Thermal ablation of small renal tumors--present status

Thermal ablation of renal tumors is achieved by the delivery of extreme heat or extreme cold directly to the lesion in order to obtain in situ destruction of the malignant cells without having to remove the entire organ. Cryotherapy and radiofrequency ablation are becoming more and more attractive for the treatment of small lesions in select cases. Other types of energy such as microwave, laser and high intensity ultrasound have also been used to destroy kidney lesions but must still be considered in the experimental stage. Cryotherapy and radiofrequency ablation are minimally invasive and have been shown to be safe and effective in treating tumors up to 3 -4 cm in diameter. However, the number of case series is rather limited and follow-up, especially for radiofrequency ablation, is short. Only now are workers beginning to present outcomes after 5 years for cryoablation. Therefore, the long-term oncological efficacy of these ablation techniques remains to be seen. As longer follow-up and greater patient numbers are reported we will get a clearer picture of the true potential of these modalities. Randomized prospective trials would be auspicable. For now, CA and RFA should be limited to few select patients - i.e. patients with comorbidities which render them at high risk for a surgical procedure and possibly patients with genetic conditions such as Von Hippel Lindau disease who will probably develop multiple tumors.