| Radiofrequency Ablation of Lung Tumors
What is Radiofrequency Ablation of Lung Tumors? Back to Top
One
of the most promising alternatives to surgical removal of lung tumors
is eliminating the tumor cells using heat. The technique, called
radiofrequency ablation (RFA), is performed by interventional
radiologists and is much less invasive than open surgery. Guided
primarily by computed tomography (CT) scanning, a small needle
electrode is inserted through the skin and directly into the tumor
tissue. Radiofrequency energy consisting of an alternating electrical
current in the frequency of radio waves is passed through the
electrode. The energy causes the tissues around the needle electrode to
heat up, killing nearby cancer cells. At the same time, heat from
radiofrequency energy closes small blood vessels and lessens the risk
of bleeding. RFA usually causes little discomfort. It is usually done
as an outpatient procedure that does not call for general anesthesia.
What are some common uses of the procedure? Back to Top
Radiofrequency
ablation (RFA) is a useful alternative treatment for patients with
small, early-stage lung cancer who wish to avoid conventional surgery
or are too ill to undergo surgery. The same applies to patients who
have a small number of metastases in their lungs, which are tumors that
have spread from a cancer somewhere else in the body, such as the
kidney, intestine or breast. RFA is not intended to replace surgery,
radiation or chemotherapy in all patients. It may be effective when
used alone or in conjunction with these treatments.
Radiofrequency ablation can be an effective means of relief when a tumor invades the chest wall and causes pain.
Radiofrequency ablation may be used to debulk a lung tumor that is
too large to remove surgically. In this way, the tumor is reduced in
size so that the remaining tumor cells are more easily eliminated by
chemotherapy or radiation therapy. It takes much less time to recover
from RFA than it does from conventional surgery. Chemotherapy usually
can resume after a shorter interval than when more invasive surgery is
performed.
How should I prepare for the procedure? Back to Top
If you
are scheduled for radiofrequency ablation (RFA), you will be asked not
to eat or drink anything starting at midnight the evening before
treatment. If you are taking a blood-thinning drug, your primary care
physician will direct you to stop taking the medication in advance of
RFA. If you use aspirin on a daily basis you should stop doing so two
days before. Patients with a tendency to bleed heavily will require
blood testing to ensure that there will be no excessive bleeding during
the procedure. Unless your physician plans for you to remain in the
hospital overnight, you should come with someone who will drive you
home afterwards.
What does the equipment look like? Back to Top
Radiofrequency
ablation uses needle-like electrodes, an electrical generator producing
alternating electrical current in the range of radio waves, and
grounding pads. Some electrodes are simple straight needles. Others
consist of numerous curved electrodes that are retractable. After the
needle tip is positioned within the tumor, the small electrodes are
made to extend from the tip of the needle, resembling an umbrella. The
generator then is connected to the needle electrode and to the
grounding pads by insulated wires.
How does the procedure work? Back to Top
Radiofrequency
ablation (RFA) works by passing electrical current in the range of
radio waves between a needle electrode positioned in the tumor and
grounding pads placed on the patient's skin. The radiofrequency current
produces a high level of heat within the tumor tissue surrounding the
electrode. Correct settings ensure that the heat will destroy all the
tumor tissue but very little of the surrounding normal lung tissue.
When done properly, RFA can destroy a tumor along with a thin rim of
normal tissue at its edges without affecting most normal lung tissue.
Scar tissue replaces the dead tumor cells and shrinks over time.
How is the procedure performed? Back to Top
The first step
in radiofrequency ablation (RFA) is to precisely locate the tumor with
CT scanning. You will receive sedation through an intravenous (IV) line
placed in an arm vein. The skin is marked at the proper chest wall site
for the procedure and, after cleaning the area with a solution, a local
anesthetic is injected into the skin. A tiny incision measuring about
one-quarter inch is made and the radiofrequency electrode is advanced
into the tumor. The electrode is connected to the electrical generator
and radiofrequency energy is applied for a varying time depending on
the size of the tumor. If a large tumor is present, it may be necessary
to do multiple ablations to be sure that no living tumor tissue is left
behind. After treatment is completed the needle electrode is withdrawn.
