Thermal or cryoablation to treat a tumour

This information is about having a procedure called thermal ablation or cryotherapy (cryoablation) to treat a tumour.

Ablation is a way to destroy tumours without surgery. We put in one or more needles (electrodes) through the skin. They accurately target the tumour and deliver energy (heat or cold) to it.  This destroys the tumour cells by burning or freezing the tumour.

Sometimes, you need 2 or more treatment sessions before the tumour is completely destroyed.

A specialist called an interventional radiologist (IR doctor) does the ablation procedure. IR doctors are experts in minimally invasive, image-guided procedures. We have a team of highly skilled IR doctors who provide this treatment.

Ablation is now increasingly used to treat solid tumours in the:

It can easily be combined with:

  • other treatments involving medicines, such as chemotherapy
  • external radiotherapy (where a machine is used to aim beams of radiation at the cancer)

The aim of this information is to help answer some of your questions about having thermal ablation or cryoablation. It explains:

If you have any more questions or concerns, please contact the interventional radiology (IR) department.

Technologies used for ablation

We use radiofrequency (heat), microwaves (heat) and cryoablation (cold) to destroy tumours without surgery. Needles (electrodes) are inserted under CT or ultrasound scan guidance, or a combination of both.

Radiofrequency ablation

Radiofrequency ablation involves heating tumours with radiofrequency energy.

In this procedure, the IR doctor guides a small needle through the skin into the tumour. Radiofrequency energy passes from the tip of the needle into the tumour. This produces heat and burns the surrounding tumour cells.

In the case of microwaves, the tip of the needle releases electromagnetic waves. They boil the water inside the tumour cells to destroy them.


Cryotherapy freezes tissues instead of burning them. The IR doctor puts small needles through the skin to circulate very cold gases. This freezes the tumour and destroys the tumour cells.

Types of tumours that can be treated with ablation

Several different types of solid tumours can be treated with thermal ablation or cryotherapy. We usually do an ablation procedure to treat small (less than 5cm across) tumours of the:

  • liver
  • kidneys
  • lungs
  • bones
  • spine
  • adrenal glands (small glands on top of both kidneys that make chemical messengers called hormones)

We can get the best results when treating single, small tumours (less than 3cm) that have not spread to other parts of your body.

Benefits of the procedure

Most people who have a thermal ablation or cryoablation procedure can leave hospital the next day. Usually, they can then resume their everyday activities within a few days and there is no significant effect on their overall health. 

There are other benefits to the ablation procedure:

  • You can have the procedure under a general anaesthetic or sedation. A general anaesthetic is a medicine to make you sleep during the procedure. Sedation is a medicine to make you feel relaxed and sleepy. We talk to you at your appointment about which method is most suitable.
  • Most people cope with the procedure well. You can usually resume your routine the next day. However, you may feel tired and have some pain in the treated area for a few days.
  • There are low complication rates.
  • We may be able to repeat the procedure, if needed.
  • The procedure can be combined with other treatment options, such as chemotherapy and radiotherapy.

Risks of the procedure

As with any medical procedure, there are some risks involved if you have ablation. However, we use CT or ultrasound scans, or X-rays, to guide the treatment precisely to the affected tissue.  This means that complications are rare.

The possible complications are listed in this section.


You may have bleeding in the abdomen (the lower part of the body containing the stomach, bowels and other organs). This is uncommon, but may mean that you need either:

•    a blood transfusion (when we give you blood from someone else)
•    another procedure to stop the bleeding


We usually treat an infection with antibiotics. Infection can cause an abscess (lump containing pus), but we can drain this if needed.


If the tumour is on your lung, there is a risk of air leaking out of the lung. This is called a collapsed lung or pneumothorax. If this happens, you may:

  • feel short of breath
  • have a continuous cough
  • have some chest pain

We can treat a pneumothorax by draining the air, but your hospital stay after the procedure will be longer.

Injury to other parts of the body

Depending on where the tumour is in your body, other organs like the bowel or stomach could be injured during the procedure. This is very rare and can be treated, but you may need more surgery.

Injury to the nerves

If the tumour is near the spine or other sensitive nerves, they can be damaged. This complication is rare but you may need more treatment if it happens.

Radiation risks

During the ablation procedure, you are exposed to X-rays. They are a type of radiation called ionising radiation. This may cause cancer many years or decades after you are exposed to it.

You might have some skin redness after the procedure that feels like sunburn. We do not expect this to be permanent. The redness might be harder to notice on brown and black skin. 

Interventional radiology (IR) is when we use medical imaging guidance to do minimally invasive procedures. The amount (dose) of radiation from these procedures is generally low. More complex procedures might involve a medium (moderate) dose of radiation.

The IR doctor and radiographer (health professional who specialises in medical imaging) make sure that:

  • your radiation dose is kept as low as possible
  • the benefits of having X-rays during your procedure are greater than the radiation risks

Radiation and pregnancy

Radiation can be harmful for an unborn baby. If you are or think that you might be pregnant, it is important to tell a member of your medical team before the procedure.
If you can become pregnant from sex, you need to use protection (contraception) from the first day of your period until your appointment. This means that you will not be pregnant when you have the procedure.

If the first day of your period has already passed, please contact the interventional radiology (IR) department. We can then give you another appointment within the first 10 days of your period. 

We ask you to sign a pregnancy declaration form before the procedure.

Other treatment options

There are other ways to treat tumours, including:

  • surgery
  • chemotherapy (treatment with medicine that damages cancer cells)
  • vascular embolisation (a procedure that cuts off the tumour's blood supply)

Another treatment option is external radiotherapy. This is when we aim beams of radiation from a machine at the tumour over several sessions to kill the cancer cells.

These other treatment options may not be suitable for you. Please ask your doctor for more information.

Resource number: 0246/VER5
Last reviewed: March 2024
Next review due: March 2027

A list of sources is available on request.

Trusted Information Creator. Patient Information Forum

Contact us

If you have any questions or concerns about ablation, please contact the interventional radiology (IR) department.


We are open from Monday to Friday, 9am to 5pm.

The secretary arranges for an IR doctor or clinical nurse specialist to call you back.

Outside of working hours, you can call 111 or go to your nearest emergency department (A&E).

Pharmacy medicines helpline

If you have any questions or concerns about your medicines, please speak to the staff caring for you. 

You can also contact our pharmacy medicines helpline.

Phone: 020 7188 8748, Monday to Friday, 9am to 5pm

Email: [email protected]

We aim to respond to emails within 2 working days.

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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