What is Radiofrequency Ablation

Radiofrequency ablation (RFA) is a medical procedure in which part of the electrical

conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat
generated from medium frequency alternating current (in the range of 350–500 kHz).

 RFA is generally conducted in the outpatient setting, using either local anesthetics or conscious

sedation anesthesia.

Two important advantages of RF current (over previously used low frequency AC or pulses of DC)
are that it does not directly stimulate nerves or heart muscle and therefore can often be used without
the need for general anesthetic, and that it is very specific for treating the desired tissue without
significant collateral damage.

Documented benefits have led to RFA becoming widely used during the last 15 years.[2][3] RFA
procedures are performed under image guidance (such as X-ray screening, CT scan or ultrasound)
by an interventional pain specialist (such as an anesthesiologist), interventional
radiologist, otolaryngologists, a gastrointestinal or surgical endoscopist, or a cardiac
electrophysiologist, a subspecialty of cardiologists.

In radiofrequency ablation, imaging techniques such as ultrasound, computed tomography (CT) or

magnetic resonance imaging (MRI) are used to help guide a needle electrode into a cancerous
tumor. High-frequency electrical currents are then passed through the electrode, creating heat that
destroys the abnormal cells.
top of page

What are some common uses of the procedure?

Radiofrequency ablation is used to treat many types of liver cancer. The two most common
types are:

 hepatocellular carcinoma, which is a primary liver cancer (meaning it begins in the liver).
 colon cancer that metastasizes or spreads from the colon to the liver.

In general, radiofrequency ablation is most effective treating tumors that are less than one and
a half inches in diameter. It may be used in addition to chemotherapy or radiation therapy or as
an alternative to surgical treatment.

Radiofrequency ablation is a viable and effective treatment option if you:

 are not a good candidate for surgery because your tumor is difficult to reach.
  have other medical conditions that make surgery especially risky.
 would not have enough liver tissue left for the organ to function adequately following
the surgical removal of a tumor.
 have liver tumors that have not responded to chemotherapy or that have recurred after
being removed surgically.
 you have several small liver tumors that are too spread out to be removed surgically.

top of page

How should I prepare?

You should report to your doctor all medications that you are taking, including herbal
supplements, and if you have any allergies, especially to local anesthetic medications, general
anesthesia or to contrast materials containing iodine (sometimes referred to as "dye" or "x-ray
dye"). Your physician may advise you to stop taking aspirin, nonsteroidal anti-inflammatory
drugs (NSAIDs) or blood thinners for a specified period of time before your procedure.

Prior to your procedure, your blood may be tested to determine how well your kidneys are
functioning and whether your blood clots normally.

Women should always inform their physician and x-ray technologist if there is any possibility
that they are pregnant. Many imaging tests are not performed during pregnancy so as not to
expose the fetus to radiation. If an x-ray is necessary, precautions will be taken to minimize
radiation exposure to the baby. See the  Safety page  for more information about pregnancy and x-
rays.

You will likely be instructed not to eat or drink anything after midnight before your procedure.
Your doctor will tell you which medications you may take in the morning.

You should plan to have a relative or friend drive you home after your procedure.

You may be asked to wear a gown during the procedure.

top of page

What does the equipment look like?

The equipment used in this procedure depends on the type of imaging used—magnetic
resonance (MR), computed tomography(CT), or ultrasound. Other equipment such as needle
electrodes, an electrical generator and grounding pads may also be used.

Radiofrequency equipment
There are two types of needle electrodes: simple straight needles and a straight, hollow needle
that contains several retractable electrodes that extend when needed.
The radiofrequency generator produces electrical currents in the range of radiofrequency
waves. It is connected by insulated wires to the needle electrodes and to grounding pads that
are placed on the patient's back or thigh.

Computed Tomography (CT)

The CT scanner is typically a large, box-like machine with a hole, or short tunnel, in the center.
You will lie on a narrow examination table that slides into and out of this tunnel. Rotating
around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a
ring, called a gantry. The computer workstation that processes the imaging information is
located in a separate control room, where the technologist operates the scanner and monitors
your examination in direct visual contact and usually with the ability to hear and talk to you
with the use of a speaker and microphone.

