Liver Cancer (cont.)

Radioembolization (also known as SIRT, or selective internal radiotherapy) involves attaching a radioactive molecule (called Yttrium) to tiny glass beads. These are then injected directly into the blood vessels feeding the cancers (as in TACE). The radiation particles can then kill tumor cells within a distance of 2.5 mm from them, so that any part of the cancer fed by tiny blood vessels will be exposed to the radiation. It seems to have fewer complications than TACE, although severe liver damage is still possible. The effectiveness is probably comparable to chemoembolization.

Ablation refers to any method that physically destroys a tumor, and is generally only applicable to situations in which there is only one, two, or sometimes three individual cancers in a liver. When there are more than that, it is not possible to reach every one on its own, so a different method such as systemic chemotherapy or TACE must be used.

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. More commonly, the procedure is done without opening the abdomen by just using ultrasound or CT scan for visual guidance.

In RFA, heat is generated locally by high frequency radio waves that are channeled into metal 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 10-15 minutes. The whole procedure is monitored visually by ultrasound scanning. The ideal size of a liver cancer tumor for RFA is less than 5 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, which has been generally replaced by RFA, 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 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.

Source: MedicineNet.com
http://www.medicinenet.com/liver_cancer/article.htm