Percutaneous MR imaging-guided laser-induced thermotherapy of hepatic metastases

Background: Many primary tumors may cause liver metastases, which are gener ally treated with surgical resection and/or chemotherapy. After resection o f liver metastases in patients with colorectal carcinoma, 5-year survival r ates are achieved in 25-38%, and two-thirds of patients will experience rec urrent metastases. We examined percutaneous, minimally invasive, laser-indu ced thermotherapy (LITT) as an alternative outpatient procedure. Local tumo r control rate and survival data were analyzed prospectively. Methods: Between June 1993 and August 2000, 7148 laser applications were pe rformed in 1981 lesions in 705 consecutive patients and 1653 treatment sess ions. The complications of the procedure were evaluated by clinical examina tion and magnetic resonance imaging (MRI) and computed tomography. Local tu mor control was evaluated by plain and contrast-enhanced follow-up MRI usin g T1- and T2-weighted spin-echo and gradient-echo sequences every 3 months after treatment. Cumulative survival times were calculated using the Kaplan -Meier method. Results: The overall rate of complications and side effects was 7.5%. The r ate of clinically relevant complications was 1.3%. Local tumor control rate after 3 months was 99.3%; 6 months after laser treatment, plain and contra st-enhanced MRI documented a local tumor control rate of 97.9%. In patients treated with MR-guided LITT for unresectable colorectal liver metastases, the mean survival was 41.8 months (95% confidence interval = 37.3-46.4 mont hs). The 1-year survival rate was 93%, the 2-year survival rate was 74%, th e 3-year survival rate was 50%, and the 5-year survival was 30%. In patient s treated with LITT for liver metastases from breast cancer, the mean survi val was 4.3 years (95% confidence interval = 3.6-5.0 years). Conclusion: In patients with liver metastases, local tumor destruction usin g minimally invasive, percutaneous LITT under local anesthesia results in i mproved clinical outcomes and survival rates and can be a potential alterna tive to surgical resection.