Purpose
To confirm that percutaneous laser-induced thermoablation (pLIT) is a safe and efficient local procedure to obtain complete tumor shrinkage whenever surgical resection of liver metastases from colorectal cancer is not possible. To demonstrate that even if thermoablation is obtained by pLIT patients treated for a small dominant lesion (less than 3 cm) experience a better outcome.
Material and methods
Whenever surgical resection of liver metastases from colorectal cancer is not possible, thermal ablation is a mini-invasive local treatment that can be considered as an alternative approach. Complete thermal ablation can be achieved by laser treatment. When thermoablation is obtained by radiofrequency, patients treated for a small dominant lesion (less than 3 cm) experience a better outcome. This evidence is less clear when pLIT is used.
Results
30 patients (22 with a single lesion, 8 with up to three metastasis) have been consecutively treated. Maximum diameter of the dominant lesion was smaller than 3 cm in 20 pts and larger than 3 cm in ten. With previous mild sedation and local anaesthesia, optical fibers were inserted directly into the tumor with echo-guided percutaneous needle placement. Each optical fiber has been connected to a neodymium:yttrium-aluminium-garnet (ND:YAG) laser, which delivers concentrated light at a wave-length of 1064 nm, with a 5-Watt power and a 1800-Joule energy per single fiber. A minimum of two and a maximum of four needles were used, with a 5 to 8 mm distance from one needle to another. All the patients tolerated LIT procedure well, without major complications. Post-treatment CT-scan demonstrated complete thermonecrosis in 39 out of 44 (87%) of the treated lesions, and almost complete in the rest. Local failure was reported in 12% of the lesions at six-month follow-up. The median Kaplan-Meier survival for all patients was 607 days, with survival rate of 82% at one year and 55% at three years. Patients treated for a smaller dominant lesion had a significantly better survival then the others (850 vs 420 days, p=0.04, Logrank).
Conclusion
pLIT permitted in most cases a complete ablation of liver metastases with a high local tumor control rate and a low complication rate. Patients with a smaller dominant lesion do best after pLIT procedure. Local treatment coupled with systemic chemotherapy offers a chance of prolonged survival in patients non amenable to hepatic surgery.