Radiofrequency Ablation - Lung Tumors

What is Radiofrequency Ablation of Lung Tumors?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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.