Is Stereotactic Microwave Ablation of Resectable Colorectal Liver Metastasis an Alternative for Liver Resection in Covid19 Pandemic

Purpose: Recent studies showed no difference in overall survival between microwave ablation (MWA) and resection of colorectal liver metastasis (CRLM) ≤ 3cm. Percutaneous MWA (pMWA) under CT guidance is less invasive than surgical ablation but less accurate due to “free-hand” puncture, resulting in higher rates of incomplete ablation and local recurrence. Moreover, lesions in segments 1, 2, 4A, 7, 8 are difficult to reach by “free-hand” approach. Stereotactic navigation allows accurate puncture in all liver segments. Covid19 pandemic restricted hospital capacity in Belgium. To avoid unacceptable delay in oncologic liver resections, stereotactic pMWA was introduced in our hospital. Methods: From March 2020 to February 2021, all patients with resectable CRLM ≤ 3 cm were treated by pMWA with stereotactic technology (Cascination®). Segmental localization, postoperative morbidity (Clavien-Dindo), incomplete ablation (MRI at 2 months), hospital stay, ICU stay and OR time were recorded. These latter data were compared with a cohort of patients treated for CRLM ≤ 3cm treated by liver resection in 2019. Results: 25 patients with 41 liver CRLM were included. Median age was 69y (52-85y). 25/41 (61%) tumors were in liver segments 1, 2, 4A, 7 or 8. 25/26 patients had no complications (Clavien 0 or 1). 1 patient developed biliary stricture and was treated by endoscopic stenting (Clavien 3A). 4/41 (9,7%) of metastasis showed incomplete ablation on MRI. These were treated with re-ablation resulting in complete ablation after 2 months. Hospital stay was 1 day in 23/25 patients, 3.7 days shorter than after resection. No ICU stay was recorded. OR time per patient was reduced by 3.6h compared to resection. Conclusion: Covid19 pandemic reduced hospital capacity. Introducing pMWA allows reducing hospital stay, ICU stay, OR time and postoperative complication rate. Not only this avoids the dilemma whether to treat highly affected Covid19 patients or to perform high risk liver surgery, but it has the potential to reduce the risk of Covid19-related morbidity & mortality after liver surgery. pMWA with stereotactic navigation allows precise puncture in any liver segment, with low rates of incomplete ablation and equivalent oncologic results in CRLM ≤ 3 cm. Moreover, it can be continued when hospital capacities are reduced.