London, UK;3.Joint Department of Physics, Royal Marsden Hospital Trust and The Institute of Cancer Research, Sutton and London, UK |
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Abstract: | Background: Radical three-dimensional conformal radiotherapy (CFRT) with initial androgen suppression (AS) is a standard management for localised prostate cancer (PC). This pilot study evaluated the role of dose escalation and appropriate target volume margin. Here, we report long-term follow-up.Methods: Eligible patients had T1b-T3b N0 M0 PC. After neoadjuvant AS, they were randomised to CFRT, giving (a) 64 Gy with either a 1.0- or 1.5-cm margin and (b) ±10 Gy boost to the prostate alone.Results: One hundred and twenty-six men were randomised and treated. Median follow-up was 13.7 years. The median age was 66.6 years at randomisation. Median presenting prostate-specific antigen (PSA) was 14 ng ml−1. Sixty-four out of 126 patients developed PSA failure. Forty-nine out of 126 patients restarted AS, 34 out of 126 developed metastases and 28 out of 126 developed castrate-resistant prostate cancer (CRPC). Fifty-one out of 126 patients died; 19 out of 51 died of PC. Median overall survival (OS) was 14.4 years. Although escalated dose results were favourable, no statistically significant differences were seen between the randomised groups; PSA control (hazard ratio (HR): 0.77 (95% confidence interval (CI): 0.47–1.26)), development of CRPC (HR: 0.81 (95% CI: 0.40–1.65)), PC-specific survival (HR: 0.59 (95% CI:0.23–1.49)) and OS (HR: 0.81 (95% CI: 0.47–1.40)). There was no evidence of a difference in PSA control according to margin size (HR: 1.01 (95% CI: 0.61–1.66)).Interpretation: Long-term follow-up of this small pilot study is compatible with a benefit from dose escalation, but confirmation from larger trials is required. There was no obvious detriment using the smaller radiotherapy margin. |
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Keywords: | prostate cancer radiotherapy dose escalation phase III randomised controlled trial |
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