NEW OPTIONS FOR COMBATING LIVER CANCER

Lawrence Harrison, MD, is careful never to use the term "cure." Or to promise too much to his patients. But he is among a group of pioneering physicians using a relatively new technique called radiofrequency ablation to destroy metastatic and primary liver tumors.

The "radio" in radioablation refers to high frequency electrical energy that is used to create the heat that "cooks" the cancerous tumors. The cells of the tumors – heated to 90 to110 degrees centigrade – are destroyed in about 30 minutes with a minimal effect on normal tissues.

There are three methods for doing this. With percutaneous (through the skin) ablation, which is the most common approach used at UMDNJ-University Hospital, a CT scan guides the physician's hand in directing a needle-thin probe through a small abdominal incision made over the liver. When it reaches its target, wires that deliver heat to the tumor are deployed from its tip. The patient is generally feeling well enough to go home the same day. The probe can also be inserted through a laparoscope or in an open surgical procedure.

"We see many patients at University Hospital with late stage liver disease," comments Harrison, who is also an assistant professor of surgery at UMDNJ-New Jersey Medical School and chief of surgical oncology at the hospital. "The beauty of this procedure is that it can be used when surgery can't be done because the liver function is tenuous, or prior procedures have been unsuccessful and other therapies have failed. And it can be repeated over and over again."

Radioablation is a relatively low risk procedure and well tolerated. To date, 44 patients have undergone roughly 60 ablations at University Hospital. Thirty-one of these patients have had a single ablation, eight have had two ablations and three have had three ablations. The mortality rate is zero, and there have been no major complications, just a few incidences of bruising at the incision site.

The technique does have some serious limitations. According to Harrison, the factors governing its use are the number and size of the tumors and the extent of disease. It is most effective for an isolated liver tumor smaller than five or six centimeters that cannot be removed surgically. "Surgical resection is still the gold standard," he says. If the cancer has spread beyond the liver, it has probably gone too far for ablation to make a difference.

The procedure can be used for multiple liver tumors, ideally no more than three or four. But the University Hospital team has ablated up to eight lesions successfully. The technique can also be used in combination with surgery. For instance, if four tumors can be surgically removed, but one cannot, that one tumor could be "cooked."

Ablation is also used as a bridge to transplant – to hold a tumor in check until an organ is available, Harrison explains. The liver transplant candidate should have a tumor measuring less than five centimeters in size, have poor liver function and have no spread of the cancer to other organs.

Radioablation is sometimes combined with the insertion of a chemotherapy pump to deliver drugs directly to the liver. In that case, a traditional incision is made, the tumor is destroyed and a pump the size of a hockey puck is implanted under the skin. A catheter leading into the pump is filled every two weeks with drugs that go directly into the hepatic artery. Harrison says this is an option when the cancer affects only the liver.

Although the majority of radioablation procedures have been performed to destroy primary liver malignancies, the technique is starting to be used for other cancers, including bone, kidney, breast and prostate. At University Hospital, eight patients have been treated for metastatic colorectal cancer, two for breast cancer and one for a pancreas tumor. According to Harrison, use of the technique for other than liver tumors is still considered experimental.

There is no hard data yet on radioablation in terms of its effect on survival, says the physician, because the procedure is too new. But Harrison is cautiously optimistic and "generally impressed" with what he's seen. "You can achieve a partial if not complete response with very few side effects," he explains. "That's not something you can always achieve with chemotherapy."

Still he cautions patients to remember that this is "one arrow in a quiver." The real key, he says, is a multi-pronged approach. And as technology and drug development advance, the surgical oncologist feels the prognosis for liver cancer patients will move forward as well.