COLLISION: Thermal Ablation in Colorectal Liver Metastases

Prof David Kerr discusses a recent trial investigating surgical resection and thermal ablation for small colorectal liver metastases.
https://www.medscape.com/viewarticle/collision-thermal-ablation-colorectal-liver-metastases-2025a10006le?src=soc_yt

-- TRANSCRIPT --
Hello. My name is David Kerr. I’m a professor of cancer medicine at the University of Oxford. I'd like to talk about a study recently published in Lancet Oncology that is of particular relevance to my clinical practice, and I hope of general interest to you, our Medscape colleagues.

It was a trial published by an excellent Dutch group, called “ Thermal ablation versus surgical resection of small-size colorectal liver metastases (COLLISION): an international, randomised, controlled, phase 3 non-inferiority trial.”

This is important. We know that 25% of patients with colorectal cancer will present with hepatic metastatic disease, and more than 50%-60% of patients will die with hepatic metastatic disease. We've become much more rigorous and aggressive in our management of hepatic metastatic disease. My favorite clinical meeting of the week is with our liver multidisciplinary team, supported by fantastic surgical colleagues and a radiological ablationist.

This Dutch trial compared the two. The gold standard is to surgically resect hepatic metastatic disease, if possible, but that comes with significant morbidity costs. There's no doubt that there have been improvements in thermal ablation, through the possibility of passing the electric current down a fine electrode inserted into the nodules and effectively burning them out. The technology has improved, as have the results and safety.

There's a degree of confusion in the literature with rather flawed meta-analyses comparing chalk with cheese, as is sometimes the case, when we look at meta-analytical data. Having this prospective, the randomized trial comparing thermal ablation and surgical resection is welcome.

The patients that they selected had, they say, small size, so the nodule size in the liver would be 3 cm or less. However, [eligible patients] were allowed to have as many as 10 separate nodules, so a significant disease burden.

They powered the trial based on noninferiority — there's a whole separate Medscape video we could do about noninferiority — and they set their hazard ratio at 1.3. That's quite a big margin. They planned to recruit 600 patients, but at a planned interim analysis after around 30 months with 300 patients, they found that they had met their trial endpoints.

Transcript in its entirety can be found by clicking here:
https://www.medscape.com/viewarticle/collision-thermal-ablation-colorectal-liver-metastases-2025a10006le?src=soc_yt