Patients undergo placement of an ablation electrode percutaneously into the tumor(s) by CT scan, MRI, or ultrasound guidance. Patients then undergo percutaneous radiofrequency ablation (RFA) directly to the tumor(s) for 12 minutes. Patients undergo CT scan of the liver within 1 week after RFA treatment and then every 3 months for up to 18 months. Patients with residual or recurrent intrahepatic tumor(s) detectable on the 3-month or subsequent CT scan undergo repeat RFA as is technically feasible and clinically indicated for up to 15 months after initial RFA treatment.