To evaluate long term results for MR-guided LITT for the treatment of colorectal liver metastases.

MR-guided LITT was performed in 839 patients (mean age 61.6 years) with 2506 liver metastases of colorectal cancer between 1993 and 2005. Survival rates were calculated using the Kaplan-Meier method. 33.3% of the lesions were 2 cm or less in diameter (mean applied energy 54.5 KJ, range 8.2-249.7 KJ), 33.3% were between 2 and 3 cm (mean applied energy 94.9 KJ, range 11.6-361.4 KJ), 18.1% were between 3 and 4 cm (mean applied energy 133.45 KJ, range 20.2-452.6 KJ), and 15.6% were larger than 4 cm in maximum diameter (mean applied energy 189.1 KJ, range 10.4-515.0 KJ). 77.6% (n=651) of the patients had 5 liver mets or less and no extrahepatic disease at the time of inclusion and were treated in curative intention. 22.4% (n=188) were treated in palliative intention (patients with more than 5 mets and/or limited extrahepatic disease). The following number of metastases was treated: 1 met in 29% of the patients, 2 mets in 26.5%, 3 mets in 17.8%, 4 mets in 10.6%, 5 mets in 7.5%, and more than 5 mets in 8,6% of the patients.

The mean survival rate for all treated patients, starting the calculation at the date of diagnosis of the metastases which was treated with LITT, was 3.8 years (95% confidence interval: 3.5 - 4.1 years, 1 year survival 93%, 2 year survival 72%, 3 year survival 47%, 5 year survival 24%). Starting the calculation after the first LITT treatment the mean survival was 3.3 years (95% confidence interval: 3.0 – 3.6 years, 1 year survival 93%, 2 year survival 72%, 3 year survival 47%, 5 year survival 24%). The mean survival in the curative group was 4.0 years (95% CI: 3.7 – 4.4 years) and in the palliative group was 2.8 years (95% CI: 2.4 – 3.1 years).

MR-guided LITT yields high local tumor control and survival rates in patients with liver metastases of colorectal carcinoma. LITT appears in surgical candidates superior to resection.