Radiofrequency ablation of liver metastases from colorectal cancer
Objective: To assess the effectiveness of radiofrequency ablation (RFA) of liver metastases from colorectal cancer (CRC).
Methods: 92 patients with 148 lesions (age 31–81, tumor size 0.5–11.0cm) were treated with monopolar RFA with perfused applicators and 29 patients with 53 metastases (age 40–80, size 2.0–11.5cm) were treated with multipolar RFA using 3 bipolar internally-cooled applicators. The effectiveness was assessed with contrast-enhanced ultrasound, CT, and cytological examination. Patients were followed up for 1–39 months (mean 14).
Results: With monopolar RFA complete destruction was achieved in 87.9%(87/99) of lesions ≤3.0cm, in 56.8%(21/37) of lesions sized 3.1–5.0cm and in 16.7%(2/12) of lesions >5.0cm, depending significantly on the size, location in risky zone and amount of RF energy per volume. Major complications occurred in 7.6% of the patients. Local tumor progression (LTP=recurrence) was observed in 33.6% of the lesions, depending on the size and additional chemotherapy. In 75.7% of recurred lesions new RFA was performed with 46% effectiveness. 29.3% of the patients developed new liver metastases and in 55.6% of them new local ablation was possible. With multipolar RFA complete destruction was accomplished in 100%(6/6) of the small, 84%(21/25) of medium-sized and in 31.8%(7/22) of large lesions, depending on the size and RFE amount. Major complications occurred in 6.9%. LTP was observed in 23.5%.
Conclusion: The effectiveness of RFA in CRC metastases depends on the tumor size and amount of RFE per volume. Multipolar RFA is preferable in lesions >3.0cm. Combination with chemotherapy could additionally prolong survival.