Purpose: Thermal ablation is widely recognized as the standard of care for small-size unresectable colorectal liver metastases (CRLM). For larger CRLM safety, local control and overall efficacy are not well established and insufficiently validated. The purpose of this comparative series was to analyze outcomes for intermediate-size versus small-size CRLM. Material and methods: Patients treated with thermal ablation between December 2000 and November 2021 for small-size and intermediate-size CRLM were included. The primary endpoints were complication rate and local control (LC). Secondary endpoints included local tumor progression-free survival (LTPFS) and overall survival (OS). Results: In total, 59 patients were included in the intermediate-size (3–5 cm) group and 221 in the small-size (0–3 cm) group. Complications were not significantly different between the two groups (p = 0.546). No significant difference between the groups was found in an overall comparison of OS (HR 1.339; 95% CI 0.824–2.176; p = 0.239). LTPFS (HR 3.388; p < 0.001) and LC (HR 3.744; p = 0.004) were superior in the small-size group. Nevertheless, the 1-, 3-, and 5-year LC for intermediate-size CRLM was still 93.9%, 85.4%, and 81.5%, and technical efficacy improved over time. Conclusions: Thermal ablation for intermediate-size unresectable CRLM is safe and induces long-term LC in the vast majority. The results of the COLLISION-XL trial (unresectable colorectal liver metastases: stereotactic body radiotherapy versus microwave ablation—a phase II randomized controlled trial for CRLM 3–5 cm) are required to provide further clarification of the role of local ablative methods for intermediate-size unresectable CRLM.

With the rapidly evolving field of image-guided tumor ablation, there is an increasing demand and need for tools to optimize treatment success. Known factors affecting the success of (non-)thermal liver ablation procedures are the ability to optimize tumor and surrounding critical structure visualization, ablation applicator targeting, and ablation zone confirmation. A recent study showed superior local tumor progression-free survival and local control outcomes when using transcatheter computed tomography hepatic angiography (CTHA) guidance in percutaneous liver ablation procedures. This pictorial review provides eight clinical cases from three institutions, MD Anderson (Houston, TX, USA), Gustave Roussy (Paris, France), and Amsterdam UMC (Amsterdam, The Netherlands), with the intent to demonstrate the added value of real-time CTHA guided tumor ablation for primary liver tumors and liver-only metastatic disease. The clinical illustrations highlight the ability to improve the detectability of the initial target liver tumor(s) and identify surrounding critical vascular structures, detect ‘vanished’ and/or additional tumors intraprocedurally, differentiate local tumor progression from non-enhancing scar tissue, and promptly detect and respond to iatrogenic hemorrhagic events. Although at the cost of adding a minor but safe intervention, CTHA-guided liver tumor ablation minimizes complications of the actual ablation procedure, reduces the number of repeat ablations, and improves the oncological outcome of patients with liver malignancies. Therefore, we recommend adopting CTHA as a potential quality-improving guiding method within the (inter)national standards of practice.

Purpose: Mucinous cystic neoplasms of the liver (MCN-L) are hepatic cysts with a low malignant potential. The recent European Association for the Study of the Liver (EASL) guidelines provide guidance on the imaging features and surgical management of MCN-L, yet are hampered by a lack of studies adhering to the revised World Health Organization (WHO) criteria. This study attempted to validate the new 2022 EASL-guidelines in a retrospective cohort study of patients who underwent surgery for suspected MCN-L. Methods: Patients undergoing surgery for suspected MCN-L in a single center between 2010 and 2020 were included. Imaging features were assessed according to the EASL guidelines and were compared to final pathological diagnoses, according to the WHO criteria. Results: In total, 35 patients were included. In three patients, there were no worrisome imaging features, yet final pathological diagnosis showed MCN-L. Contrarily, six patients with worrisome imaging features did not have MCN-L. Five patients were diagnosed with MCN-L on final pathology. The sensitivity of the EASL-guidelines for the diagnosis of MCN-L was 40% (95%CI: 5.3–85%) and the specificity was 80% (95% CI: 61–92%). Conclusion: Although the new EASL-guidelines provide some guidance, they could not reliably distinguish MCN-L from other cysts in our series. Thus, preoperative diagnosis of MCN-L remains challenging and we should be careful in selecting surgical strategies based on these criteria.