Ultrasound equipment
Ultrasound scanners consist of a console containing a computer and electronics, a video display
screen and a transducer that is used to do the scanning. The transducer is a small hand-held
device that resembles a microphone, attached to the scanner by a cord. Some exams may use
different transducers (with different capabilities) during a single exam. The transducer sends
out inaudible, high—frequency sound waves into the body and then listens for the returning
echoes from the tissues in the body. The principles are similar to sonar used by boats and
submarines.

The ultrasound image is immediately visible on a video display screen that looks like a
computer or television monitor. The image is created based on the amplitude (loudness),
frequency (pitch) and time it takes for the ultrasound signal to return from the area within the
patient that is being examined to the transducer (the device used to examine the patient), as
well as the type of body structure and composition of body tissue through which the sound
travels. A small amount of gel is put on the skin to allow the sound waves to best travel from
the transducer to the examined area within the body and then back again.

Magnetic Resonance Imaging

The traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You
will lie on a moveable examination table that slides into the center of the magnet.

Some MRI units, called short-bore systems, are designed so that the magnet does not
completely surround you. Some newer MRI machines have a larger diameter bore which can be
more comfortable for larger size patients or patients with claustrophobia. Other MRI machines
are open on the sides (open MRI). Open units are especially helpful for examining larger
patients or those with claustrophobia. Newer open MRI units provide very high quality images
for many types of exams; however, older open MRI units may not provide this same image
quality. Certain types of exams cannot be performed using open MRI. For more information,
consult your radiologist.
The computer workstation that processes the imaging information is located in a separate
room from the scanner.

Other equipment that may be used during the procedure includes an intravenous line (IV),
ultrasound machine and devices that monitor your heart beat and blood pressure.
top of page

How does the procedure work?

Radiofrequency ablation works by passing electrical currents in the range of radiofrequency
waves between the needle electrode and the grounding pads placed on the patient's skin.
These currents create heat around the electrode, which when directed into the tumor, heats
and destroys the cancer cells. At the same time, heat from radiofrequency energy closes small
blood vessels and lessens the risk of bleeding. The dead tumor cells are gradually replaced by
scar tissue that shrinks over time.

Ultrasound, computed tomography or magnetic resonance imaging may be used to help the
physician guide the needle electrode into the tumor.
top of page

How is the procedure performed?

Image-guided, minimally invasive procedures such as radiofrequency ablation are most often
performed by a specially trainedinterventional radiologist in an interventional radiology suite or
occasionally in the operating room.

Radiofrequency ablation is often done on an outpatient basis.

You will be positioned on the examining table.

You may be connected to monitors that track your heart rate, blood pressure and pulse during
the procedure.

A nurse or technologist will insert an intravenous (IV) line into a vein in your hand or arm so
that sedation medication can be given intravenously.

The area where the electrodes are to be inserted will be sterilized and covered with a surgical
drape.

Your physician will numb the area with a local anesthetic if the procedure is to be done while
you are awake. If general anesthesia is used, you will have a breathing tube placed through
your mouth and into your trachea after you are asleep. The breathing tube will be connected to
a breathing machine while you are asleep.

A very small nick may be made in your skin to make it easier to pass the RFA electrode into your
liver.
Radiofrequency ablation is performed using one of three methods:

 Surgically.
 Percutaneous, in which needle electrodes are inserted through the skin and into the site
of the tumor.
 Laparoscopic, in which needle electrodes within a thin, plastic tube is threaded through
a small hole in the skin in a procedure called a laparoscopy.

Using imaging-guidance, your physician will insert the needle electrode through the skin and
advance it to the site of the tumor.

Once the needle electrode is in place, radiofrequency energy is applied. For a large tumor, it
may be necessary to do multiple ablations by repositioning the needle electrode into different
parts of the tumor to ensure no tumor tissue is left behind.

At the end of the procedure, the needle electrode will be removed and pressure will be applied
to stop any bleeding and the opening in the skin is covered with a dressing. No sutures are
needed.

Your intravenous line will be removed.

Each radiofrequency ablation takes about 10 to 30 minutes, with additional time required if
multiple ablations are performed. The entire procedure is usually completed within one to
three hours.
top of page

What will I experience during and after the procedure?

