Percutaneous Tumour Ablation

(Radiofrequency ablation and cryoablation)

Dr Farhan Ahmad, Consultant Radiologist at the Royal Berkshire Hospital is an expert in tumour thermal ablation, a relatively novel, but increasingly routine way of treating tumours. He regularly performs cases within the NHS and private sectors. Patient selection is crucial and all potential cases are routinely discussed in a multidisciplinary setting before deciding the best approach. This webpage describes in some detail the procedure itself, its risk and benefits, but if you would like to discuss your particular situation further with Dr Ahmad please call Berkshire Imaging on 0118 921 3177

What is Percutaneous thermal tumour ablation?

Percutaneous thermal tumour ablation is a technique developed over the past 20 years for the treatment of certain tumours. “Percutaneous” means through the skin and ablation means destruction (of tissue). “Percutaneous thermal tumour ablation” is therefore a technique where either very high or low temperatures are used to destroy tumour cells.

Radiofrequency ablation (RFA) and microwave ablation (MWA) are common heat treatment techniques. Cryoablation treats tumours by freezing them. The energy to heat or freeze the tissue is delivered through thin needles. These needles are inserted through the skin into the tumour under image guidance using a CT scanner and sometimes an ultrasound machine. The tip of the needle is then either heated or cooled to destroy the tumour cells.

How are tumours normally treated?

The treatment of choice for many tumours in the kidney, liver or lung is surgical excision (removal). This may be performed by open surgery or keyhole (laparoscopic) surgery and may require removal of the whole organ (for example kidney) or the affected part only. These procedures are not suitable for all patients. Some patients may not be fit for surgery and others may have poor organ function (for example kidney failure) which surgery can worsen. Others may not wish to undergo a surgical procedure. In these situations, percutaneous thermal tumour ablation may be an option. Just like surgery it can be used in conjunction with other cancer treatments including chemotherapy and radiotherapy.

 

FIGURE 1

LEGEND: Example of a needle. This Radiofrequency ablation needle extends to form an umbrella shape once inserted in to the tumour. This allows a greater area to be treated.

Which tumours can be treated?

Radiofrequency ablation has been assessed and approved for use by the National Institute for Clinical Excellence (NICE) in the treatment of kidney, liver and lung tumours. It is also (less commonly) used in the treatment of other isolated tumours. Cryoablation likewise has been approved by NICE in treating small kidney tumours. Microwave ablation has also been assessed by NICE in the treatment of secondary liver tumours and can be used although experience with this technology is more limited. See section on finding further information for details on guidance documents published by NICE

How successful is percutaneous thermal tumour ablation?

The strength of evidence now means that these techniques are used widely, in particular for those who are too unfit or unwell to undergo surgery. While there are no studies at present which directly compare percutaneous thermal ablation to surgery, evidence demonstrates that when tumours are few in number and small in size (typically less than 3 to 4cm) results compare favourably to other treatment options (including surgery and chemotherapy) in terms of achieving successful tumour destruction and patient survival. While there is good longer term (5 year) follow up data for patients with small liver tumours, the follow up period in many of the larger studies for kidney and lung tumours are still limited and we must therefore be cautious about the longer term results. This is why we carefully monitor patients with CT scans after treatment. Ask the doctor treating you and see NICE guidance below for a more detailed discussion on the evidence related to different tumour types.

What are the benefits and risks of percutaneous thermal tumour ablation?

As with all treatment options there are both benefits and risks related to percutaneous tumour ablation. These are listed in Table 1 and 2 respectively.

Many if not all the benefits of percutaneous thermal tumour ablation derive from its minimal access technique (pin hole rather than key hole). Elderly patients may therefore benefit from this the most due to minimal trauma and faster recovery times.

Pain after a procedure is common but can be normally well controlled with tablets. Major complications such as severe bleeding, infection (abscess) formation or damage to other structures such as bowel are generally rare (1-2% or less). The risk of requiring further treatment for the same tumour or recurrence of tumour at the same site varies according to many factors (most importantly the size and type of tumour). These risks would be discussed before any treatment is undertaken.

Table 1

Benefits of percutaneous thermal tumour ablation

  • Minimally invasive procedure which avoids open surgery
  • Short procedural time compared to surgery
  • Low rate of post operative complications (less than surgery)
  • Minimal blood loss and low likelihood of receiving a blood transfusion
  • Less post procedural pain compared to surgery
  • Shorter recovery period and hospital stay compared to surgery
  • Preservation of organ function

Table 2

Limitations / risks of percutaneous thermal tumour ablation

  • Higher risk of residual disease after treatment and local recurrence with larger tumours
  • Generally only suitable if disease limited to the organ being treated
  • Risk of major complications (But still much lower than equivalent surgical options)
  • Uncertainty regarding longer term outcome (beyond 5 years) for some tumours
  • Requirement for regular and long term CT surveillance to assess for tumour recurrence

Who performs percutaneous thermal tumour ablation and what happens during a procedure?

Interventional Radiologists who are specialists in image guided minimal access techniques perform the procedure.

FIGURE 2

LEGEND: A thermal tumour ablation being undertaken for a patient with a kidney tumour. Both a CT scanner and ultrasound machine are used to guide the needle in to the tumour. The entire procedure is performed through a pin hole. Minimal access means minimal trauma and faster recovery.

Percutaneous thermal tumour ablation is performed in the X-Ray department. Patients are positioned on the CT scanner having been given either a general anaesthetic (with the patient asleep) or sedated (awake but drowsy and numb). The CT scanner is then used to take pictures and decide on where the needles should be positioned. One or more needles are then carefully positioned in to the tumour using the CT scanner and / or an Ultrasound machine and the tumour is then heated or frozen depending on the technique being used. The duration of treatment depends on the size of the tumour. Once completed, all needles are removed and a plaster placed over the small pin hole incisions.

What happens after the procedure?

Once the patient has recovered from the general anaesthetic or sedative they can eat and drink as normal. Most commonly they are discharged the following day. Follow up will involve CT scans usually every few months to start with to assess the treated tumour.

FIGURE 3

LEGEND: Example of a right sided kidney tumour treated successfully using radiofrequency ablation.

A: Pre-treatment appearance with the kidney tumour circled

B: Post-treatment appearance. The tumour has been successfully treated (arrow).
The patient was discharged the following day. There has been no tumour recurrence to date.

Is percutaneous thermal tumour ablation suitable for everyone?

As recommended by NICE the decision to offer this treatment to a patient is made by a number of doctors working together in a multi-disciplinary team. An Oncologist, Surgeon and Interventional Radiologist will discuss the case. In particular the type of tumour, its size and location as well as the patients general fitness will be considered. Most commonly selected patients are those who have small tumours and are unfit, unsuitable or unwilling to undergo surgery. Please ask the doctor treating you why they are recommending this treatment.

Where can I find further information?

A good place to start is by asking the doctor looking after you about these techniques. They may refer you to an Interventional Radiologist for further discussion.

The following websites also provide information for patients:

National Institute for Health and Clinical Excellence (NICE): www.nice.org.uk

The following guidance documents have been published by NICE:

British Society of Interventional Radiology (BSIR): www.bsir.org.uk (see patient section)

Cardiovascular and Interventional Radiological Society of Europe (CIRSE): www.cirse.org (see patient section)

Further Information

Patient information sheet

Berkshire Imaging LLP . The Forbury Clinic . 23 Craven Road . Reading . Berkshire . RG1 5LE . Telephone: 0118 921 3177
Click here to email us >