KIDNEY CANCER CRYOTHERAPY
Cryotherapy, also called cryoablation and cryosurgery, refers to the use of very cold temperatures to treat disease and is a mainstay therapy for a wide variety of conditions. It is a well-established technology for the treatment of many benign and malignant tumors and lesions, and is also one of the oldest documented forms of medical treatment—the Egyptians used cold to treat inflammation and injuries as early as 2500BC.
Cryotherapy is indicated as a treatment for cortical or peripheral lesions, for solid lesions less than 4cm, and for patients with a single kidney or poor kidney function. Kidney cancer ablation eradicates the cancerous tissue by freezing it. Very precise targeting and control of the energy allows for efficient destruction of tumor cells while leaving healthy kidney tissue intact and functional.
To freeze the cancer, special thin probes called cryoablation needles are placed into the tumor. 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 -100º Celsius. This produces an iceball of predictable size and shape around the needle. This iceball engulfs the tumor, killing the cancerous cells as well as a small margin of surrounding tissue while sparing healthy kidney structures. A double freeze-thaw cycle is favored, since studies suggest that consistently larger areas of cell death are achieved with a double rather than single freeze-thaw cycle. Ultra-thin thermal sensors may also be placed at the margin of the tumor to monitor tissue temperature and help ensure that the entire tumor is destroyed.
Renal cancer ablation using cryotherapy can be performed through several flexible approaches, so treatment can be customized by the physician to accommodate the patient’s general health as well as the size and location of the tumor.
Renal cryosurgery can be performed during traditional open surgery, although this approach is rarely used today by experienced kidney surgeons performing kidney cryoablation. Open surgery is more painful, has a longer recovery time and generally results in more complications than minimally invasive surgery. If an open procedure is chosen, it is always performed under general anesthesia and it is recommended that intraoperative ultrasound be utilized as guidance for cryoablation needle placement and positioning.
Laparoscopic-guided cryosurgery on the kidney is a 1 to 3 hour procedure and is almost always performed under general anesthesia. Making 3-4 small incisions, standard laparoscopic technique is used to visualize the kidney, and a laparoscopic ultrasound probe is used to monitor the percutaneous placement of the cryoablation needle(s) and thermal sensors into the tumor. Additionally, the ultrasound probe is used to monitor the tumor and iceball during the double freeze-thaw process, ensuring destruction of the entire tumor as well as the desired margin of surrounding tissue.
Another minimally invasive approach is percutaneous ablation. With percutaneous access, no incisions are made. The patient is positioned in the CT or MRI scanner. The cryoablation needlesand thermal sensors are inserted through the skin and positioned in the tumor under the guidance of CT, MRI or Ultrasound and the entire procedure is monitored using CT or MRI. Image-guided percutaneous cryoablation is usually performed under general anesthesia, but can be done under light sedation. Percutaneous cryoablation is the least invasive intervention that can be performed for kidney cancer.
There are many benefits to kidney cancer treatment via minimally invasive kidney cryotherapy. To learn more about the advantages of renal cancer cryoablation, see the section entitled The Benefits of Kidney Cryotherapy.