Locally ablative therapies for primary and metastatic liver cancer

Abstract

Locally ablative therapies have an increasing role in the effective multidisciplinary approach towards the treatment of both primary and metastatic liver tumors. In patients who are not considered surgical candidates and have low volume disease, these therapies have now become established into consensus practice guidelines. A large range of therapeutic options exist including percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation, percutaneous laser ablation (PLA), irreversible electroporation (IRE), stereotactic body radiation therapy (SBRT) and high intensity focused ultrasound (HIFU); each having benefits and drawbacks. The greatest body of evidence supporting clinical utility in the liver currently exists for RFA, with PEI having fallen out of favor. MWA, IRE, SBRT and HIFU are relatively nascent technologies, and outcomes data supporting their use is promising. Future directions of ablative therapies include tandem approaches to improve efficacy in the treatment of liver tumors.

Keywords::

• ablation
• hepatocellular carcinoma
• high-intensity focused ultrasound
• liver
• metastasis
• microwave
• radiofrequency
• radiosurgery
• stereotactic body radiation therapy
• thermal

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• The management of both primary tumors and metastases confined to the liver is best served with a multidisciplinary approach as adopted by multiple consensus guidelines.

• Locally ablative therapies are well established in both National Comprehensive Cancer Network and European Association for the Study of Liver guidelines as a curative intent treatment in nonsurgical candidates in both primary and metastatic liver tumors with a low-volume disease burden.

• Radiofrequency ablation (RFA) is well established with multiple prospective randomized clinical studies validating its efficacy in improving overall survival, particular in comparison to other ablative techniques such as percutaneous ethanol injection.

• Microwave ablation, high-intensity focused ultrasound and stereotactic body radiation therapy are all relatively nascent technologies, though preliminary data regarding their use are promising, with overall survivals similar to RFA.

• Irreversible electroporation is in preliminary phases of clinical validation, though its high safety profile, may expand the role of local ablation to patients previously deemed ineligible.

• The synergistic use of locally ablative therapies in combination with other treatment options has already been clinically validated with improved overall survival demonstrated with RFA and TACE compared with RFA alone.

• Exciting future directions of research include the use of thermal ablation in tandem with stereotactic body radiation therapy as their synergistic effect has already been proven in animal models, and the techniques are complimentary from a technical standpoint and readily adaptable into clinical practice.

Notes