Therapeutic Efficacy and Safety of Ultrasound-Guided Microwave Ablation for Hepatic Metastatic Nodules

The liver is one of the most common organs where cancer cells spread (metastasize) from other parts of the body, especially from gastrointestinal cancers such as colorectal cancer. While surgical removal of liver tumors has traditionally been the standard treatment, most patients are not candidates for surgery due to tumor location, number of lesions, or underlying liver function. For these individuals, minimally invasive local therapies such as microwave ablation (MWA) provide an alternative approach to eradicate tumor tissue while preserving healthy liver parenchyma. Microwave ablation delivers localized high-frequency electromagnetic energy through a thin needle antenna placed percutaneously into the liver tumor. The generated heat induces rapid coagulative necrosis, destroying cancer cells within the target area. In this study, real-time ultrasound combined with CT image-fusion navigation is used to precisely position the ablation antenna within each nodule. The primary purpose of this study is to assess the therapeutic efficacy and safety of ultrasound-guided percutaneous microwave ablation for patients with liver metastases. Participants receive microwave ablation for their target liver tumors and are evaluated with contrast-enhanced CT or MRI at 1 month post-procedure to determine the rate of complete tumor ablation. Patients are then monitored longitudinally at 3, 6, 9, and 12 months to evaluate safety and check for local tumor recurrence.

Inclusion Criteria: * Adult patients aged 18 years or older. * Proven clinical and imaging diagnosis of hepatic metastatic nodules referred for percutaneous microwave ablation. * Single hepatic nodule with a maximum diameter of ≤4 cm, or up to 3 nodules with the maximum diameter of the largest target nodule ≤3 cm. * Target hepatic metastatic nodules clearly visible and acoustically accessible via conventional transabdominal ultrasound. * Voluntary provision of written informed consent prior to study enrollment. Exclusion Criteria: * Extensive, diffuse, or multifocal bilobar hepatic metastases (\>3 nodules) or massive extrahepatic disease burden. * Severe uncorrected coagulopathy or bleeding diathesis (INR \> 1.5 or baseline platelet count \< 50,000/µL). * General contraindications for percutaneous microwave ablation. * Poor acoustic window preventing adequate real-time ultrasound visualization and needle guidance. * Pregnant or lactating women.