| Chemoembolization
What is Chemoembolization? Back to Top
Chemoembolization is
a way of delivering cancer treatment directly to a tumor. The liver is
the most common part of the body for chemoembolization to be used,
although it can be done in other areas. Under x-ray guidance, a small
catheter is inserted into an artery in the groin. The catheter's tip is
threaded into the artery in the liver that supplies blood flow to the
tumor. Chemotherapy is injected through the catheter into the tumor and
mixed with particles that embolize or block the flow of blood to the
diseased tissue.
Chemoembolization works to attack the cancer in two ways. First, it
delivers a very high concentration of chemotherapy directly into the
tumor, without exposing the entire body to the effects of those drugs.
Second, the procedure cuts off blood supply to the tumor, depriving it
of oxygen and nutrients, and trapping the drugs at the tumor site to
enable them to be more effective.
What are some common uses of the procedure? Back to Top
Chemoembolization
is most beneficial to patients whose disease is limited to the liver,
whether the tumor began in the liver or spread to it (metastasized)
from another organ. Some success has been demonstrated with patients
whose cancer has spread to other areas. Cancers that may be treated by
chemoembolization include:
- Hepatoma (primary liver cancer)
- Metastasis (spread) to the liver from:
- colon cancer
- carcinoid
- islet cell tumors of the pancreas
- ocular melanoma
- sarcomas
- a primary tumor in another part of the body
Depending on the number and type of tumors, chemoembolization may be
used as the sole treatment or may be combined with other treatment
options such as surgery or radiation.
How should I prepare for the procedure? Back to Top
Several
days before the procedure you will have an office consultation with the
physician who will be performing the procedure—an interventional
radiologist. You will have blood drawn at the hospital or at a local
clinic to learn how well your liver and kidneys are functioning and
whether your blood clots normally. Staff also will advise you if there
is to be a change in your medication schedule; be sure the physician is
aware of all the medications you take regularly, particularly those
that affect clotting, such as blood thinners like Coumadin. You will be
admitted to the hospital the day before or the morning of the procedure.
What does the equipment look like? Back to Top
The x-ray
equipment and catheters are the same as those used for catheter
angiography. Several materials can be used to embolize the arteries
feeding the tumor, but the most common are oil and a plastic particle
made from polyvinyl alcohol (PVA).
How does the procedure work? Back to Top
The liver is unique
because it has two blood supplies—an artery (the hepatic artery) and a
large vein (the portal vein). The normal liver receives about 75
percent of its blood supply through the portal vein and only 25 percent
through the hepatic artery. But when a tumor grows in the liver, it
receives almost all of its blood supply from the hepatic artery.
Chemotherapy drugs injected into the hepatic artery reach the tumor
very directly, sparing most of the healthy liver tissue. Then, when the
artery is blocked, the blood is no longer supplied to the tumor, while
the liver continues to be supplied by blood from the portal vein.
Tumors, like all tissues, depend on a steady supply of oxygen and
nutrients carried by the blood. Once the blood supply is cut off by
embolization and the chemotherapy begins its work, the tissue begins to
break down and, in successful cases, the tumor dies. It will appear as
a scar or dead area on subsequent computed tomography (CT) scans or
magnetic resonance imaging (MRI). Over time it may grow smaller.
How is the procedure performed? Back to Top
The first step
is to obtain x-ray pictures showing the arteries to the liver and the
tumor by performing angiography. A sedative will be injected through an
intravenous (IV) line to relax you. The radiologist will numb an area
of the groin with a local anesthetic. A thin catheter is introduced
through a very small incision into the femoral artery, a large groin
vessel, and guided by TV monitoring into the arteries feeding the
liver. Then contrast material is injected and a series of x-rays are
taken allowing even tiny thread-like vessels to be seen. The catheter
is then guided into the branches feeding the tumor and the chemoembolic
material is injected. Repeated x-ray pictures will be taken to confirm
that the tumor has been completely treated.
At the end of the procedure, the interventional radiologist removes
the catheter and pressure will be applied to the groin area for a short
time to prevent bleeding from the site of catheter insertion. You can
expect to stay in bed for six to eight hours afterward.
