REZUM: water vapour therapy for the prostate

What it is

REZUM is a treatment for benign growth of the prostate, also called benign prostatic hyperplasia (BPH). It uses water vapour to treat the tissue that squeezes the urethra, the tube urine passes through. It is done from inside the urethra, with no cuts in the skin.

Using a thin instrument with a camera, a small needle is placed in the prostate and vapour is applied for a few seconds. The vapour carries heat into the tissue and destroys it. Usually one to three treatments are needed on each side of the prostate, and a few more if there is a middle lobe (a part of the prostate that grows towards the bladder).

Unlike HoLEP or TURP, no tissue is removed: the body gradually absorbs the treated area over the following weeks. That is why the improvement is not immediate and no tissue is left to be examined in the laboratory.

Who may it suit?

Lifestyle changes and medication are tried first. If your symptoms still bother you, or if you do not want to take medication indefinitely, treatments through the urethra are considered. REZUM may suit you if:

• Your symptoms are due to BPH and affect your life despite treatment.
• Your prostate is of moderate size. In the main trials it measured between 30 and 80 ml; there are studies with larger prostates, but with less data.
• Preserving ejaculation matters to you and you prefer a short procedure, even if the improvement is somewhat smaller than with an operation that removes tissue.

It may not be the right option if your prostate is very large, if you have already had urinary retention and have a catheter, if your bladder squeezes weakly or if something else is causing your symptoms, such as a narrowing of the urethra. Other causes are ruled out first and, where appropriate, your PSA is checked.

Your case decides. Before your appointment, you can measure your symptoms with the IPSS test. If you also have your PSA monitored, see the guide High PSA: what it means and what to do.

What the procedure involves

• Anaesthesia. It is done under sedation, without the need for a general anaesthetic.
• The technique. A thin instrument with a camera (cystoscope) is passed through the urethra. From inside, the vapour is applied at the planned points. There are no cuts or stitches in the skin.
• Duration. Applying the vapour takes a few minutes. Including preparation and recovery, the total time at the centre is longer.
• Hospital stay. None is needed: you go home the same day, without staying overnight in hospital.
• Catheter. You go home with a urinary catheter, which stays in for 2 to 5 days, because the prostate swells after the steam.

I will explain at your appointment how many days you are likely to have the catheter.

Afterwards: what to expect

1. The first few days. You will have the catheter for 2 to 5 days. While it is in, your urine may look pink and some discomfort in the area is common.
2. The first few weeks. Once the catheter is removed, it is normal to have stinging, urgency, to go to the toilet more often or to see some blood in your urine or semen. At first you may even pass urine worse than before, because the prostate is swollen. Drink water spread through the day and avoid constipation.
3. After a few weeks. Many men begin to notice that they pass urine better.
4. By about 3 months. The main improvement is usually reached. Your urologist will tell you when your check-up is and whether you can stop your prostate medication.

Side effects and risks

• Stinging, urgency and blood in the urine or semen. These are common in the first few weeks and usually settle on their own.
• Urinary retention. When the catheter is removed, you sometimes still cannot pass urine and it has to be put back for a few days.
• Urinary infection. This can happen, as with any procedure through the urethra.
• Ejaculation and erections. In studies, the great majority of men keep their ejaculation and erections. Some notice less semen.
• Need for further treatment. Over time, some men need to go back on medication or have an operation. I give the figures below.

What studies and the European guidelines say

In a trial of 197 men, REZUM improved symptoms and the strength of the stream compared with a simulated (sham) procedure, and the improvement lasted through 5 years of follow-up. In that trial, about 4 in 100 men needed another operation within 5 years. If men who had to go back on medication are also counted, another study reports about 16 in 100 at 4 years.

Compared with TURP, a 2-year trial found that TURP improves the stream and bladder emptying more, while REZUM was shorter, needed less time in hospital and preserved ejaculation in 98% of men at one year.

The 2026 European Association of Urology (EAU) guidelines list REZUM among the techniques «under investigation»: the results are promising, but they call for more trials against the reference operations, with long follow-up, before giving it a formal recommendation. It is worth knowing this when you decide.

REZUM compared with HoLEP, TURP and green laser

There are several techniques for an enlarged prostate. None is right for everyone:

HoLEP

Removes the obstructing tissue with a laser. It works for prostates of almost any size and the improvement lasts for years, but it needs anaesthesia and a short hospital stay, and retrograde ejaculation is common. I explain it in HoLEP: laser enucleation of the prostate.

TURP

Removes the tissue in small fragments. It improves the stream more than REZUM, with more effects on ejaculation.

Green laser

Vaporises the obstructing tissue instead of removing it.

The choice depends on the size and shape of your prostate, your health, the medication you take and what you value most: the greatest possible improvement, or preserving ejaculation with a shorter recovery. We discuss it at your appointment.

Who performs it

Dr. Mario Domínguez Esteban is a urologist and Head of the Uro-Oncology Section at Marqués de Valdecilla University Hospital. In the private sector he performs it as part of his work at Urología Mínimamente Invasiva (UMI). He is a co-author of a Spanish multicentre study on this technique, cited in the sources.

He is a proctor (trainer of other surgeons) for Boston Scientific, the company that makes REZUM: this is set out in the declaration of interests at the end of this page.

When to seek help

• Seek urgent medical attention if you cannot pass urine, if you have a fever or chills, or if you pass clots in your urine.
• Book a priority appointment with your doctor if, after a few weeks, the stinging, urgency or blood in your urine is not settling.

There is more detail in the warning signs.

Frequently asked questions