Cryotherapy/ Cryosurgery

Patient Selection Criteria

Candidates for cryosurgery are patients who are considered unresectable (inoperable), but have no evidence of disease outside the liver. However, it must be expected that the liver lesions can be completely destroyed by cryosurgery alone or in combination with resection, as cryotherapy is not an appropriate palliative procedure (symptom relief without curing the disease).

Description of Procedure

Cryosurgery is a major surgical operation, using general anesthesia and requiring a large incision in the abdomen. (Occasionally, these procedures are done with a laparoscope, but usually they are done with open surgery.) The purpose of the cryosurgery is to destroy all present tumors (including a margin of healthy tissue) by freezing them. Cryoprobes are placed directly into the liver and supercooled liquid nitrogen / argon gas flows through the probes to freeze the intended area. This results in cellular crystallization, cell shrinkage and membrane damage. Thawing results in further damage as the area becomes hypotonic and smaller crystals re-crystallize to larger ones. Usually, two freeze-thaw cycles are done in each area because it has been shown to produce a better destruction of cancer cells than a single cycle.

Risks/Side Effects/Complications

Mortality rates for patients undergoing cryosurgery range from 0% to 4% in most published studies. Major complications have been reported in the range of 0-23% of patients. The most common complications are:

• Transient elevation of liver enzymes (short-term increase)
• Coagulopathy (problems with blood clotting)
• Leukocytosis (high white blood cell count)
• Mild fever
• Pleural effusion (fluid around the lungs)
• Hypothermia (cold body temperature)

Other complications include, but are not limited to:

• Bleeding during the procedure / liver surface cracking
• Injury to nearby structures
• Gas embolism (air in a blood vessel)
• Cardiac arrhythmia
• Delayed bleeding
• Thrombocytopenia (reduced platelets in the blood)
• Prolonged prothrombin time (bleeding time)
• Disseminated intravascular coagulation
• Myoglobinuria
• Acute renal failure
• Ascites (fluid in the abdomen)
• Bile leakage
• Infection/abscess
• Liver failure
• Cryoshock syndrome -- thrombocytopenia, disseminated intravascular coagulation, renal failure, hepatic failure, and adult respiratory distress syndrome – potentially fatal multisystem failure

Recovery time and life style changes

Because cryosurgery is done as an open abdominal surgical procedure with general anesthesia, the average hospital stay is five to seven days, if there are no complications. The abdominal incision wound needs to be cleaned three times each day for about the first two weeks following surgery. Patients generally should not drive for at least two weeks after this surgery. In addition, patients are usually advised to limit their physical activity and not to do any heavy lifting for up to three months after surgery. If the cyrosurgery is done laparoscopically, using a scope inserted through a small incision, recovery time and lifestyle changes are decreased.

Effectiveness

With cryosurgery, survival rates for patients with HCC have been reported to be 56 to 60% at one year, 24 to 36% at two years, and 10-23% at three years. For patients with colorectal metastases to the liver, survival rates range from 62-77% at one year and from 50-65% at two years. One study reported only a 5% survival rate at three years. Local recurrence has been reported to be 10% for metastatic patients undergoing cryosurgery.

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