Percutaneous Ablation – Intrahepatic cholangiocarcinoma

Current evidence for cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA), the second most prevalent primary liver tumor, still presents a major treatment challenge. As it is usually detected at an advanced stage – often incidentally and asymptomatic – it leaves the vast majority of patients unfit for surgical resection, while recurrence rates remain high, even in cases after resection [1]. Thermal ablation is considered a reasonable alternative treatment option to surgical resection for small, single tumors <3 cm, whether recurrent or primary, provided that safety margins of ≥1 cm can be achieved, making a significant shift in treatment paradigms [2, 3].

While systemic chemotherapy remains the core component of treatment for advanced disease [4], results are still poor. Image-guided locoregional treatments, especially percutaneous thermal ablation, are becoming recognized as valuable treatments in the management of advanced iCCA [5]. Emerging evidence also supports the use of locoregional treatments with systemic therapy to improve effectiveness. In particular, in carefully selected patient groups, preliminary research indicates that this collaborative strategy could deliver safe and promising outcomes [6].

Ablation for cholangiocarcinoma – Current insight

Radiofrequency Ablation (RFA) – has been the most extensively studied ablation method. It relies on the conductivity of liver parenchyma to propagate heat, with efficacy affected by tissue water content and the presence of nearby blood vessel – the “heat-sink” effect. Although RFA is effective in smaller lesions, its inability to generate extensive ablation zones frequently requires the use of multiple probes [7–9].

Microwave Ablation (MWA) – provides several advantages in comparison to RFA. It is less impacted by the heat-sink phenomena and produces higher temperatures rapidly, therefore allowing greater and more predictable ablation zones with less probes. These characteristics make MWA especially appealing in the liver, where proximity to vasculature is common [2, 10, 11].

Cryoablation – as a cold-based technique, it provides real-time visualization of the “ice ball” with all imaging modalities (US, CT, MRI), offering precise control when treating tumors near vulnerable structures such as the gallbladder or intestine. Additionally, compared to heat-based techniques, cryoablation is usually better tolerated with patients reporting less procedural discomfort [12]. However, its limitations include a prolonged procedural time and a higher cost due to the use of multiple probes. While it is also no longer included as a treatment option in the guidelines due to lack of evidence supporting its efficacy.

Irreversible electroporation (IRE) – is a non-thermal ablation technique that induces apoptotic cell death by creating nanoscale pores in cell membranes using high-voltage electric. In contrast to RFA and MWA, IRE is particularly well suited for tumors that are situated in close proximity to critical structures, because it preserves surrounding tissue and remains unaffected by the heat-sink effect. General anaesthesia is a requirement, as is neuromuscular blockade and cardiac synchronization. Although clinical data especially on iCCA remains limited, early evidence suggests IRE may be valuable for treating iCCA in challenging anatomical locations where thermal ablation is not feasible [13, 14].

Future direction

Combining percutaneous ablation with systemic treatments to improve survival will help define the future of iCCA therapy. Particularly thermal ablation coupled with chemotherapy has shown clearly superior outcomes than systemic therapy alone [6]. New strategies, including stereotactic multi-needle ablation and percutaneous thermal segmentectomy, have been developed to improve complete tumor control, particularly for larger lesions, by achieving precise targeting and adequate safety margins. Long-term results using stereotactic radiofrequency ablation have shown a curative ability even in recurrent or unresectable lesions. It is anticipated that continued advancements in technology and knowledge will broaden access to stereotactic procedures and significantly improve patient outcomes [5].