Brachytherapy for prostate cancer

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Brachytherapy is a type of radiotherapy, which uses tiny radioactive pellets or seeds put inside your prostate. 

The seeds release radiation slowly over a number of months. The radiation destroys prostate cancer cells. The seeds are not removed and the radiation fades away over time. 

The aim of brachytherapy is to fully cure your prostate cancer.

High dose-rate (HDR) brachytherapy: Instead of using permanent seeds, a temporary source of radiation is inserted into the prostate gland for a few minutes. 

Who can have brachytherapy?

Your doctor will let you know if you are suitable for brachytherapy. 

You may not be suitable if you have trouble passing urine, have a very large prostate gland or have recently had surgery to your prostate gland. 

  • If you have a larger prostate gland - you may be given hormone therapy to shrink it before brachytherapy. 
  • If you have higher-risk prostate cancer - you may receive brachytherapy along with another treatment. For example, you may need some doses of external beam radiotherapy or hormone therapy as well.

Before brachytherapy 

A few weeks before you will have a trans-rectal ultrasound scan of your prostate. 

The scan pictures will show the exact size and shape of your prostate so the doctor knows how many seeds need to be used and where they should be placed. 

The day before the seeds are put in (implanted), you may be asked to follow a special diet and have an enema to clear your bowels. An enema is a fluid solution gently put into your bowel through your back passage.

Putting in the brachytherapy seeds 

You will be taken to an operating theatre to have the seeds put in under a general or spinal anaesthetic. An ultrasound probe is first put in your back passage to show up your prostate. Then about 60 to 120 radioactive seeds are put into your prostate through the skin between your scrotum and anus using a fine needle. You will not be cut. It takes about 90 minutes to put in all the seeds.

After brachytherapy

  • A tube (catheter) will be put into your bladder during the operation. The tube will drain any urine. It may be left in for a couple of hours or overnight.
  • Mild soreness and some bruising between your legs can happen after the seeds have been put in. Your doctor can prescribe mild painkillers to relieve this.
  • Blood can appear in your urine afterwards, but most bleeding usually goes within 48 hours. If it goes on beyond that, let your doctor know. 
  • You will be given antibiotics to prevent an infection. 
  • You may be given alpha blockers. Alpha blockers are tablets to help relax your bladder and make it easier to pass urine. 

Usually you will be able to go home the same day once you have recovered from the anaesthetic and can pass urine normally. 

Hints and tips

  • To help prevent blood clots and flush out your bladder, drink plenty of fluids (about 1½ to 2 litres a day).
  • Do not drive for 24 hours after having a general anaesthetic.
  • Take it easy and avoid heavy lifting and straining for 2 or 3 days.
  • It is safe to bathe or shower any time after the seeds are put in.
  • Return gradually to your regular diet.
  • Avoid foods that may irritate your bowel and avoid getting constipated.
  • There’s a slight chance that a seed could be passed out in your semen or urine, although this is rare. If you do pass a seed, tell the radiotherapy unit. Don’t handle the seed with your fingers and flush it down the toilet.
  • Carry a medical alert card with you, if you’re given one. This tells medical professionals and airline security staff that you have radioactive implants. 

You will be given a follow-up appointment 4 to 6 weeks after your brachytherapy to check the positioning of the seeds with a CT scan.

Read more about follow-up.

Is the radiation safe?

The radiation is released into your prostate gland over the first few months. After about 12 months, the seeds are no longer active.  The seeds can stay in your prostate without doing any harm. 

  • It is safe for you to be around other people and pets during this time. 
  • As a precaution it is best to avoid close physical contact (less than an arm’s length) with small children or pregnant women for the first 2 months after treatment. 
  • Follow the advice from the hospital about any specific precautions you need to take. 

Brachytherapy side-effects

Any side-effects are usually at their worst a few weeks after the seeds have been put in.
Side-effects include:

  • Urinary problems 
  • Erectile dysfunction (impotence)
  • Bowel problems
  • Fatigue (tiredness)
  • Infertility

Urinary problems

  • A burning sensation when you pass urine
  • Needing to pass urine more often
  • Having a slow stream
  • Finding it harder to start passing urine
  • Needing to go more quickly than you used to
  • Not being able to pass urine (urinary retention). This is rare.

Urinary problems can happen because radiation can irritate and inflame the tube through which you pass urine (urethra) and your bladder. 

Urinary side-effects usually improve over time as the seeds lose some of their radiation.

Leaking urine (incontinence) is rare after brachytherapy. If you have had surgery to your prostate gland before brachytherapy, you will have a higher risk of incontinence.
Read more about urinary symptoms and how to manage them


Erectile dysfunction (impotence)

  • Being unable to get or keep an erection strong enough for sex

Erectile dysfunction can happen because brachytherapy can damage the nerves and blood vessels that control erections.

You may not notice it until years after your treatment. It may also become a long-term problem or be permanent. 

  • 2 years after brachytherapy, 2 out of 10 men have erectile dysfunction. 
  • 3 years after brachytherapy, 4 out of 10 men may have it. 

Your risk of erectile dysfunction will increase if you have had erection problems before your treatment or if you have hormone therapy and external beam radiotherapy as well as brachytherapy.

Read more about erectile dysfunction and how to manage it.


Bowel problems

  • Bleeding when you go to the toilet.
  • A change in your bowel habit, such as needing to go to the toilet more often. 

Bowel problems can happen because brachytherapy can irritate the bowel, which is near your prostate gland. 

Bowel problems can appear straight away or up to 2 to 3 years after your treatment. If this happens, talk to your doctor. There may be treatments that can help. It’s important that any doctor who treats you for bowel problems after brachytherapy is aware that you have had brachytherapy. 

Fatigue (tiredness)

You may experience tiredness from the anaesthetic or from getting up a lot at night to pass urine. It usually takes a few months for this to improve after treatment. Read more about coping with fatigue.


Radiation can affect your fertility, so you may not be able to father a child in the future. 

Talk to your doctor before your treatment if you’re worried about this. It’s not safe to assume you are sterile, so you will need to use contraception to avoid pregnancy. Read more about fertility and cancer treatment.

Sex after brachytherapy

  • Talk to your doctor or nurse about when you can start having sex again after brachytherapy.
  • You should wait at least 2 weeks after treatment before having sex. It may be a while before you feel like having sex if you’re sore or tired.
  • It is safe for you and your partner to sleep in the same bed (if your partner is not pregnant). 
  • There is a small risk that a seed may come out in your semen when you are having sex. You should use a condom to catch the semen the first 4-5 times you have sex. 
  • Don’t worry if your semen is black or brown in colour. This is normal and due to bleeding when the seeds are put in.

Advantages and disadvantages of brachytherapy


  • Treatment time is short: 1-2 days.
  • You can return to your normal routine quite quickly.
  • Compared to external radiotherapy, brachytherapy may have fewer immediate side-effects and cause less damage to surrounding tissues like the back passage, urethra and bladder.


  • It can cause urinary, erection and bowel problems.
  • You may have some temporary discomfort after the procedure.
  • You will need to have a general anaesthetic.
  • You may not be able to have prostate surgery in the future, due to the effects of the radiotherapy.

For more information

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