Chemoembolization
A technique called transarterial chemoembolization (TACE) is used for some patients with liver cancer or other types of cancer that have spread to the liver. The procedure is a way of delivering cancer treatment directly to a tumor through minimally invasive means.
Although the procedure is not a cure for liver cancer, studies have shown that 70 percent or more of patients experience improvement and, depending on the type of cancer, may live longer. Chemoembolization also may relieve pain and other symptoms, make patients more comfortable, and improve the quality of their lives. Another advantage is that the procedure may be repeated multiple times.
Explaining the Procedure
An angiogram, a real-time X-ray that highlights where blood flows, is performed to help the interventional radiologist see the tumor in the liver without the need for an open incision. The interventional radiologist uses the X-ray images on the TV monitors to insert the catheter (which is like a piece of spaghetti) through a small nick in the skin at the groin and guide it through the artery that feeds the tumor. A combination of chemotherapy drugs and tiny particles, as small as grains of sand, are then injected directly into the tumor.
At the end of the procedure, the catheter is removed and pressure is applied to the entry point to prevent bleeding and a bandage is applied. Patients remain in bed for six to eight hours and leave the hospital within two days.
Chemoembolization can be performed repeatedly on a patient. This procedure can also be used in conjunction with other cancer therapies such as surgery.
Chemoembolization may not be appropriate for patients who have blockages of the veins that supply blood to the liver, cirrhosis of the liver or blockage of the bile ducts.
How Chemoembolization Works
The liver is unique because it has two blood supplies. The portal vein provides 75 percent of the liver’s blood supply and the hepatic artery supplies the remaining 25 percent. Tumors that grow in the liver typically receive their blood supply from the hepatic artery making chemoembolization possible. The drugs can be injected into the artery feeding the tumor while sparing most of the healthy liver tissue that feeds from the portal vein.
The treatment works in three ways to attack the cancer. First, because the chemotherapy is delivered directly to the tumor and doesn't spread throughout the body, stronger doses of cancer-killing drugs can be administered compared to the doses used for standard systemic chemotherapy, which is injected through a vein in the arm. Second, the tiny particles block the artery and decrease the flow of blood to the tumor causing it to shrink. Finally, by blocking the artery, the particles help retain the chemotherapy, keeping it in direct contact with the tumor for a longer period of time – in some cases as long as a month. This technique also may reduce some of the side effects of standard chemotherapy because the drugs are trapped in the liver instead of circulating throughout the body.
What You Can Expect After Treatment
After the procedure, you will receive prescriptions for oral antibiotics, analgesics and anti-nausea medications. Once home, you may experience fevers for up to a week. For the first two weeks, fatigue and loss of appetite are common. These are all signs of a normal recovery. However, if your fever suddenly becomes higher or your pain changes in intensity or character, contact your physician.
Although a majority of patients can resume their normal activities within a week, most are back to their usual state of health in about one month. Throughout this time it's important to let your physician know how your recovery is progressing.
Eventually, you will get a follow-up computed tomography (CT) or magnetic resonance imaging (MRI) scan, as well as blood tests, to determine the size of the treated tumor and how well the chemoembolization worked. CT and MRI scans will continue every three months thereafter to determine how much the tumor has shrunk.
Benefits vs. Risks
Benefits:
- Chemoembolization can stop liver tumors from growing or cause them to shrink in two-thirds of cases treated. This benefit, on average, lasts 10-14 months.
- Chemoembolization can be used in conjunction with other cancer treatments including tumor ablation, radiation and chemotherapy.
- Most patients don't die from the spread of cancer if it is confined to the liver, but rather from liver failure caused by the tumor’s growth. Chemoembolization can help prevent the growth of a tumor, preserving liver function and a relatively normal quality of life.
- Two randomized controlled trials published in 2002 showed improved survival in patients with hepatoma (primary liver cancer) after chemoembolization compared to supportive care alone.
Risks:
- Embolics (tiny particles) can lodge in the wrong place and deprive normal tissue of its blood supply.
- Even if antibiotics are given, there is always a risk of infection after embolization.
- There is a risk of an allergic reaction to the dye used in the angiography X-ray.
- There is a risk of kidney damage in patients with diabetes or other pre-existing kidney disease due to the angiography.
- Nausea, hair loss, decreases in white blood cells and platelets, and anemia may occur due to the chemotherapy drug.
- In roughly one in 20 procedures, serious complications can occur and typically include liver infection or damage to the liver. Liver failure is usually the cause of the 1 percent death rate related to this procedure.
Tumor Ablation
During ablation procedures, interventional radiologists use heat, cold or substances such as alcohol to kill cancer cells by injecting them through catheters directly into the tumor.
One relatively new ablation technique called radiofrequency ablation (RFA) has good results at controlling the spread of cancer in some patients. RFA typically treats cancers than cannot be removed by surgeons because of their size/location or because the patient is not healthy enough to have open surgery. RFA is primarily used to treat cancer in the liver, but it is being studied for use in the kidney, adrenal glands, lung, bone and prostate.