Background: The simultaneous presence of colorectal liver metastases (CRLMs) and extrahepatic metastases in patients with colorectal cancer (CRC) can be considered a relative contraindication for local treatment with curative intent. This study aims to assess the survival outcomes of patients with CRLMs and extrahepatic metastases after comprehensive local treatment of all metastatic sites. Methods: Patients with CRLMs who received local treatment of all metastatic sites were extracted from the prospective AmCORE registry database and subdivided into two groups: CRLM only vs. CRLM and extrahepatic metastasis. To address potential confounders, multivariate analysis was performed. The primary endpoint was overall survival (OS). Results: In total, 881 patients with CRLM only and 60 with CRLM and extrahepatic disease were included, and the median OS was 55.7 months vs. 42.7 months, respectively. Though OS was significantly lower in patients with concomitant extrahepatic metastases (HR 1.477; 95% CI 1.029–2.121; p = 0.033), the survival curve plateaued after 6.2 years. Extrahepatic manifestations were pulmonary (43.3%), peritoneal (16.7%) and non-regional lymph node metastases (10.0%). In patients with pulmonary and non-regional lymph node metastases, OS did not significantly differ from patients with CRLM-only disease; concomitant peritoneal metastases showed an inferior OS (HR 1.976; 95% CI 1.017–3.841, p = 0.041). Conclusions: In this comparative series, OS was inferior for patients with multi-organ metastatic CRC versus patients with CRLMs alone. Nonetheless, the long-term survival curve plateau seemed to justify local treatment in a subset of patients with multi-organ metastatic CRC, especially for patients with CRLMs and pulmonary or lymph node metastases.

Purpose: Surgical resection has been the gold standard for colorectal liver metastases (CRLM) for decades. In recent years, thermal ablation has emerged as a first-line treatment option for small-size CRLM, while for intermediate-size lesions (3–5 cm), it is reserved for patients with unresectable disease. In this setting, thermal ablation has proven safe and effective, achieving durable local control (LC) in the majority of patients. This retrospective study compares oncological outcomes of thermal ablation versus surgical resection of intermediate-size (3–5 cm) CRLM. Material and methods: Patients treated with thermal ablation or surgical resection for intermediate-size CRLM between 2000 and 2025 were included. Baseline per-patient and per-procedure characteristics were compared across three groups: thermal ablation, surgical resection, and combined treatment. Per tumor characteristics were compared between thermal ablation and surgical resection. Primary outcomes included local tumor progression-free survival (LTPFS) and complication rates. Secondary outcomes were OS, distant progression-free survival (DPFS), LC, and length of hospital stay. Survival outcomes were analyzed using the Kaplan–Meier method; additionally, LTPFS was assessed using Cox proportional hazards regression models, with multivariable analyses performed to adjust for potential confounders. Results: A total of 320 patients with 448 metastases were included: 135 patients underwent thermal ablation, 156 underwent surgical resection, and 29 received combined treatment. LTPFS per tumor was significantly higher in the surgical resection group (HR 1.86, 95% CI 1.24–2.81, p = 0.0025), however, LC per tumor did not significantly differ amongst groups (HR 1.48, 95% CI 0.70–3.11, p = 0.307). Complication rates were significantly higher after resection (p < 0.001). OS and DPFS did not differ significantly between the three groups (p = 0.08 and p = 0.084). OS comparing only thermal ablation and resection was significantly lower in the thermal ablation group. Median hospital stay was 3, 5, and 7 days for the ablation, resection, and combined groups, respectively (p < 0.001). Conclusions: Thermal ablation offers a safe alternative to surgical resection for selected patients with intermediate-size (3–5 cm) CRLM, with higher treatment-site recurrence rates. With the option of repeat ablation, comparable local tumor control can be achieved. Improvements in local control with both modalities over time support the need for a prospective clinical trial.