Having radiotherapy to the prostate/prostate bed: preparation for treatment
This page is for patients who are about to start a course of radiotherapy to the prostate/prostate bed.
Before starting radiotherapy planning and treatment you will need to follow special instructions on preparing your bladder and bowels. This preparation process ensures your internal organs (rectum, bladder, small bowel) can be moved away from the area to be treated, and to make sure your internal organs on the treatment days are in the same position as on your radiotherapy planning scan.
It is important that you understand and follow the instructions for preparation given to you.
This page describes what needs to be done and what you need to do throughout your treatment. We understand this is a worrying time for patients and their families, and we hope this page can help to answer any questions you have.
If you have any questions about the treatment or information below, please speak to the team looking after you.
The prostate is a gland about the size and shape of a walnut. The prostate gland is in front of the rectum, just below the bladder and it surrounds the urethra (Figure 1). The urethra carries urine from the bladder out through the penis.
Daily bowel preparation during your treatment is important because:
- It will improve the accuracy of your treatment.
- It will help reduce the risk of any long-term bowel side effects
When having radiotherapy to the prostate/prostate bed it is important that you have a comfortably full bladder and maintain a similar bladder size for each treatment.
The reasons for this are:
- A larger bladder will limit the amount of bladder and small bowel in the treatment area which will help to reduce any side effects you may experience.
- It will help maintain treatment accuracy.
One to two weeks before your radiotherapy CT planning appointment you will be invited to attend a prostate education session. The education session is to help you understand more about the importance of the preparation process.
Depending on your preference, this will either be in the radiotherapy department, via an online Zoom presentation or a phone consultation.
Bladder preparation:
Hydration is essential for your radiotherapy including the planning CT. One week before your planning CT scan, increase your fluid intake so that you are well hydrated. Drink at least two litres of water every day. It is possible to add squash or juice if this makes the water more palatable.
You will need a comfortably full bladder for your radiotherapy planning CT scan and treatment. You will be asked to drink a specific amount of water before each appointment.
We recommend that you do not drink more than two cups of tea or coffee per day, as caffeine will irritate your bladder. Try switching to decaffeinated drinks and/or herbal teas. Try to reduce your alcohol intake.
Please ask your specialist nurse or the radiotherapy review team for further advice.
At your CT planning scan, you will be asked to drink 5 cups of water and comfortably hold in your bladder for 30 to 45 minutes prior to your scan. This will be asked of you every day for treatment.
Bowel preparation:
A daily micro-enema is required to maintain an empty rectum throughout your radiotherapy treatment. This must be carried out even if your regular bowel motions have occurred. Please bring your enemas for all appointments, including your CT planning scan.
You will be prescribed micro-enemas to use daily to prepare your rectum for treatment. The micro-enema causes your rectum to empty with a bowel movement or passing of wind. The micro-enema will need to be inserted into your rectum. You will be asked to do this for yourself. You will be asked to practice inserting the micro-enemas for two days before your radiotherapy CT planning scan.
Once you have had your scan, you will not need to insert the micro-enemas until the first day of your radiotherapy treatment.
A micro (small) enema is medication which will cause your rectum to empty with a bowel movement or passing of wind. The micro-enema is contained in a small tube with a nozzle and is designed for easy insertion into the anus (back passage).
The medication (5mls) is inserted into your rectum via the nozzle. Although the prospect of using a micro-enema everyday sounds unpleasant, most patients tolerate it well.
Go to the toilet with the micro-enema and remove the cap. To make it easier to insert the nozzle into your rectum, squeeze out a drop of fluid and spread it over the nozzle. Gently insert the nozzle fully into your rectum and squeeze out all the contents of the tube.
Keep squeezing the tube as you remove the nozzle. This action prevents the medication from being drawn back into the nozzle.
The need to have a bowel movement is usually felt within 10-15 minutes. If you suffer from haemorrhoids or have problems inserting the micro-enema, please speak to a member of the radiotherapy review team.
Please see the contact details at the end of this page.
You can eat and drink normally before you come for your planning CT scan. You will be asked to bring your micro-enemas with you. At this appointment the planning radiographers will ask you to:
- Empty your bladder.
- Insert a micro-enema and wait for your bowels to empty. The need to have a bowel movement is usually felt within 10 - 15 minutes. Even if you have already opened your bowels on the day of your scan, you will still need to use a micro-enema to make sure your rectum is empty.
- Drink five cups of water, after you have emptied your bowels. This is available in the waiting area. Do not do this until instructed by a radiographer.
- Wait for 30 - 45 minutes, to allow for your bladder to fill (comfortably), before you have your radiotherapy planning scan. If you do not feel your bladder is full after 30 - 40 minutes, please tell the radiographers.
Please allow around 2 hours for your planning CT appointment.
You can eat and drink normally on the day of your radiotherapy appointment. Please arrive at least one hour before your allotted radiotherapy appointment time.
At each appointment you will need to:
- Empty your bladder.
- Insert a micro-enema and wait for your bowels to empty. The need to have a bowel movement is usually felt within 10 - 15 minutes. Even if you have already opened your bowels on the morning of your treatment appointment, you will still need to use a micro-enema to make sure your rectum is empty.
- After emptying your bowels, the radiographers will tell you when to start drinking the prescribed amount of water that you drank at your planning CT scan. This is available in the waiting area.
- Wait prescribed amount of time advised at your planning CT scan, to allow for your bladder to fill (comfortably), before you have your radiotherapy treatment.
For each radiotherapy appointment, you should allow up to two hours. You should aim to arrive at least an hour before your given treatment appointment time, to allow for the above process. It is important that you understand and follow the instructions for treatment preparation given to you.
If you have any difficulty following the instructions, please discuss this with the radiographers treating you. There may be various reasons for this problem, including side effects to your bladder and bowels.
You should only modify the routine for your bladder/bowel preparation after discussion and agreement with your radiotherapy doctor.
If you still have any questions or concerns, please let your doctor, radiographer or radiotherapy review team know. We are here for you.
Do I need to use the micro-enemas over the weekend?
No, you only use the micro-enemas on the days that you attend for your radiotherapy treatment.
Can I eat after inserting a micro-enema?
Yes, you can eat normally after inserting a micro-enema.
Even if I have emptied my bowels naturally, do I still need to use a micro-enema before my treatment?
Yes, even if you have already opened your bowels naturally on the day of your treatment, you will still need to use a micro-enema to make sure your rectum is empty.
For advice about treatment side effects
Radiotherapy review team (via radiotherapy reception)
t: 020 3447 3700/01
For any other question about your condition
Uro-oncology CNS team
e: uclh.
For information about appointments
Radiotherapy reception
t: 020 3447 3700/ 020 3447 3701
For information, support, or any other queries
Macmillan support and information team
t: 07816 096619
e: uclh.
Out of hours oncology advice number (available 24 hours)
t: 07947 959020
If you have any concerns that you would like to discuss in confidence, please contact our PALS (Patient Advice and Liaison Service) for information and advice.
t: 020 3447 3042
Prostate Cancer UK
t: 0800 074 8383
e: helpline
w: www.
Tackle Prostate Cancer
t: 0800 035 5302
e: helpline
w: www.
ORCHID Fighting Male Cancer
t: 0808 802 0010
e: helpline
w: www.
Errol McKellar Foundation (Black Afro-Caribbean men with prostate cancer)
w: www.
Metro Walnut (peer support group for LGBTQ people with prostate cancer)
w: www.
Live Though This (LGBTIQ+ Cancer Support)
w: www.
UCLH cannot accept responsibility for information provided by other organisations.
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Page last updated: 20 December 2024
Review due: 30 September 2025