DESTINATION is a single centre phase II non-randomised study in men with intermediate risk localised prostate cancer.~The aim is to establish the technical feasibility of treating prostate cancer with toxicity-minimising radiotherapy on an MR-linac.~20 men will be recruited to take part. All radiotherapy will be delivered on the MR-linac. The whole prostate with no margin will be treated to 30 Gray (Gy) in 5 fractions (i.e. dose to 95% of the Clinical Target Volume prostate should receive 30 Gy (D95%CTVp= 30 Gy)). The dominant lesion (Gross tumour volume (GTV)) as defined on pre-biopsy multiparametric magnetic resonance imaging (mpMRI) plus a 4mm intra-prostatic margin (GTV4mm) will be treated to 45 Gy in 5 fractions, providing standard organ at risk (OAR) constraints can be met. If not, then dose coverage of the GTV will be reduced until the OAR constraints are met (i.e. isotoxic dose escalation). OAR constraints will be as per international standard levels, and largely consistent with the PACE B trial.~The primary end point will be assessed once 14 patients have completed their radiotherapy treatment on the MR-Linac. If any of the first 14 patients do not complete all five fractions planned, then recruitment will continue until we have 14 assessable patients. The analysis population for the primary endpoint will be defined as those patients who have completed all five fractions of stereotactic body radiotherapy (SBRT) as intended.~If shown to be feasible a total of 20 patients will be recruited to enable a better estimation of the toxicity rates and to further technical proficiency with this technique.
The goal of this feasibility study is to learn about dose de-escalation in the treatment of men with intermediate risk prostate cancer.~The main question it aims to answer is the technical feasibility of treating prostate cancer with toxicity-minimising radiotherapy on an Magnetic Resonance Linear Accelerator (MR-linac). It will also examine gastrointestinal and genitourinary toxicity in the acute and late setting post radiotherapy as well as Prostate-Specific antigen (PSA) control up until 2 years post treatment.~Participants will be treated with radiotherapy to the prostate with which will be given in 30Gy in 5 fractions to the whole prostate and 45Gy in 5 fractions to the dominant lesion.