Key Terms: Lumpectomy, Metastasize, Percutaneous.
Definition
Radiofrequency ablation is a treatment that uses radio waves to create heat and directs the heat though a needle probe at cancer cells to destroy tumors.
Purpose
Radiofrequncy ablation (RFA) is minimally invasive, meaning it involves having to enter the body, but not as severely as major surgery. Because of this and its ability to create heat in a specific location, RFA is a good treatment choice for patients with many types of cancer. RFA also has proven to be an excellent alternative for many patients who have not been able to receive surgery or other cancer therapy, or who have tried other cancer treatments that have failed. For example, some patients cannot have surgery because they have heart or lung conditions that make a long procedure under general anesthesia risky. In other cases, the type, characteristics, or location of the cancer make RFA a better option. The treatment is used not only to help treat cancer, but to ease pain in cancer patients, treat tumors that recur, and to treat some conditions other than cancer.
Liver Tumors
One of the cancers treated most by RFA is cancer of the liver. In many cases, removing the tumor with surgery would not leave enough healthy tissue for the liver to still function. Liver tumors that spread (metastasize) from cancers that started somewhere else in the body also are good candidates for RFA. If a patient has several tumors spread out across the liver, surgeons cannot operate. RFA can eliminate the smaller tumors and a surgeon can follow up by operating on the larger tumor if necessary. In some cases, a previous attempt to treat the tumor, such as with chemotherapy, has failed and RFA is the next option. RFA also might be used to treat a tumor that has recurred.
Lung Tumors
Some patients with lung cancer also are too ill to have conventional surgery or want to avoid the long recovery and possible complications of surgery. RFA once was thought useful only for early, small lung cancers. But research released in 2004 showed that it safely and effectively treated advanced lung cancer as well. The technique also may be used to treat cancer spread to the lung (lung metastases). Physicians also may use RFA to remove most of a tumor that is too large to remove with surgery. The process of making the tumor smaller is called debulking.
Kidney Tumors
Many patients with kidney tumors have surgery, but some patients only have one kidney, making RFA the preferred treatment, since it helps spare the only kidney. As with other organs, RFA is an excellent alternative for patients who have conditions that might prevent them from having surgery or for whom recovery from surgery would be difficult. RFA for kidney (renal) cancer is an excellent choice for patients with more than one tumor, if the tumors are smaller than about 4 to 5 cm.
Bone Cancer and Pain
When cancer spreads to the bones, it can become very painful. Usually, RFA for bone cancer is not used to treat the cancer, but to relieve the pain associated with it. Physicians also may use RFA to relieve pain associated with other cancers by shrinking a tumor that is causing pain, particularly when the tumor has not responded to other treatments or cannot be reached or treated with surgery. This may be referred to as palliation or palliative care.
Other Cancers
Researchers continue to find new uses for RFA to treat a number of cancers. For example, a 2004 report showed that RFA could assist with lumpectomy for breast cancer by giving the patient a cancer-free area around the site where the tumor is removed. RFA also improved cosmetic results. RFA is considered safe, predictable, and cheap when compared to many other treatments.
Precautions
RFA is safe for most patients, and generally can be used in place of surgery for patients who cannot withstand longer surgical procedures, complications, and recovery times. Still, physicians will discuss the benefits and risks of RFA with patients in advance. The procedure usually will require some anesthesia. A medical history and blood tests may rule out some patients or require them to adjust certain medications. Also, some tumors or cancers are not considered treatable with RFA. The number and size of tumors that can be treated in a particular organ may be limited.
Description
Radiofrequency refers to the radio waves, or form of electromagnetic energy, produced by an electrical generator used in the RFA. Electromagnetic energy already is present in the natural environment, as in visible light, microwaves, and radio waves. The energy from radiofrequency is safer than that from x rays because it is absorbed by living tissue as simple heat, which does not change the structure of the cells.
The patient lies on a table in an examination or surgical suite and becomes a sort of electrical circuit through which the radio waves pass. Grounding pads are placed on the patient's back or thighs. Most RFA procedures today are performed by an interventional radiologist. An interventional radiologist is a medical doctor who specializes in performing medical procedures that involved radiology to diagnose and treat disease. The radiologist usually uses ultrasound, but sometimes computed tomography (CT) or magneticresonance imaging (MRI) equipment and video monitors during the procedure to guide the way to the tumor.
Most interventional radiologists guide the small needle or probe that holds the current through the patient's skin and directly into the tumor. This is called the percutaneous method and will make for an easier recovery. Sometimes, a single needle electrode is used; at other times, one straight needle contains many curved needles that retract inside the main probe until its tip is positioned within the tumor. Once the physician has positioned the tumor, the electrodes can open up like an umbrella to deliver heat to a larger area.
The heat can be controlled by the physician. At temperatures above 113 degrees Fahrenheit, RFA "cooks" the tumor. During the procedure, the radiologist is using real-time imaging (ultrasound, CT, or MRI) to locate the cancerous tumor and guide the needle probe. A small needle can accurately heat a precise area. If a tumor is large, the radiologist may have to guide and reposition the probe several times to destroy the entire tumor. After destroying the tumor, the physician also will use the probe to heat and destroy a small margin or rim of healthy tissue around the cancerous tumor. This helps ensure that no single cancerous cell is left behind that can regrow. After the treatment is completed, a small bandage is placed over the probe insertion site. Each RFA treatment takes 15 to 30 minutes, but the entire procedure can take longer, depending on the number of tumors, tumor size, and location. For instance, the interventional radiologist may have to reposition the probe several times for one liver mass, then turn to a second smaller mass, for a total procedure time of 90 minutes. Some procedures can take up to three hours. RFA procedures are performed in hospitals, imaging centers, and physician offices. Most are done on an outpatient basis.
