Cryosurgery Freezes and Kills Liver Tumors

Liver cancer has often been seen as a death sentence, but progress in surgical techniques is improving the range of cases that can be treated. Traditional surgery, or resection, removes portions of the cancerous liver. Up to 80% of patients are not considered candidates for resection procedures. The recent addition of cryosurgery to standard surgery techniques expands the number of patients who may benefit from surgical treatment of liver tumors.

Use of cryosurgery to freeze cancerous tissue can make it possible to:

• Destroy tumors deep in the liver without major resection.
• Destroy tumors without significant loss of blood.
• Preserve more of the normal liver tissue.
• Combine resection of one lobe of the liver with localized tumor destruction in another lobe, thus increasing the number of tumors that can be removed.

Sometimes benign tumors are treated with cryosurgery, but not all tumors are appropriate for the procedure. Location of the tumor is a factor in determining which procedures may be used, along with the number and size(s) of tumors. Very large tumors (over 5 centimeters) or a liver containing many tumors, may not be treatable with cryosurgery. However, by combining resection and cryosurgery, more than 10 tumors have been removed in some patients.

Operative Technique
An incision is made in the abdomen beneath the rib cage. Some of the adjoining tissue around the organ is cut so that the liver may be easily manipulated for thorough examination by hand, sight and intraoperative ultrasound, as well as for placement of the cryosurgery probe. These probes vary in size between 3 and 10 millimeters, each with a gold tip and insulated shaft and handle. The probe is connected to a machine that circulates liquid nitrogen at -360 F and allows circulation of heated nitrogen gas to thaw the probe.

The intraoperative ultrasound is a hand-held probe that helps the surgeon identify as many tumors as possible. It is absolutely essential for correctly positioning the cryosurgical probe during surgery. After the abdomen is explored for signs of other tumors, all identified liver tumors are mapped. Once a tumor is identified to be frozen, the ultrasound is used to explore the adjacent organ structures and to find a safe access path for the cryosurgery probe.

The probe is inserted into the center of the tumor and freezing begins. As it progresses, an iceball forms and eventually encompasses the entire tumor plus a one centimeter margin surrounding the tumor. Generally, the maximum size achieved by 15 minutes of freezing with a single probe is about 5 centimeters in diameter. Larger iceballs can be achieved by using multiple probes within a single tumor.

Next the tumor is allowed to partially thaw, and then it is frozen a second time, killing more cancer cells. To remove the cryoprobe from what is now a solid block of tissue, heated nitrogen gas is circulated through the probe. Completely destroyed tumors will degenerate and eventually be absorbed by the body.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.