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RF Ablation

RF Ablation

RF Ablation

Radiofrequency (RF) ablation is a new technique for treating tumors localized to certain organs such as the liver, kidney and, adrenal glands. With this technique relatively small probes are placed into the tumor and RF energy deposited. The RF energy causes the tissue around the tip of the probe to heat up to a high temperature above which cells break apart and die. Since RF kills both tumor and nontumor cells, the goal is to place the probes so that they destroy all of the tumor plus an adequate "rim" of nontumorous tissue around it.

This procedure is usually performed by placing one or more probes through small (less than 1/4 inch) incisions in the skin and using either ultrasound or a CT scanner to guide the tip into the tumor. For those tumors difficult to visualize by either US or CT, this procedure can also be performed in the operating room using a standard and much larger upper abdominal incision.

Tumor Types Treated
Procedure Effectiveness
Risks

Patient Prep

RFA Procedure
The lesion to be treated is first localized by either CT or ultrasound. At times, both CT and ultrasound are used. A corresponding mark is made with a felt tip pen on the skin. The skin over the mark is then cleansed with a cold soap (Betadine) and a large plastic drape placed over it to maintain a sterile field. Xylocaine, a local anesthetic similar to that used by your dentist, is then infiltrated into the skin and soft tissue to numb these areas. There is a burning sensation for a few seconds. One to three tiny incisions, each measuring less than 5mm in length, are then made in the skin. The RF probe, which is similar in size to a biopsy needle, is then advanced into the lesion as guided by ultrasound, CT or both. Once in place the probe is hooked up to an electronic device and RF energy deposited for several minutes, depending upon the size of the lesion being treated. Larger lesions require longer or more treatment sessions. Since it is our goal to destroy both the tumor and a cuff of normal tissue around the tumor, we often treat each lesion more than once. After the treatments are finished the needle is slowly withdrawn. Low power RF energy is also deposited along the needle tract upon withdrawal to minimize bleeding. After the procedure a band-aid will be placed over the small incision(s). For lesions that are difficult to approach through the skin, this procedure can be performed in an open fashion in the operating room. That is, an incision is made in your upper abdomen, similar to that for a liver resection, and then the needle is inserted directly through the liver capsule into the lesion.

Procedure Pain
The deposition of RF energy into the body can be quite painful. Therefore, we offer three options for pain management. The first is using what is called "conscious sedation," whereby medications for pain and sedation are administered intravenously. The second option is "monitored anesthesia care" or MAC, whereby intravenous sedation is administered by an anesthesiologist and/or anesthetist. With MAC the level of anesthesia is generally deeper than it is with conscious sedation. No tube is placed in your windpipe for MAC. The third option is a "general anesthesia," which is also performed by an anesthesiologist and/or anesthetist and which is even a deeper level of sedation. This option also requires placing a tube in your windpipe. For the first 12 hours after the procedure many patients experience only mild pain requiring an occasional Percocet tablet. Some have a bit more pain and require more Percocet for a longer period of time. A few patients have also experienced nausea for which we administer Phenergan either orally or intramuscularly.

After the Procedure
As noted above, there is usually some mild-to-moderate post-procedural pain in the region where the treatment has been performed. This can usually be treated effectively by giving Percocet tablets. Occasionally we administer Phenergan for nausea and vomiting. Many of these side effects are due to the anesthesia rather than the procedure itself. Patients with larger tumors may experience a "post infarction syndrome" which is associated with a very high fever, nausea at times and a generalized lousy feeling or malaise. These symptoms, however, are not associated with infection, are treated with Tylenol orally and usually subside within 12 to 24 hours. Very rarely patients may experience more prolonged pain over a week or more but controlled by Percocet.

We would like you to have a follow-up CT scan one month after the procedure. It will be important to administer intravenous contrast material during that examination. What we find during that scan will determine how often a follow-up CT will be needed thereafter. In some patients, an MRI with intravenous contrast material is an acceptable alternative. Occasionally, a PET scan is performed to help interpret the CT or MRI findings. We would prefer that you have your imaging at St. Mary's primarily because techniques vary widely from institution to institution.

Multiple Procedures
Some lesions, particularly those that are larger, will require more than one treatment session to destroy the entire tumor. In some patients additional lesions will arise at a later date and these will also be retreated. Basically, as long as we can see the lesion with CT or US and are able to navigate the probe into the lesion, we can treat you as many times as necessary

Tumor Types Treated
RF ablation has been primarily used to treat liver tumors, either those that originate in the liver, such as hepatocellular carcinomas, or those that spread to the liver, such as metastatic disease. The technique has also been shown to be effective in treating tumors of the kidneys when surgery is not appropriate. There is also some limited experience in treating tumors in the adrenal gland and the lungs.

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Procedure Effectiveness
Since this is a relatively new procedure most of the long term data is from the treatment of liver tumors.

In patients with tumor isolated to their liver (no tumor in the lungs, lymph nodes, colon, etc.) improvements in survival have been noted. About a third of tumors demonstrate local recurrence although these areas can usually be retreated with RF ablation. Tumors adjacent to a major blood vessel often recur locally since the blood vessel itself draws heat away from the area during the treatment, the so-called "heat sink phenomenon." As a result, the tumor cells next to the blood vessel cannot get hot enough to achieve cellular death.

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Risks
Anytime a needle is placed under the skin there is almost always the risk of bleeding and infection. We will test your blood for a bleeding tendency prior to the procedure. Furthermore, bleeding complications are minimized by "coagulating" the tract with RF energy upon withdrawal of the probe. Furthermore, infectious complications are minimized by administering antibiotics intravenously during the procedure. Other less common complications include diaphragmatic injury which often manifest as right shoulder pain, a skin injury when treating superficial lesions, and a collapsed lung for those lesions that are high under the diaphragm. The latter complication may require placement of a small tube between the lung and chest wall to reinflate the lung. Injury to other structures such as the bowels or blood vessels is unlikely when US or CT are used to guide probe placement. Experience has shown that all of these complications are uncommon, occurring in approximately 5% of patients or less.

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