The study will examine stereotactic ablative body radiotherapy (SABR), a new technique to deliver radiotherapy to men with prostate cancer. In addition to this, it will look at the effect of SABR on levels of markers of radiation exposure and bowel damage, along with other potential markers of outcome and side effects. Quality of life and any side effects that develop during and after treatment will also be assessed.

The study will examine stereotactic ablative body radiotherapy (SABR), a new technique to deliver radiotherapy to men with prostate cancer. In addition to this, it will look at the effect of SABR on levels of markers of radiation exposure and bowel damage, along with other potential markers of outcome and side effects. Quality of life and any side effects that develop during and after treatment will also be assessed.

Participants will be treated with five treatments (instead of the standard 37). This is more convenient for them and also allows the treatment of many more people in the same time frame, which should improve the timely delivery of radiotherapy for all patients.

Thirty men with high-risk prostate cancer will be enrolled into the study. They will all be treated with hormone therapy and radiotherapy to the prostate and seminal vesicles. In addition, half of the men will receive an additional dose of radiation to their pelvis. Gold markers will be placed in the prostate before radiotherapy to allow precise targeting of the prostate during treatment. CT scans are taken before and after each treatment to ensure the accuracy of its delivery.

Blood urine and prostate tissue samples will be taken before, during and after radiotherapy. Side effects and quality of life will also by assessed during this time.

Ultimately, this may allow us to predict which men are at increased risk of side effects from radiotherapy and allow closer monitoring, earlier intervention and perhaps alternative treatments in some cases. This should improve the control of prostate cancer and reduce the risk of serious treatment-related side effects

Inclusion Criteria:

Patients with histologically confirmed prostate adenocarcinoma who elect for radical radiotherapy, with at least one of the following features:

• clinical stage T3a N0 M0
• Gleason score 7 (4+3) or above
• PSA > 20

No evidence of nodal or distant metastatic disease

WHO performance status 0-2

Life expectancy of at least 5 years

Men greater than or equal to 18 years

Ability to understand and willingness to sign a written informed consent document (completed prior to registration and subsequent randomization), along with willingness to co-operate with follow-up

Planned to receive 12-36 months of ADT as part of standard treatment

Exclusion Criteria:

T stage greater than or equal to T3b / T4

Prostate volume > 90cc

Current evidence of:

• inflammatory bowel disease or other chronic bowel disorder
• Autoimmune disease
• Active uncontrolled bacterial, viral or fungal infection
• Serious uncontrolled concomitant disease
• Known coagulopathy or bleeding diasthesis
• Anticoagulation medication (if unsafe to insert for seed insertion)
• Bilateral hip prosthesis or fixation which would interfere with standard radiation beam configuration
• Concurrent experimental or cytotoxic drugs
• Allergy to gold
• Severe lower urinary tract symptoms - International Prostate Symptom Score (IPSS) > 19
• Any other contra-indication to hormonal therapy or radical radiotherapy.

History of:

• Previous major abdominal surgery or history of bowel adhesions
• Prior pelvic radiotherapy
• Active malignancy within the preceding five years (other than basal cell carcinoma)

Evidence of:

- Castrate-resistance (rising PSA with castrate levels of testosterone on LHRHa and anti-androgen)

Men with newly diagnosed high-risk localized prostate cancer

We would welcome collaboration with other researchers as long as full ethical approval was granted

Not applicable - no masking