- Radiofrequency ablation (RFA) was most common – can open, laparoscopic or percutaneous
- Surgical resection superior to RFA for patients with potentially resectable CRLM.
- Microwave has become more popular.
- Uses thermal energy, overcoming RFA’s heat-sink effect and allowing treatment of larger lesions.
- Indications:
- Can be curative alone, or in combination with resection
- Efficacy decreases >3cm
- ESMO guidelines recommend thermal ablation for small CRLM (especially <3 cm) and for recurrence after prior resection
- Caution
- <5mm from bile ducts – stricturing with inadequate drainage and cholangitis
- Vessels – heat sink, decreases efficacy
- Evidence
- The COLLISION RCT (Lancet Oncology, 2024) demonstrated non-inferiority of thermal ablation versus surgical resection for small-size CRLM, with fewer adverse events in the ablation arm
- Local tumour control rates for RFA/MWA range 50–90%; 5-year survival rates range 20–60%, influenced heavily by tumour size, number, and ablation margin
Four techniques:
- Chemical ablation (percutaneous ethanol injection, PEI)
- Thermal ablation (radiofrequency, RFA)
- Microwave ablation (MWA)
- Cryoablation
Radio-frequency ablation
- RFA first line ablation technique. RFA > perc ethanol injection, with lower recurrence and fewer treatment sessions required.
- Advantages:
- Minimally invasive
- Low waiting time
- Preserve uninvolved parenchyma
- No systemic side effects
- Avoid mortality/morbidity risks of major hepatic surgery
- Disadvantages:
- Only small tumours < 3-5 cm likely to be treated successfully
- Technical limitations:
- Multiple tumours (>3) limitation because need for repeat punctures.
- Need to clearly visualise tumour by US; isoechoic tumours in upper segment 4, 7 and 8 or edge of left lateral section may be unsuitable.
- Needle needs to enter tumour via hepatic parenchyma due to risk of intraperitoneal bleeding or seeding – not possible for superficial or protruding tumours
- Does not treat underlying liver disease.
- Recurrence common
- Indications:
- Previously used if patient unsuitable for resectional surgery. However now being considered first-line treatment for single nodules < 2 cm. (RCTs have shown no difference in 5-year survival for HCC < 2 cm)
- Neoadjuvant treatment in liver transplant candidates, and for treatment of recurrence after liver resection.
- Contraindications:
- Gross ascites (risk of intraperitoneal bleeding)
- Uncorrectable coagulopathy
- Previous bilioenteric anastomosis or endoscopic sphincterotomy associated with bile bacterial contamination – risk of abscess
- Proximity to colon, duodenum, stomach or biliary confluence – risk of injury or perforation by heating
- RFA (not microwave) contraindicated with pacemaker
- Methods and margins:
- Ablation should aim to achieve a safety margin to control satellite nodules. 5mm margin.
- Can combine with TACE.
- Treatment response assessed 1 month post procedure.
- Advantages: