Observation of the clinical use of the Emprint Microwave Ablation System for the ablation of Liver Metastases of Colorectal Adenocarcinoma.

The CIRSE Emprint Microwave Ablation Registry (CIEMAR) is collecting real-life data on the microwave ablation (MWA) of colorectal liver metastatic disease using the Emprint Microwave Ablation System (full study duration) or Emprint HP Microwave Ablation System (from 2021 onwards).

CIEMAR is a prospective, single-arm, multi-centre observational (non-interventional) study with the objective to observe the "real-life" use of MWA in Europe. The study is observing the use of the Emprint or Emprint HP Microwave Ablation System and all patients included in CIEMAR are receiving treatment with this device as their standard care for CRLM.

Primary endpoint: local tumour control in liver at 12 months after MWA on a per lesion basis

Secondary endpoints: Safety; Overall survival; Overall disease-free survival; Hepatic disease-free survival; Time to untreatable progression by thermal ablation; Systemic cancer therapy vacation; Quality of life; Adverse events and toxicity

In order to measure changes in the quality of life of enrolled patients at different moments in time before and after treatment with MWA, CIEMAR is collecting quality of life data using the EORTC QLQ-C30 questionnaire. Filling out the quality-of-life questionnaire is entirely voluntary for the patient. The patient will be offered to fill out the questionnaire in his/her mother tongue.

The site and patient recruitment is complete with 500 patients from 30 sites across 11 European countries. The registry is currently collecting follow-up data (until January 2026).

Inclusion Criteria:

• 18 years or older
• Proven colorectal liver metastases either histologically proven or diagnosed by imaging in a patient with known colorectal cancer
• Treated with the Emprint or Emprint HP Microwave ablation system
• Patient referred to MWA by a multidisciplinary tumour board
• Signed informed consent form
• Intention to completely treat (ablation, resection, SBRT) all visible disease within 8 weeks
• Maximum number of 9 total liver lesions
• All liver lesions must be local treatment-naive
• Maximum diameter of the largest liver lesion treated with MWA must not exceed 3cm
• Maximum diameter of lesions treated surgically may exceed this limitation
• Maximum number of 5 lung nodules eligible to be treated
• Patients may receive simultaneous liver resection and microwave ablation
• Patients may have received previous systemic therapy
• Patients must not have received surgical resection or thermal ablation for other liver lesions in the last 3 months before inclusion
• Patients treated with a liver-first approach may be included if treatment of the primary tumour is planned
• If applicable: complete response of treated rectal tumour proven by imaging

Exclusion Criteria:

• Life expectancy less than 6 months (palliative treatment)
• Extrahepatic metastases with the exception of a maximum of 5 lung nodules
• Ongoing infection (viral/bacterial)
• Patients receiving simultaneous bowel surgery and microwave ablation
• Patients receiving simultaneous IRE, RFA, SBRT, Cryoablation, HIFU or other local treatment than resection
• Pregnancy
• Patients with liver metastases that cannot be completely and safely treated
• Active cancers other than CRC
• Non-resected primary colon cancer
• Advanced liver disease or evidence of liver insufficiency

Patients with colorectal adenocarcinoma and liver-only or liver-dominant metastatic disease