Intra-hepatic Regional and Local Therapy for Hepatobiliary Cancers.

Intra-hepatic Therapy - Chemoembolization

Intra-hepatic or regional therapies deliver therapy via the hepatic artery, which commonly supplies liver tumors, directly into the tumor. Such "liver-directed" therapy may be useful for tumors that are located only in the liver, but cannot be removed by surgery. Some liver tumors (specifically hepatocellular cancer) tend to grow into the portal vein, causing portal vein thrombosis (PVT). Depending on the extent of tumor in the portal vein, liver-directed therapy may not be a safe and effective option. PVT can often be seen on CT or MRI imaging of the liver. Procedures to treat intra-hepatic tumors are performed by specialized doctors called interventional radiologists.

The hepatic artery can be reached via the large common femoral artery in the groin. A thin catheter is then advanced using radiographic guidance through the femoral artery, into the abdominal aorta, through the celiac axis and common hepatic artery and into the proper hepatic artery. Therapy injected into the catheter is delivered directly into the tumor.

Multiple therapies have been delivered in this way. Chemotherapy can be infused in very concentrated doses into the liver tumor. However, when used alone, chemotherapy infused this way is quickly absorbed into the general circulation and can cause the usual side effects associated with chemotherapy. Lipiodol is an oily agent that is preferentially picked up by liver cells and has been used with chemotherapy to keep therapy concentrated in the tumor. Embolization is the placement of small particles into the small vessels that feed the tumor preventing blood flow into the tumor.

Transarterial chemoembolization delivers a mixture of chemotherapy, often with lipiodol followed by particles which block the blood vessels feeding the tumor.Frequent side effects which have occurred with chemoembolization include mild nausea, pain at the tumor site and fever. As with any interventional procedure, there is a small risk of a bleeding, bruising or infection at the injection site in the groin. Less common but more serious side effects include inflammation of the gallbladder (cholecystitis), intestinal and stomach ulcers, and inflammation of the pancreas (pancreatitis). Rarely an infection or abscess may occur at the site in the liver of the killed tumor. Patients with advanced cirrhosis may develop liver failure after this treatment.

Chemoembolization is not a cure for liver cancers. In about two-thirds of cases treated, chemoembolization can stop liver tumors from growing or cause them to shrink. This benefit lasts for an average of 10 to 14 months, depending upon the type of tumor, and usually can be repeated if the cancer starts to grow again. Other types of therapy (tumor ablation, chemotherapy, radiation) may be used incombination with chemoembolization to control the tumor. Tiny polymer spheres embedded with Yttrium90 (radiomicrospheres) provide a different approach that delivers radiation directly into the tumor. Two types of radiomicrospheres are available for infusion into the liver (SirSpheres and Theraspheres). They differ in the size of the particles and the amount of radiation in each particle. All patients considering radiomicrospheres treatment should be thoroughly evaluated by a specialized team, since this treatment can send radiation-loaded particles to the stomach, lungs or other organs. Radiomicrospheres are not a cure for liver cancers. They have been shown to stop liver tumors from growing and in some cases to shrink liver tumors. Depending upon the type of tumor, other types of therapy (tumor ablation, chemotherapy, surgery) may be used in combination with radiomicrospheres to control the tumor.

Radiofrequency ablation (RFA) involves the insertion of a needle/probe through the skin into the liver tumor. This is accomplished under direct CAT scan (CT) or ultrasound (US) guidance. Over the next few minutes, the temperature of the tumor around the probe increases until it reaches lethal levels. The objective is to kill the entire tumor while minimizing any collateral injury to the liver. The procedure is performed under sedation and on an outpatient basis. Occasionally a one night hospital stay may be necessary.

Studies have shown that RFA can be very effective in treating liver tumors, and under certain circumstance be as effective as surgery. This is especially true for smaller lesions (< 3 cm). Additionally RFA can be used to treat lesions in patients who cannot have surgery because of other medical problems or in conjunction with surgery. In all of these cases RFA has been shown to provide a survival benefit and in some cases cure of the targeted cancer.

Radiofrequency ablation for HCC. The probe (red arrows) is seen entering the skin and traversing the liver. The tynes are opened in the shape of an umbrella (circle) where localized heat kills the tumor.

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Intra-hepatic Regional and Local Therapy for Hepatobiliary Cancers.

Intra-hepatic Therapy - Chemoembolization