The LDR BURST trial will compare the side effects of two radiotherapy treatments for men with localised prostate cancer. The first treatment is 4D low dose rate brachytherapy where small radioactive seeds are inserted into the prostate gland under ultrasound guidance. A computerised tomography scan is subsequently performed to check seed positioning. Patients usually return home the same day. The seeds emit their radiation over several months before losing their activity.
Stereotactic radiotherapy, an alternative treatment, is a form of external radiation using precise high energy x-rays to target the prostate gland. It is delivered in 5 treatment sessions on alternate days; the full treatment course is completed within 2 weeks.
Stereotactic radiotherapy has recently been approved by the National Health Service following successful results in international trials demonstrating it is safe and effective to give external radiotherapy in five treatment sessions. Delivering a higher dose in each treatment fraction is known as 'ultra-hypofractionation'. Before the treatment, men will undergo a minor procedure, typically under local anaesthetic, to have metallic markers inserted into the prostate to improve visibility of the prostate gland when planning and delivering the treatment.
The side effects of both the radiation treatments are similar. Common side effects include bladder issues, such as needing to urinate more often and having a slower urine flow. Patients might also experience more frequent and looser bowel movements, occasionally with a little blood. Symptoms usually improve over time. Additionally, some men might have trouble achieving or maintaining an erection after radiation treatment, this can often be managed with medications.
Both of the treatments use ionising radiation to destroy the prostate cancer cells which may cause cancer many years or decades after exposure. The chances of this happening are the same whether taking part in this trial or not.
A protective gel, called Barrigel, will be inserted into the space between the prostate gland and the rectum increasing the distance between them. This significantly reduces the dose of radiation to the rectum. The gel can be inserted at the same time as the brachytherapy seed or fiducial marker insertion. The gel is slowly reabsorbed following treatment over the next 3 to 6 months.
The trial will randomly assign 110 men to each radiation treatment to compare their side effects. There is a 50% chance the patient will be assigned to brachytherapy and 50% chance of stereotactic radiotherapy. Patients will be asked to complete four questionnaires prior to starting treatment and at regular time points following treatment. They will be telephoned every 4 weeks for the first 2 months to check on side effects, followed by a face-to-face appointment at 3 months, and a PSA blood test, and then followed up at regular intervals for 5 years.
Men aged ≥18 years at randomisation
The research subject must have capacity to sign a written informed consent document for the trial
WHO performance status 0 - 2
Gleason score 3+3 or 3+4
Clinical and/or MRI stage T1c -T2c, N0-X, M0-X
Histological confirmation of prostate adenocarcinoma within the last 18 months (unless on active surveillance). Patients who were on active surveillance should have an up-to-date MRI within 8 weeks of the decision to treat to confirm organ confined disease.
Previous malignancy within the last 2 years (except basal cell carcinoma or squamous cell carcinoma of the skin), or if previous malignancy is expected to significantly compromise 10-year survival.
Patients under investigation for synchronous primary at time of randomisation