Some pain can be associated with RFA, even with the percutaneous method. Most physicians will insert an intravenous (IV) line in the patient through which they will give anesthesia that makes the patient drowsy, but not completely out. This is often called "conscious sedation." In complex procedures, general anesthesia may be required with an anesthesiologist or nurse anesthetist present and monitoring the patient's vital signs. Sometimes, the physician uses a laparascope to introduce the probe. Although laparoscopy requires a tiny incision, it still is considered surgery. Some surgeons also use RFA on patients as part of general surgery. RFA sometimes is called radiofrequency thermal ablation.
Preparation
Before the RFA procedure, patients may have blood drawn for routine blood tests. The physician, nurse, or scheduler will provide preparation instructions that will include concerns about eating or drinking before the procedure. These instructions will depend on the type of anesthesia planned. Normally, patients will be told not to eat or drink eight hours (or after midnight) before the RFA procedure. Certain medications may need to be changed or stopped before the procedure. For example, blood thinners and aspirin may interfere with the procedure. A patient should reveal all current medications to the interventional radiologist or surgeon and follow preparation instructions.
Questions to Ask Your Doctor
- Why is radiofrequency ablation the best alternative for my cancer?
- What are the risks involved in the treatment?
- How many of these procedures have you performed?
Aftercare
The treatment team will move the patient to a recovery room following the procedure to allow anesthesia to wear off and to receive pain medication as needed. Some patients also have nausea and will receive medications and instructions for nausea and pain care before leaving the facility. Patients will have to remain in bed for the first few hours following the procedure, but seldom have to stay overnight from RFA. However, those having the procedure through surgery will require some hospital stay.
Once they return home, patients will be instructed to drink plenty of fluid and to take a prescription narcotic such as Percocet for the first day or two if pain continues. The physician likely will instruct patients not to drive a car or make important decisions for 24 hours after the procedure because of anesthesia effects. Excessive physical activity also is discouraged. However, most patients can resume normal diet, physical activity, and sexual activity within a few days of RFA.
Risks
The risks associated with radiofrequency ablation are relatively minor compared to those associated with many other cancer treatments, particularly surgery. However, no procedure is risk-free. Although rare, there is a risk of serious injury if the needle makes a hole (perforates) a nearby organ. If this happens, the patient may require surgery to repair the injury. There also is a minor risk of infection at the site where the probe is inserted. Patients may experience bruising or bleeding. Another possible complication from RFA to the lungs is air or gas in the chest cavity (pneumothorax), which may require a chest tube for a few days to drain the air. Finally, RFA is a complicated procedure and should be performed only by a physician trained specifically to do the procedure. Most interventional radiologists have extensive experience in these and similar procedures, but patients can check with accrediting societies, local medical societies and their primary care physicians and ask questions of the physician who will perform the procedure.
Normal Results
Results vary, depending on the location, type, and size of tumor. Normally, scar tissue replaces the tumor cells destroyed by RFA and shrinks over a period of time. Patients should have no pain from the procedure after a few days.
Abnormal Results
If pain continues for more than a few days, the patient should contact the physician. Some patients also develop flu-like symptoms and fever following RFA that can last for a few weeks. Bleeding after RFA has been reported. If it continues and is severe, the patient may have to return for an additional RFA procedure or surgery to control the bleeding. Sometimes, cancer recurs following RFA because tumors are so tiny they cannot be seen. Some patients will need another RFA procedure in the future.
Resources
Periodicals
"Breast Cancer Study Examines New Radiofrequency Ablation Assisted Lumpectomy." Medical Devices & Surgical Technology Week (Dec. 12, 2004):34.
"CIGNA HealthCare Will Cover Radiofrequency Ablation Liver Treatment." Drug Week (Oct. 15, 2004):403.
Livraghi, Tito, et al. "Treatment of Focal Liver Tumors With Percutaneous Radiofrequency Ablation: Complications Encountered in a Multicenter Study." Drug Week (Feb. 2003):441–451.
"Lung Cancer Survival Statistics Reported in Trial Using Radiofrequency Ablation." Cancer Weekly (Dec. 28, 2004):151.
Patti, Jay W., Ziv Neeman, and Bradford J. Wood. "Radiofrequency Ablation for Cancer-associated Pain." The Journal of Pain (Dec. 2002):471–473.
"Radiofrequency Ablation Safe and Feasible for Eradicating Lung Tumors." Clinical Oncology Week (Aug. 23, 2004):49.
Organizations
Society of Interventional Radiology. 10201 Lee Highway, Suite 500, Fairfax, VA 22030. 703-691-1805. http://www.sirweb.org.
Other
ARRS: Radiofrequency Ablation Effective in Treating Advanced Lung Cancer. Web site news release. Doctor's Guide Publishing Ltd. American Roentgen Ray Society, 2003. http://www.docguide.com/news.
Percutaneous Radiofrequency Ablation. Web page. National Institutes of Health, Warren Grant Magnuson Clinical Center, 2001. http://www.nih.gov.
Radiofrequency Ablation of Liver Tumors. Web page. Radiological Society of North America, 2005. http://www.radiologyinfo.org/content/interventional/rf_ablation.htm.
Radiofrequency Ablation of Lung Tumors. Web page. Radiological Society of North America, 2005. http://www.radiologyinfo.org/content/interventional/rfalung.htm.
Treatments. Web page. Society of Interventional Radiology, 2003. http://www.sirweb.org/patPub/cancerTreatments.html.
—Teresa G. Odle