Although RFA is not a cure, there are several benefits of its use:
- Provide a local treatment option when surgery is not possible or too risky
- Shrink larger tumors to a size that makes it possible to remove them surgically or by transplantation
- Relieve pain and other side effects to improve the quality of life for people with cancer
- Treat small tumors in conjunction with surgery of a large mass elsewhere in the liver
Explaining the Procedure
During the technique, an interventional radiologist views the liver tumor through ultrasound or CT. Once located, the doctor makes a small nick in the skin through which a needle is passed. Through the tip of the needle, an electrode is advanced into the tumor. The electrode delivers radiofrequency energy to heat and "burn" the cancerous cells – destroying the tumor. Lasers and microwave energy are other techniques that are being studied to deliver heat to tumors. In a similar technique, called cryoablation, probes are inserted into the tumor to freeze and kill cancer cells.
How Radiofrequency Ablation Works
The radiofrequency energy is sent to the tumor, killing the cancerous cells with little risk to adjacent normal structures. The dead tumor tissue shrinks and slowly forms a scar.
What You Can Expect After Treatment
After the procedure, you will receive medications for pain and possibly nausea. Most RFA procedures can be done as an outpatient or as a brief overnight stay. Once home, you may experience pain for one or two days and there may be a low-grade fever. Most patients experience few significant side effects beyond these, but depending on the size of the tumor treated and its location, some patients may be fatigued or tired. You should be able to resume all normal activities within a day or two, depending on how you are feeling. If any symptoms recur or become worse instead of improving, notify your doctor. Eventually, you will get a follow-up CT or MRI scan, as well as blood tests, to determine the size of the treated tumor and how well the RFA worked. CT and MRI scans will continue every three months thereafter to determine how much the tumor ultimately shrunk. RFA frequently may be repeated to treat all lesions or all parts of a larger tumor. Your doctor will keep you apprised of the need for additional treatment.
New Treatments on the Horizon
Interventional radiology is playing a role in developing new techniques that may improve cancer treatment in the future, including the use of magnetic particles to draw cancer-killing agents into tumors; and the delivery of genetic material, called gene therapy, to fight or prevent cancers. These techniques are still investigational, but they offer new hope in the war against cancer.
Treatments for Cancer Complications
There are also a number of interventional radiology techniques that are used to treat the complications of cancer, including pain, bleeding, obstruction of vital organs, blood clots and infection. Although these treatments do not cure cancer, they can make patients more comfortable, extend life by treating serious complications and improve the quality of life for cancer patients.
Treating Pain
Control of pain is one of the most important aspects of cancer care. Pain not only affects patients’ quality of life and ability to function, it may also lower their tolerance for needed cancer treatments.
In many cancer patients, pain results from the spread of the tumor into surrounding nerves and other tissues. For example, patients with cancer of the pancreas or stomach, sometimes experience pain from the spread of the tumor into a network of nerves and blood vessels in the abdomen called the celiac plexus. To treat the pain, interventional radiologists insert catheters or needles into the affected area and administer alcohol or other agents that destroy the nerves causing the pain.
A particularly painful complication of cancer is when the disease spreads (metastasizes) to bones. In a technique called transcatheter embolization, interventional radiologists inject tiny particles, the size of grains of sand, through a catheter and into the artery that supplies blood to the tumor. The particles cause clotting that decreases the tumor’s blood supply, reducing pain and decreasing the likelihood of bone fracture. Vertebroplasty is a relatively new interventional radiology technique that can relieve the pain of bone fractures that may result from cancers that originate in or spread to the spine. In the technique, a surgical (or medical grade) bone cement is injected under X-ray guidance into a collapsed or weakened vertebra to stabilize the bone, prevent further collapse and relieve pain.
Controlling Bleeding
If a cancer spreads to the blood vessels it may cause hemorrhage or bleeding. An interventional radiology technique called transcatheter embolization can be used to clot the affected blood vessels and stop the bleeding.
Treating Organ Obstruction and Infection
Cancers can obstruct the normal flow of urine or bile, causing these fluids to build up in the body. If left untreated, these conditions are not only painful but may also result in organ failure or infection. Under X-ray guidance, catheters can be inserted to drain the collection of fluids. Often, a small device called a stent is inserted into the organ to bypass the obstruction and allow fluids to drain internally.
Treating Blood Clots
One common side effect of cancer or cancer treatments is the development of blood clots, or emboli, that can be life-threatening if they travel to the brain, lungs or heart. There are two interventional radiology procedures that can reduce the risks posed by blood clots:
- Intra-arterial thrombolysis. In this technique, the interventional radiologist guides a catheter through the blood vessels and to the site of a blood clot. Clot-busting drugs are infused through the catheter to break up the clot.
- Filter placement. This technique is most often used when a blood clot is detected in the blood vessels of the leg (a condition called deep vein thrombosis). The interventional radiologist guides a small filter into the blood vessel that receives blood from the lower body (the vena cava) and carries it to the heart. If the blood clot dislodges from the vein in the leg, the filter will trap it before it can reach the heart or lungs.
Reprinted with permission of the Society of Interventional Radiology © 2004, www.SIRweb.org. All rights reserved.