Radio Frequency Ablation (RFA)

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RFA is a technique in which tumour cell necrosis/ death is caused by direct ablation using thermal energy.

• RFA produces movement of ions in the tissue which results in heating and cellular death. Heating to a temperature of 60-100°C results in almost immediate tissue damage. 
• RFA is based on producing tissue necrosis using a high-frequency alternating current that is delivered through an electrode placed in the centre of the tumour.  Tissue necrosis begins as the temperature approaches 60°C, and RFA treatments often result in local tissue temperatures that approach or exceed 100°C, which result in tumour cell death. 
• It is possible to treat single tumours of up to 5 cm in diameter, and multiple (upto 3) tumours of <3cm diameter.  

• RFA may be performed either under sedation or general anaesthesia. The RFA procedure can be performed under either US or CT guidance. .  
• The procedure would normally be performed in the CT scanner. Once positioned upon the scanning table, the skin over the liver is sterilised and a local anaesthetic is infiltrated into the overlying tissues for pain relief during the procedure. 
• An insulated needle with an electrode at the tip is used which transmits high-frequency alternating current to the tumour tissue.  The needle electrode is inserted into the tumour usually under ultrasound or CT guidance.  
• Following ablation of the tumour, continued heating of the needle on withdrawal or “track ablation” avoids spreading of tumour cells. 

The following factors suggest that RFA cannot be performed: 

• Significant evidence of cancer outside the liver, 
• Invasion of bile ducts or major vessels.  
• Difficult to access lesions or close distance to important structures like vessels and nearby organs ( (may be sometimes necessary to perform RFA under open or laparoscopic surgery.) 
• A relative contraindication may be if lesions are larger than 5 cm: RFA should be used cautiously for lesions larger than 5 cm 

Complications of RFA (2-5%)include:

•  Haemorrhage
• Liver abscess
• Heat injury to adjacent structures e.g. bowel and gallbladder.  

The use of “hydrodissection” (the injection of dextrose solution to push away other nearby organs) can be used to avoid local complications or injury to other structures.