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Aims: The treatment of prostate cancer has evolved markedly over the last 40 years, including radiotherapy, notably with escalated dose and targeting. However, the optimal treatment for localised disease has not been established in comparative randomised trials. The aim of this article is to describe the history ofprostate radiotherapy trials, including their quality assurance processes, and to compare these with the ProtecT trial.Materials and methods: The UK ProtecT randomised trial compares external beam conformal radiotherapy, surgery and active monitoring for clinically localized prostate cancer and will report on the primary outcome (disease-specific mortality) in 2016 following recruitment between 1999 and 2009. The embedded quality assurance programme consists of on-site machine dosimetry at the nine trial centres, a retrospective review of outlining and adherence to dose constraints based on the trial protocol in 54 participants (randomly selected, around 10% of the total randomised to radiotherapy, n ¼ 545). These quality assurance processes and results were compared with prostate radiotherapy trials of a comparable era.Results: There has been an increasingly sophisticated quality assurance programme in UK prostate radiotherapy trials over the last 15 years, reflecting dose escalation and treatment complexity. In ProtecT, machine dosimetry results were comparable between trial centres and with the UK RT01 trial. The outliningreview showed that most deviations were clinically acceptable, although three (1.4%) may have been of clinical significance and were related to outlining of theprostate. Seminal vesicle outlining varied, possibly due to several prostate trials running concurrently with different protocols. Adherence to dose constraints inProtecT was considered acceptable, with 80% of randomised participants having two or less deviations and planning target volume coverage was excellent.Conclusion: The ProtecT trial quality assurance results were satisfactory and comparable with trials of its era. Future trials should aim to standardise treatment protocols and quality assurance programmes where possible to reduce complexities for centres involved in multiple trials. 2016 Published by Elsevier Ltd on behalf of The Royal College of Radiologists.

Summary Background Prostate cancer might have high radiation-fraction sensitivity, implying a therapeutic advantage of hypofractionated treatment. We present a pre-planned preliminary safety analysis of side-effects in stages 1 and 2 of a randomised trial comparing standard and hypofractionated radiotherapy. Methods We did a multicentre, randomised study and recruited men with localised prostate cancer between Oct 18, 2002, and Aug 12, 2006, at 11 UK centres. Patients were randomly assigned in a 1:1:1 ratio to receive conventional or hypofractionated high-dose intensity-modulated radiotherapy, and all were given with 3–6 months of neoadjuvant androgen suppression. Computer-generated random permuted blocks were used, with risk of seminal vesicle involvement and radiotherapy-treatment centre as stratification factors. The conventional schedule was 37 fractions of 2 Gy to a total of 74 Gy. The two hypofractionated schedules involved 3 Gy treatments given in either 20 fractions to a total of 60 Gy, or 19 fractions to a total of 57 Gy. The primary endpoint was proportion of patients with grade 2 or worse toxicity at 2 years on the Radiation Therapy Oncology Group (RTOG) scale. The primary analysis included all patients who had received at least one fraction of radiotherapy and completed a 2 year assessment. Treatment allocation was not masked and clinicians were not blinded. Stage 3 of this trial completed the planned recruitment in June, 2011. This study is registered, number ISRCTN97182923. Findings 153 men recruited to stages 1 and 2 were randomly assigned to receive conventional treatment of 74 Gy, 153 to receive 60 Gy, and 151 to receive 57 Gy. With 50·5 months median follow-up (IQR 43·5–61·3), six (4·3%; 95% CI 1·6–9·2) of 138 men in the 74 Gy group had bowel toxicity of grade 2 or worse on the RTOG scale at 2 years, as did five (3·6%; 1·2–8·3) of 137 men in the 60 Gy group, and two (1·4%; 0·2–5·0) of 143 men in the 57 Gy group. For bladder toxicities, three (2·2%; 0·5–6·2) of 138 men, three (2·2%; 0·5–6·3) of 137, and none (0·0%; 97·5% CI 0·0–2·6) of 143 had scores of grade 2 or worse on the RTOG scale at 2 years. Interpretation Hypofractionated high-dose radiotherapy seems equally well tolerated as conventionally fractionated treatment at 2 years. Funding Stage 1 was funded by the Academic Radiotherapy Unit, Cancer Research UK programme grant; stage 2 was funded by the Department of Health and Cancer Research UK.