Martijn Meijerink, MD, PhD, Amsterdam UMC, Amsterdam, Netherlands, shares results from the multicenter, phase 3, noninferiority COLLISION study evaluating surgery vs thermal ablation for small-size colorectal liver metastases.

Dr Meijerink concluded, “if the standard of care shifts from surgical resection to thermal ablation for small colorectal liver met[astases], it will likely would reduce the mortality and morbidity, it shorten hospital stay, improve quality of life…and this does not go at the cost of more local recurrences or a decreased long-term survival.”

Transcript:

My name is Martijn Meijering, I'm a professor of interventional radiology from the Amsterdam University Medical Center. I’m here at ASCO 2024 to present the final results of the international, randomized, controlled phase 3 trial called COLLISION.

The COLLISION trial is a trial comparing surgical resection to thermal ablation for small-size colorectal liver metastases. This was a non-inferiority trial, so the idea was to assess whether surgical resection or thermal ablation were equal regarding overall survival and progression free survival. But perhaps, and this was based on retrospective data, thermal ablation was associated with a lower number of adverse events. Eventually we recruited 300 patients, 4 were excluded after randomization for not having the disease assessed. So, there were 148 patients in both treatment arms. Surgical resection meant that all the small-size tumors were resected in those patients, and if randomized to ablation it meant all the tumors were ablated using the most modern techniques, both for surgery and thermal ablation.

We originally planned to have 600 patients in the study, but there was a pre-planned interim analysis after having recruited 300 patients, and there were stopping rules for futility and for early benefit. Early benefit meant if there was a significantly lower number of adverse events in the experimental arm, and if the local control was either equal or superior in the experimental arm, regarding the primary endpoint overall survival. There was a conditional probability to eventually prove non-inferiority of over 90% that meant that we had to stop the trial for early benefit and that was the case. We had a significantly lower number of adverse events in the experimental arm of thermal ablation. Mortality was 3 in the resection arm, 0 in the ablation arm.

Also the lower grade complications were more commonly seen with surgical resection when compared to thermal ablation. Hospital stay was significantly shorter with thermal ablation and thermal ablation did not seem to affect local tumor progression-free survival or the distant progression-free survival and it did not affect the primary end point of overall survival.

Interestingly, there was a superior local control, and this end point means allowing repeat treatments in the experimental arm of thermal ablation. Somehow, when preferring thermal ablation over surgical resection, the number of completed eradications eventually achieved seemed to be superior to the thermal ablation arm.

We concluded that if the standard of care shifts from surgical resection to thermal ablation for small colorectal liver met[astases], it will likely reduce the mortality and morbidity. It will shorten hospital stay, improve quality of life, and presumably cost-effectiveness — we have to do that analysis in the future— and this does not go at the cost of more local recurrences or a decreased long-term overall survival.

Source:

Meijerink MR, Van der Lei S, Dijkstra M, et al. Surgery versus thermal ablation for small-size colorectal liver metastases (COLLISION): An international, multicenter, phase III randomized controlled trial. Presented at the 2024 ASCO Annual Meeting. May 31-June 4, 2024; Chicago, IL. Abstract #LBA3501