Microwave ablation for the treatment of metastases in the liver - Consultation Document

Interventional procedure consultation document

Microwave ablation for the treatment of liver metastases

Treating liver metastases with microwave ablation

Liver metastases are a type of cancer that has spread (metastasised) to the liver from other parts of the body, usually from the colon or rectum. Microwave ablation can be performed during open abdominal surgery, and involves using ‘keyhole’ surgery (where specialised instruments are inserted through small cuts in the abdomen) or needle puncture through the skin. Whichever method is used, special needles are inserted into the tumour(s), and microwave energy is used to heat the tumour with the aim of destroying the cancer cells.

The National Institute for Health and Clinical Excellence (NICE) is examining microwave ablation for the treatment of liver metastases and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE’s Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about microwave ablation for the treatment of liver metastases.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the provisional recommendations
• the identification of factual inaccuracies
• additional relevant evidence, with bibliographic references where possible.

Note that this document is not NICE’s formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that NICE will follow after the consultation period ends is as follows.

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
• The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the NICE website (www.nice.org.uk/ipprogrammemanual).

Through its guidance NICE is committed to promoting race and disability equality, equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our interventional procedures guidance. In particular, we aim to encourage people and organisations from groups who might not normally comment on our guidance to do so.

In order to help us promote equality through our guidance, we should be grateful if you would consider the following question:

Are there any issues that require special attention in light of NICE’s duties to have due regard to the need to eliminate unlawful discrimination and promote equality and foster good relations between people with a characteristic protected by the equalities legislation and others?

Please note that NICE reserves the right to summarise and edit comments received during consultations or not to publish them at all where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 19 May

Target date for publication of guidance: September 2011

1   Provisional recommendations

1.1   Current evidence on microwave ablation for the treatment of liver metastases raises no major safety concerns. The evidence on efficacy is inadequate in quantity and quality. Therefore this procedure should only be used with special arrangements for clinical governance, consent and audit or research.

1.2   Clinicians wishing to undertake microwave ablation for the treatment of liver metastases should take the following actions.

• Inform the clinical governance leads in their Trusts.
• Ensure that patients and their carers understand the uncertainty about the procedure’s efficacy and provide them with clear written information, including details about other treatment options. In addition, use of NICE’s information for patients (‘Understanding NICE guidance’) is recommended (available from www.nice.org.uk/IPGXXX/publicinfo). [[details to be completed on publication]]
• Audit and review clinical outcomes of all patients having microwave ablation for the treatment of liver metastases (see section 3.1).

1.3   Patient selection should be carried out by a hepatobiliary cancer multidisciplinary team.

1.4   NICE encourages further research into microwave ablation for the treatment of liver metastases. Research should clearly define patient selection criteria and report tumour recurrence and survival. Comparison with other ablative techniques would be useful. NICE may review the procedure on publication of further evidence. 

2   The procedure

2.1   Indications and current treatments

2.1.1   Liver metastases are commonly caused by colorectal cancer or  other malignancies, such as lung and gastric cancer.

2.1.2   Treatment of liver metastases depends on their extent and location. Treatment options include surgical resection, ablation, systemic chemotherapy, different types of arterial embolisation and external beam radiotherapy.

2.2   Outline of the procedure

2.2.1   Microwave ablation aims to destroy tumour cells by heating, resulting in localised areas of tissue necrosis, with minimal morbidity.

2.2.2   The procedure can be performed with the patient under local or general anaesthesia: either percutaneously or during open or laparoscopic surgery. A needle electrode is advanced into each targeted liver metastasis under image guidance and the lesion is ablated. Multiple pulses of energy may be delivered during one session and multiple needle electrodes can be used to treat larger tumours.

2.2.3   Various devices can be used for this procedure.

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at www.nice.org.uk/guidance/IP/381/overview

2.3   Efficacy

2.3.1   A randomised controlled trial (RCT) of 30 patients with multiple colorectal liver metastases treated by microwave ablation or hepatectomy reported mean overall survival of 27 months and 25 months respectively (p = 0.83). In the same study, the mean disease-free survival period was 11.3 and 13.3 months respectively (p = 0.47). A non-randomised controlled study of 53 patients with multiple bilobar liver metastases treated by resection plus microwave ablation or  by resection alone reported disease-free 3-year survival of 17%  and 11%  respectively (p = 0.54). Survival free of hepatic recurrence was 39% and 35% respectively at 5-year follow-up (p = 0.86). A case series of 74 patients with liver metastases reported mean overall survival of 22.1 months. Disease-free survival was 35% (26/74) at 25-month follow-up.

2.3.2   A case series of 100 patients (83 with liver metastases) reported that complete ablation on post-operative CT scan was achieved in 98% of patients with colorectal liver metastases, 90% of patients with carcinoid metastases (origin of primary not stated), and 100% of patients with other metastases (absolute figures not stated).

2.3.3   The Specialist Advisers listed key efficacy outcomes as disease-free and long-term survival.

2.4   Safety

2.4.1  There were no procedure-related deaths following microwave ablation in the RCT of 30 patients, in 2 non-randomised controlled studies of 532 and 193 patients, or in 3 case series of 1606, 1007 and 878 patients.

2.4.2  The non-randomised controlled study of 53 patients reported biliary fistula formation (not otherwise described) in 1 out of 37 patients undergoing combined resection and microwave ablation, and in 1 out of 16 patients undergoing resection alone (significance and follow-up not stated).

2.4.3  Pleural effusion was reported in 2% (4/257) of patients and 9% (14/160) of patients (1 requiring drainage) in case series of 1136 patients (257 with metastases) and160 patients (63 with liver metastases) respectively (follow-up not stated). The case series of 74 patients reported minor to moderate pleural effusion in 9% (7/74) of patients (follow-up not stated).

2.4.4  The case series of 87 patients reported pain requiring termination of the microwave ablation procedure in 1 patient.

2.4.5  The Specialist Advisers listed anecdotal or reported adverse events as abscess, bleeding, infection, pneumothorax, colonic perforation, fever, tumour seeding, and bile duct injury. They considered theoretical adverse events to include deterioration in liver function, and adjacent organ damage to kidney, lung or heart.

3   Further information

3.1   This guidance requires that clinicians undertaking the procedure make special arrangements for audit. NICE has identified relevant audit criteria and is developing an audit tool (which is for use at local discretion), which will be available when the guidance is published.

3.2   This guidance is a review of ‘Microwave ablation for the treatment of metastases in the liver’ NICE interventional procedures guidance 220 (2007).

3.3   For related NICE guidance see www.nice.org.uk

Bruce Campbell

Chairman, Interventional Procedures Advisory Committee

April 2011

_{Personal data will not be posted on the NICE website. In accordance with the Data Protection Act names will be anonymised, other than in circumstances where explicit permission has been given.}

_{It is the responsibility of consultees to accurately cite academic work in order that they can be validated.}