Ablative Therapies

Cancers can be killed by placing needles into the tumors and killing the surrounding tissue by injecting alcohol, by heating, or by freezing. Needle ablation is most effective with smaller tumors but can be used for cancers up to 5 cm. It is usually reserved for situations where the underlying liver disease makes surgery prohibitively dangerous.

Needle placement is usually directed by CT scan or by ultra-sound. Occasionally needle insertion is done at the time of surgery or laparoscopy, but usually it is performed by the intervention radiologist inserting the needle through the skin. Factors that influence the choice of method include tumor size and the presence of certain adjacent noncancerous structures.

Alcohol injections are suitable for the smaller lesions and usually require multiple injections. Heating, usually called radio-frequency ablation (RFA), requires a specially designed needle system through which electrical current is passed. Freezing, often called cryoablation, also involves a specially designed needle within which the rapid expansion of flowing gas leads to local cooling.

These procedures are generally well tolerated using conscious sedation and narcotics to help with the pain inherent in needle insertion and in heating. Patients are usually able to be treated without hospitalization. Each method has both advantages and limitations which will be reviewed by your physician.

Radiofrequency Ablation (RFA) Therapy

In the U.S., RFA therapy has become the ablation (tissue destruction) therapy of choice among surgeons. The surgeon can perform this procedure laparoscopically (through small holes in the abdomen) or during open exploration of the abdomen. In some instances, the procedure can be done without opening the abdomen by just using ultrasound for visual guidance.

In RFA, heat is generated locally by a high frequency, alternating current that flows from the electrodes. A probe is inserted into the center of the tumor and the non-insulated electrodes, which are shaped like prongs, are projected into the tumor. The local heat that is generated melts the tissue (coagulative necrosis) that is adjacent to the probe. The probe is left in place for about 10 to 15 minutes. The whole procedure is monitored visually by ultrasound scanning. The ideal size of an HCC tumor for RFA is less than 3 cm. Larger tumors may require more than one session. This treatment should be viewed as palliative (providing some relief), not curative.

Percutaneous ethanol (alcohol) injection

In this technique, pure alcohol is injected into the tumor through a very thin needle with the help of ultrasound or CT visual guidance. Alcohol induces tumor destruction by drawing water out of tumor cells (dehydrating them) and thereby altering (denaturing) the structure of cellular proteins. It may take up to five or six sessions of injections to completely destroy the cancer. The ideal patient for alcohol injection has fewer than three HCC tumors, each of which is:

• well defined (distinct margins)
• less than 3cm in diameter
• surrounded by a shell consisting of scar tissue (fibrous encapsulation)
• not near the surface of the liver

Additionally, patients with HCC undergoing alcohol injection should have no signs of chronic liver failure, such as ascites or jaundice. (Patients with liver failure would not be able to tolerate the alcohol injections.)

The most common side effect of alcohol injection is leakage of alcohol onto the surface of the liver and into the abdominal cavity, thereby causing pain and fever. It is important that the location of the tumor relative to the adjacent blood vessels and bile ducts is clearly identified. The reason for needing to locate these structures is to avoid injuring them during the procedure and causing bleeding, bile duct inflammation, or bile leakage.

Cryosurgery

Cryosurgery involves the freezing of the tumor to stop its growth by placing a probe through the skin and into the cancer, guided by imaging such as Computed Tomography (CT), Magnetic Resonance Smaging (MRI), or Ultrasound.

Cryosurgery involves extremely low temperatures which freeze the cancer cells. It is used to treat some kinds of cancer and some precancerous or noncancerous conditions, and is an alternative to surgery for liver cancer that has not spread, or for cancer that has spread to the liver from another site. Cryosurgery may have fewer side effects than other types of treatments, and is less expensive and requires shorter recovery times.