The purpose of this study is to determine if the, MR guided, laser interstitial thermal therapy (LITT) treatment technique can be safety and efficiently used for the human liver metastasis

This new "minimally invasive" technique has been tested so far, with success, on animal brain and prostate tumors. LITT has also tested with success by other teams for the treatment of liver metastasis.

The main purpose of this study is to determine if the Visualase, MR guided, laser interstitial thermal therapy device can be safely and efficiently used for the treatment of human liver metastasis originating from the colon and rectal primary tumors.

As secondary objectives for this clinical study is to explore the tolerance of the treatment and its contra indications.

The clinical trial will include a statistical sample of 25 patients and will run over a period of 24 months. The inclusion period will be of 12 months and the patients will be followed up during a period of 7 days after the intervention.

The clinical trial will be performed at the Cochin University Hospital of Paris and the patients will be coming from the oncology / surgery departments of the hospital.

The patients recruited for this study are those who developed several liver metastasis and are planned for the a surgical resection for part of the liver (where metastasis are located). Prior to the surgical resection, a LITT procedure will be performed on one of the metastasis. After the surgical resection histological analysis will be elaborated to compare the real necrosis volume created by the LITT procedure to the expected predicted volume.

Inclusion Criteria:

• Patients 18 years of age or older
• Patients with liver metastasis, originating from colon and liver cancer and proved by histological analysis
• Patient that are scheduled for a surgical resection of part of the liver,
• Patient having a liver metastasis, originating from colon and rectal cancer, smaller or equal to 3 cm
• Patients having the liver metastasis at a distance of at least 1 cm or from the hepatic capsule or/and from a vascular structure

Exclusion Criteria:

• Patients younger than 18 years old
• Patients presenting contra indication for MRI studies
• Patient presenting contra indication to liver surgery
• Patients who already had other interstitial treatment on the targeted lesion