P-230 Is stereotactic microwave ablation of resectable colorectal liver metastasis an alternative for liver resection in the Covid-19 pandemic?

Chapelle, T.; Op de Beeck, B.; Bracke, B.; Niekel, M.; Roeyen, G.; Hartman, V.; Spinhoven, M.; Ysebaert, D.

Background: Liver resection for resectable colorectal liver metastasis is still considered the standard local therapy. Recent studies showed no difference in overall survival between microwave ablation and resection of liver metastasis with a diameter less than 3 cm. Ablation by percutaneous approach and under CT guidance is considered less invasive than open or laparoscopic resection or ablation. On the other hand, percutaneous ablation by “free-hand” puncture is considered less accurate, potentially resulting in higher incomplete ablation and local recurrence rates. Moreover, lesions in the upper liver segments 2, 4A, 7, 8 and in segment 1 are very difficult to reach by “free-hand” approach. Stereotactic navigation technology allows very accurate puncture and can easily reach liver lesions in all liver segments. The start of the Covid-19 pandemic in March 2020 resulted in strict capacity limitations in OR facilities, hospital beds, and ICU beds in Belgium. To avoid unacceptable delay in oncologic liver resections, stereotactic microwave ablation was introduced in our hospital. Methods: From March 2020 to January 2021, all patients with resectable colorectal liver metastasis ≤ 3 cm were treated by percutaneous ablation under CT guidance with stereotactic technology (Cascination®). Segmental localization of the liver tumors and postoperative complication rate according Clavien-Dindo classification were registered. Incomplete ablation was estimated by MRI 2 months after treatment. We recorded hospital stay, ICU stay and OR time. These data were compared with a cohort of patients treated for colorectal liver metastasis ≤ 3cm by liver resection in 2019. Results: 20 patients with 36 liver colorectal metastasis were included. Median age was 69y (52-84y). 21/36 (58%) tumors were localized in liver segments 1, 2, 4A, 7 or 8. 19/20 patients had no complications (Clavien 0 or 1). 1 patient developed biliary stricture and was treated by endoscopic stenting (Clavien 3A). No postoperative mortality was recorded. 3/36 (8,3%) metastasis showed incomplete ablation on MRI. All were treated with re-ablation with complete ablation after 2 months. Hospital stay was 1 overnight stay in 19/20 patients, shortening hospital stay by 3.7 days per patient compared to the resection cohort. No ICU stay was needed after percutaneous ablation. OR time was reduced by 3.6h per patient. Conclusions: The Covid-19 pandemic reduced hospital and ICU capacity drastically. It can lead to a dilemma whether to treat highly affected Covid-19 patients or to perform high-risk oncologic surgery. Introducing percutaneous ablation allows the reduction of hospital stay, ICU stay, OR time, and postoperative complication rate. Not only does this reduce the need for the dilemma of which patient can be treated, but it has the potential to reduce the risk of Covid-19-related morbidity and mortality after high-risk oncologic surgery. Introducing percutaneous ablation with stereotactic navigation allows easy local treatment in any liver segment. Moreover, very precise needle positioning resulted in accurate ablation areas, with low rates of incomplete ablation and need for re-ablation. Finally, this minimally invasive approach offers appropriate local treatment with equivalent oncologic results in resectable colorectal liver metastasis ≤ 3 cm. It can be continued in temporarily reduced hospital capacities. Legal entity responsible for the study: The author. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.