The Evolving Role of Minimally Invasive Management in CRLM: Resection versus Microwave Ablation. A Multicenter Italian Study

Background: Colorectal liver metastases (CRLM) represent a major cause of mortality among patients with colorectal cancer. While liver resection remains the standard treatment for resectable disease, recent evidence from studies such as the MAVERRIC and COLLISION trials has supported the role of microwave ablation (MWA) as a valid alternative for selected patients with small CRLM. In parallel, Textbook Outcome (TO) has emerged as a composite measure of perioperative quality, providing a more comprehensive assessment than conventional surgical endpoints. Aim: To compare perioperative and oncological outcomes of laparoscopic liver resection (LLR) and MWA in patients with CRLM ≤3 cm, focusing on TO achievement, recurrence patterns, overall survival (OS), disease-free survival (DFS), and survival after recurrence (SAR). Materials and Methods: A multicenter retrospective study was conducted including patients undergoing liver-directed treatment for CRLM ≤3 cm at three Italian tertiary referral centres. Patients were divided according to treatment strategy (LLR or MWA). Demographic, clinical, pathological, and oncological data were collected. Oncological risk was assessed using the Fong Clinical Risk Score and Tumor Burden Score (TBS). Survival analyses were performed using the Kaplan–Meier method and Cox proportional hazards regression models. Results: The study included 198 patients, of whom 89 underwent MWA and 109 underwent LLR. Patients treated with MWA presented a less favourable baseline profile, including more frequent previous liver-directed treatments (46% vs. 17%, p < 0.001), multiple metastases (65% vs. 41%, p < 0.001), bilobar disease (40% vs. 22%, p = 0.007), and AJCC stage IV tumours (56% vs. 36%, p = 0.027). Despite these characteristics, TO was achieved more frequently after MWA than after LLR (79% vs. 65%, p = 0.037). MWA was associated with shorter operative time (110 vs. 255 min, p < 0.001), lower blood loss (0 vs. 100 mL, p < 0.001), shorter hospital stay (3 vs. 5 days, p < 0.001), and fewer severe postoperative complications (0% vs. 11%, p = 0.006). Conversely, liver resection was associated with lower recurrence rates (52% vs. 90%, p < 0.001), longer OS (35 vs. 25 months, p = 0.025), and longer SAR (29.5 vs. 22 months, p = 0.030). Recurrence patterns were similar between groups, with the liver representing the predominant site of first recurrence. TO achievement was associated with significantly longer DFS (5 vs. 2 months, p < 0.001). Conclusions: MWA was associated with higher TO rates and superior perioperative outcomes despite being performed in patients with greater comorbidity and tumour burden. However, liver resection remained associated with better long-term oncological outcomes, including lower recurrence rates, longer OS, and longer SAR. The poorer oncological outcomes observed after MWA are likely influenced by differences in baseline disease characteristics and tumour biology between treatment groups. These findings support a tailored multidisciplinary approach in which both MWA and liver resection represent valuable treatment options for selected patients with CRLM ≤3 cm, while highlighting the potential prognostic value of TO beyond traditional perioperative endpoints.