KIDNEY CRYOABLATION
TREATMENT

a. Overview

Cryoablation is a well-established technology for the treatment of many benign and malignant tumours and lesions. Kidney cancer cryoablation destroys the cancerous tissue by freezing the cancer cells. Very precise needle placement and control of the energy allow for efficient destruction of tumour cells while leaving healthy kidney tissue intact and functional.

b. Cryoablation Procedure

To freeze the cancer, special thin cryoablation needles are inserted into the site targeted for ablation. Argon gas is delivered under pressure into a small chamber inside the tip of the needle where it expands and cools, reaching a temperature well below -100° Celsius. This produces an iceball of predictable size and shape around the needle. This iceball engulfs the tumour, killing the cancerous cells as well as a small margin of surrounding tissue while sparing healthy kidney structures.

Ultra-thin Multi-Point Thermal Sensors may also be placed at the periphery of the target tissue to ensure ablative
temperatures are reached or to monitor temperature near adjacent critical structures.

c. Cryoablation Approaches

A couple of approaches can be used to perform renal cancer cryoablation, so the physician can customise the treatment to accommodate the patient’s general health as well as the size and location of the tumour. A minimally invasive approach, rather than an open surgical approach, is usually preferred.

Percutaneous Approach
The minimally invasive approach most frequently chosen is percutaneous ablation. With percutaneous access, no incisions are made. The patient is positioned in a CT (computerised tomography) or MRI (magnetic resonance imaging) scanner. The cryoablation needles and thermal sensors are inserted through the skin and positioned in the target tissue under the image guidance of CT, MRI or ultrasound and the entire procedure is monitored using CT or MRI. Image-guided percutaneous cryoablation may be performed under conscious sedation, local anesthesia, or general anesthesia.

Laparoscopic Approach
Laparoscopic-guided kidney cryoablation, also a minimally invasive approach, is conducted using 3-4 small incisions through which instruments are inserted. A laparoscopic ultrasound probe is inserted through one of these incisions to send images to a screen so the physician can visualise the kidney, appropriately position the cryoablation needles, observe the iceball formation and ensure tissue destruction. Laparoscopic cryoablation is almost always performed under general anesthesia.

Open Surgery
Renal cryoablation can also be performed during traditional open surgery, although this approach is rarely used today. 

Image courtesy of Dr. Thierry de Baere, Institute Gustave Roussy, Villejuif, France

...Cryoablation results in fewer retreatments, improved local tumour control and may be associated with a lower risk of matastatic progression compared to RFA... Kunkle DA & Uzzo RG. 20081

Kunkle DA & Uzzo RG. 20081

References
  1. Kunkle DA, Uzzo RG. Cancer 2008; 113(10): 2671-80