What will I experience during the procedure? Back to Top
In
some instances, you will be admitted to the hospital on the day before
your procedure, although commonly you will come to the hospital the day
of the procedure. An intravenous (IV) line will be started and you will
receive intravenous fluids. This helps to protect your kidneys during
chemoembolization. In some cases, you may be given a medication called
Allopurinol, which may help protect the kidneys from the chemotherapy
and the products produced by the dying tumor cells. Your nurse will
instruct you in how to use a breathing apparatus called an incentive
spirometer. The purpose of this is to help you inflate your lungs so
that you will not develop pneumonia. Prior to the procedure, you will
be given additional medications to prevent nausea and pain, and
antibiotics to prevent infection.
The sedative will make you feel relaxed and sleepy and you may nod
off for brief periods, but generally will remain awake throughout the
procedure. You may feel slight pressure when the catheter is inserted
but no serious discomfort. Most patients experience some side effects
after chemoembolization. This is called post-embolization syndrome and
consists of pain, nausea, vomiting and fever. Pain is the most common
side effect and occurs because the blood supply to the treated area is
cut off. It can readily be controlled by oral or intravenous
medication. Most patients leave the hospital within 24 to 48 hours of
the procedure, after their pain and nausea have subsided.
You will be sent home with prescriptions for oral antibiotics, pain
medicine and medicine for nausea. Fevers may occur normally for up to a
week after the procedure. Fatigue and loss of appetite are common for
two weeks and may last longer. In general, these are all signs of a
normal recuperation. If your pain suddenly changes in degree or
character, if your fever becomes suddenly higher than it had been or
you notice any other unusual changes, it is important to let your
physician know right away. Most patients can resume their normal
activities within a week.
During the first month following the procedure, it is important to
check in routinely to let the physician know how your recovery is
progressing. You will return for a CT scan or MRI and blood tests to
determine the size of the treated tumor and how well the
chemoembolization worked. If there is tumor on both sides of the liver,
commonly only part of the liver will be treated at first and after one
month, you will return to the hospital for additional
chemoembolization. CT scans are usually done after the completion of
the chemoembolization therapy.
CT scans or MRI will be performed every three months thereafter to
determine how much the tumors ultimately shrink, and to see if and when
any new tumors arise in the liver. The average time before a second
round of chemoembolization is necessary (because of new tumor) is
between 10 and 14 months. Chemoembolization can be repeated many times
over the course of many years, as long as it remains technically
possible and you continue to be healthy enough to tolerate repeat
procedures.
Who interprets the results and how do I get them? Back to Top
The
interventional radiologist can advise you as to whether embolization
was a technical success when the procedure is completed and schedule
your return for additional procedures or for follow-up scans.
What are the benefits vs. risks? Back to Top
Benefits
- 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 in combination with chemoembolization to control
the tumor.
- When cancer is confined to the liver,
most deaths that occur are due to liver failure caused by the growing
tumor, not due to the spread of cancer throughout the body.
Chemoembolization can help prevent this growth of the tumor,
potentially preserving liver function and a relatively normal quality
of life.
Risks
- There is always a chance that embolization material can lodge in the wrong place and deprive normal tissue of its blood supply.
- There is a risk of infection after embolization, even if an antibiotic has been given.
- Because angiography is part of the procedure, there is a risk of an allergic reaction to contrast material.
- Because angiography is part of the
procedure, there is a risk of kidney damage in patients with diabetes
or other pre-existing kidney disease.
- Reactions to chemotherapy may include nausea, hair loss, a decrease in white blood cells, a decrease in platelets and anemia.
- Because chemoembolization traps most of the chemotherapy drugs in the liver, these reactions are usually mild.
- Serious complications from
chemoembolization occur after about one in 20 procedures. Most major
complications involve either infection in the liver or damage to the
liver. Reporting indicates that approximately one in 100 procedures
result in death, usually due to liver failure.
What are the limitations of Chemoembolization? Back to Top
Chemoembolization
is not recommended in cases where severe liver or kidney dysfunction,
abnormal blood clotting or a blockage of the bile ducts exists. In some
cases—despite liver dysfunction—chemoembolization may be done in small
amounts and in several procedures to try and minimize the effect on the
normal liver.
Chemoembolization is a treatment, not a cure. Approximately 70
percent of the patients will see improvement in the liver and,
depending on the type of liver cancer, it may improve survival. Back to Top |
