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Patient information
Preparing for SABR to your prostate
What is SABR?
SABR stands for Stereotactic Ablative Body Radiotherapy. It is also known as SBRT (Stereotactic
Body RadioTherapy). Stereotactic radiotherapy is an effective way of giving more accurate
radiotherapy over fewer treatment sessions, to increase the chances of controlling the tumour.
Numerous x-ray beams of high energy are used to deliver a high dose of radiation from outside the
body to the tumour, while sparing the surrounding normal tissues as much as possible. It provides
an increased chance of tumour control compared to a course of standard radiotherapy alone.
In some people the cancer stays the same size and becomes dormant, and in others it may shrink.
It can be delivered on either a linear accelerator (linac), the CyberKnife or on the MR Linac,
depending on which the radiotherapy team think is the best suited to your cancer. The choice is
made on a number of different factors, and involves your clinical oncologist, physicists and
radiographers at our weekly multi-disciplinary meeting (MDT).
The prostate can move during treatment, however, there are some simple things that you can do
to further improve the accuracy of the treatment and reduce any possible side effects.
Preparing your bladder
If your bladder is well filled with urine during treatment, it pushes the bowel away from the
radiotherapy and can reduce bowel side effects. It is also important that your bladder is a similar
size during each treatment. To do this for the CT scan, MRI scan and each treatment, we will ask
you to empty your bladder, drink two cups of water immediately (approximately 350 mls) and then
wait either 30-40 minutes for those having treatment on the CyberKnife and MR Linac, or one hour
for those having treatment on a linac. We would like you to start each treatment with the feeling
of a moderately full bladder.
Preparing your bowel
Your prostate moves slightly when faeces or gas pass through your rectum. If we can reduce bowel
movement during your treatment it will stop the prostate being 'squashed' and changing shape
during treatment, and will make the treatment quicker. To do this, we ask you to use an enema
inserted into the back passage (rectum) to stimulate a bowel movement - these will provided by
the pharmacy. We need you to use the enemas for two days before your planning CT and MRI scan
and on the morning of the scans.
You will then need to use the enemas two days before your first treatment and on the day, prior to
your first treatment. After that, please take the enemas on each day of treatment (but not any
Radiotherapy Department Page 2 of 2
Revised: January 2020 Planned review: January 2023
© The Royal Marsden NHS Foundation Trust RT-1307-05
days in between treatments) until the radiotherapy is finished. If you get diarrhoea during this
time, then stop taking the enemas and discuss this with the radiographers.
The table below will help you keep track of your appointment dates so you know when you need to
take the enemas.
CT and MRI scan
Day 1 SABR
Day 2 SABR
Day 3 SABR
Day 4 SABR
Day 5 SABR
Contact details
Radiotherapy Key Worker: ____________________________________________
Radiotherapy Department Sutton:
0208 915 6020
Radiotherapy Department Chelsea:
0207 808 2540
CyberKnife Chelsea Reception:
020 7811 8467
The Royal Marsden Help Centre can provide further general information and support. Call in or
phone (Freephone):
0800 783 7176
Alternatively, please call:
The Royal Marsden Macmillan Hotline:
020 8915 6899
(available 24 hours a day, 7 days a week)