Devices to monitor your heart rate and blood pressure will be attached to your body.

You will feel a slight pin prick when the needle is inserted into your vein for the intravenous line
(IV) and when the local anesthetic is injected. The arteries have no sensation. Most of the
sensation is at the skin incision site which is numbed using local anesthetic.

If the case is done with sedation, the intravenous (IV) sedative will make you feel relaxed and
sleepy. You may or may not remain awake, depending on how deeply you are sedated.

If you are put under general anesthesia, your throat may be sore after you wake up. This is
caused by the breathing tube that was placed in your throat while you were asleep.

Pain immediately following radiofrequency ablation can be controlled by pain medication given
through your IV or by injection. Afterward any mild discomfort you experience can be
controlled by oral pain medications. Patients may feel nauseous, but this can also be relieved
by medication.

You will remain in the recovery room until you are completely awake and ready to return home.
You should be able to resume your usual activities within a few days.

Only about ten percent of patients will still have pain a week following radiofrequency ablation.
top of page

What are the benefits vs. risks?

Benefits

 Radiofrequency ablation can be an effective treatment for primary liver cancer and for
cancers that have spread to the liver in select patients whose liver tumors are
unsuitable for surgical resection.
 In most studies, more than half of the liver tumors treated by radiofrequency ablation
have not recurred. The success rate for completely eliminating small liver tumors is
greater than 85 percent.
 Treatment-related serious complications are infrequent and discomfort is minimal.
 Radiofrequency ablation may be used repeatedly to treat recurrent liver tumors.
 The percutaneous method of radiofrequency ablation, in which electrodes are inserted
through the skin, is minimally invasive, produces few complications, and does not
require hospital admission.
 RFA is a relatively quick procedure and recovery is rapid so that chemotherapy may be
resumed almost immediately in patients who need it.
 Radiofrequency ablation is less expensive than other treatment options.
 No surgical incision is needed—only a small nick in the skin that does not have to be
stitched closed.

Risks

 Any procedure where the skin is penetrated carries a risk of infection. The chance of
infection requiring antibiotic treatment appears to be less than one in 1,000.
 Depending on the site of treatment, radiofrequency ablation may cause brief or, rarely,
long-lasting shoulder pain; inflammation of the gallbladder that subsides after a few
weeks; damage to the bile ducts resulting in biliary obstruction; or thermal damage to
the bowel.
 Roughly one in four patients may develop a "post-ablation syndrome" with flu-like
symptoms that appear three to five days after the procedure and usually last about five
days. An occasional patient may remain ill for two to three weeks.Acetaminophen or
ibuprofen taken by mouth is commonly used to control fever and other symptoms.
 Some cases of bleeding have been reported but it usually stops on its own. If bleeding is
severe, an additional procedure or surgery may be needed to control it.
 Organs and tissues near the liver, such as the gallbladder, bile ducts, diaphragm and
bowel loops, are at risk of being injured. Although this occurs only 3 to 5 percent of the
 time, it may require surgical correction. The risk of this complication is related to the
location of the liver tumor that is treated.
 Less than one percent of patients may develop a localized infection (abscess) at the site
of the tumor ablation three to four weeks after the treatment. A liver abscess will
require tube drainage and antibiotics to cure. Patients who have had a surgical
procedure in which the liver bile duct has been connected to a loop of bowel are at
much greater risk of developing a liver abscess after ablation.
 Women should always inform their physician or x-ray technologist if there is any
possibility that they are pregnant. See theSafety page  for more information about
pregnancy and x-rays.
 This procedure may involve exposure to x-rays. However, radiation risk is not a major
concern when compared to the benefits of the procedure. See the  Safety page  for more
information about radiation dose from interventional procedures.
 Severe pain after RFA is uncommon, but may last a few days and require a narcotic to
provide relief.

top of page

What are the limitations of Radiofrequency Ablation of Liver

Tumors?
There is a limit to the volume of tumor tissue that can be eliminated by radiofrequency
ablation. This is due to limitations with current equipment. Hopefully technical advances will
permit larger tumors to be treated in the future. Radiofrequency ablation also cannot destroy
microscopic-sized tumors and cannot prevent cancer from growing back.