A new sequential treatment strategy for multiple colorectal liver metastases: Planned incomplete resection and postoperative completion ablation for intentionally-untreated tumors under guidance of cross-sectional imaging.

Abstract Purpose We retrospectively evaluated outcomes of a new sequential treatment strategy for patients with multiple colorectal liver metastases (CLM): planned incomplete resection and postoperative percutaneous completion ablation for intentionally-untreated unresected lesions under cross-sectional imaging guidance. Methods Patients with CLM who underwent curative-intent hepatectomy and ablation during 2007–2018 were analyzed. Complications, local tumor progression (LTP) rates at ablation site(s), and overall survival (OS) estimated using the Kaplan-Meier method were compared between patients who underwent CLM resection and postoperative percutaneous ablation for intentionally-untreated lesions (completion ablation) and patients who underwent CLM resection and concomitant intraoperative CLM ablation under ultrasound guidance. Results Number and largest diameter of CLM and liver resection complexity did not differ significantly between the completion ablation (n = 23) and intraoperative ablation (n = 92) groups. Microwave (versus radiofrequency) ablation was used more frequently in the completion ablation group than in the intraoperative ablation group (61% [14/23] vs. 6% [6/92], P = 0.001). The complication rate after hepatectomy and ablation was significantly lower in the completion ablation group (21% [5/23] versus 48% [44/92], P = 0.033). No death was observed in either group. The 5-year LTP cumulative incidence was significantly lower in the completion ablation group (31.7% versus 62.4%, P = 0.030). The 5-year OS rate did not differ significantly between groups (53%, completion ablation; 42%, intraoperative ablation; P = 0.407). Conclusions Resection and postoperative percutaneous completion ablation under cross-sectional imaging guidance may be a safe and effective treatment pathway in patients with CLM in whom liver resection alone cannot achieve R0 resection.