A bandage is applied over the skin incision.
What will I experience during the procedure? Back to Top
Most
often, radiofrequency ablation (RFA) is done in a room where CT is
available. You will lie down on a scanning table and receive IV
sedation. You may or may not remain awake depending on how deeply you
are sedated. Injecting local anesthetic before the skin incision
produces a burning feeling that lasts only a few seconds. An RFA
application takes about 10 to 30 minutes. Depending on how many
treatments are needed, the entire procedure will take one to three
hours.
Pain immediately following RFA may readily be controlled by IV or
intramuscular injection of a pain-killer. After RFA, many patients have
mild discomfort that is well controlled by oral pain medications. A few
patients feel nauseous, but this can also be relieved by medication.
You will stay in the recovery room until you are totally awake and
ready to return home. A chest x-ray will be taken to make sure that the
lung has not collapsed from an air pocket created during the procedure.
If a collapse has occurred, it may be necessary to insert a small tube
into the area to remove the air pocket. The tube may need to remain in
place for one to several days. Very few patients still have any degree
of pain a week after RFA.
Who interprets the results and how do I get them? Back to Top
If
you undergo radiofrequency ablation of a lung tumor, you will have
either a CT scan or a magnetic resonance imaging (MRI) exam anywhere
from a few hours to a week afterwards to be certain that all tumor
tissue has been eliminated. A radiologist will interpret the CT scans
and sometimes is able to inform you of the results the same day the
imaging is done. If tumor ablation is confirmed, you may return to your
primary care physician for follow-up care.
What are the benefits vs. risks? Back to Top
Benefits
- Radiofrequency ablation (RFA) is much less invasive than
open surgery when treating primary or metastatic lung tumors. Side
effects and complications are less frequent and less serious when RFA
is carried out.
- Patients who have multiple tumors or
tumors in both lungs usually are not considered to be candidates for
surgery. They may, however, be candidates for RFA.
- Lung
function is better preserved after RFA than after surgical removal of a
tumor. This is especially important for those whose ability to breathe
is impaired, such as current or former cigarette smokers.
- When
part of the tumor persists after RFA, radiation therapy may eliminate
the remaining tumor cells. RFA very effectively destroys the central
part of a tumor—the area that tends not to respond well to
radiotherapy.
- If a tumor recurs in the same region,
it usually can be retreated by RFA. The procedure may be repeated
multiple times if necessary.
- RFA is a relatively
quick procedure that does not require general anesthesia. Recovery is
rapid so that chemotherapy may be resumed almost immediately.
- Even when RFA does not remove all of a tumor, a reduction in the total amount of tumor may extend life for a significant time.
Risks
- It is not uncommon for passage of the radiofrequency
electrode to produce a condition called pneumothorax. This occurs when
a collection of air or gas in the chest cavity collapses part of the
lung. Usually no treatment is needed, but some patients may have a
chest tube placed for up to a few days to drain the air.
- Significant bleeding into the lung is an uncommon complication of radiofrequency ablation (RFA).
- Fluid
may collect in the space between the lung and its covering membrane. If
the patient becomes short of breath, the fluid will have to be removed
using a needle.
- Severe pain after RFA is uncommon, but may last a few days and require a narcotic to provide relief.
- Though
rare, an occasional patient with certain types of underlying lung
disease may become worse after RFA, and in severe cases this may be
fatal.
What are the limitations of Radiofrequency Ablation of Lung Tumors? Back to Top
Radiofrequency
ablation (RFA) may not be practical if the tumor being treated is close
to a critical organ such as the central airways, blood vessels, or
heart. Large lung tumors and those that are difficult to reach may
require repeated RFA treatments. Back to Top |
