Radiofrequency Ablation

//Radiofrequency Ablation

Radiofrequency Ablation is a medical procedure used in cancer treatment to eliminate tumors and metastases. It is also used for arthritis pain, and the pain relief in these cases can last anywhere from 6 months to a year. The percentage of people actually experiencing pain relief is estimated at over 70%. Sometimes, the pain relief lasts for years.

Medical doctors have used the radiofrequency ablation procedure for the past 28 years. Amongst the list of other conditions that it’s been used for are enlarged prostate, heart arrhythmias, and a type of benign bone tumor called osteoid osteoma.

Who Can’t Have RFA Ablation

The only people that should not have radiofrequency ablation are the following:

  • Those who have bleeding disorders
  • Those currently suffering from infections
  • Those who will need deep sedation (for the percutaneous approach)
  • Those whose tumor doesn’t have a normal margin of cells (it’s 100% cancer cells)

How RFA Ablation is Performed

The procedure for ablation therapy is pretty straightforward:

  1. Your body is prepared for an IV line to go into a vein close to the area of the problem.
  2. A type of anesthetic or sedative is administered and the doctor will watch you to make sure the anesthetic is activated in your body.
  3. A 1-2 mm wide 18-gauge to 14-gauge needle (probe) will be inserted into the area of treatment via the aid of x-ray. If the tumor is large, multiple probes will be used. One needle takes care of about 1.6 centimeters of cancerous tissue. However, with advanced technology, this distance can now be extended up to 7 centimeters, which is 2.75 inches. A treatment lasting 30 minutes has very few complications and cells other than the cancer cells don’t die off.The x-ray helps your doctor locate the actual target area to treat it. Once found, an electrode is next inserted into the area so that the stimulation of the cells in the area begins via radio waves. The purpose of this stimulation is to allow the doctor to verify that the placement is exactly correct.Advanced methods of using the technique include slow or pulsed heating, using multiple probes, internal electrode cooling and infusing saline into the area.
  4. Next an RF (radiofrequency) current is dispelled into the area. The stimulation may last anywhere from 30 minutes to 120 minutes. The tissue heats up and then cells susceptible to the heat die. The cells heat up to 50-52 degrees Celsius (122 degrees Fahrenheit to 125.6 degrees Fahrenheit), and after 4 to 6 minutes, the targeted cancer cells die.It is more difficult to use the ablation procedure for a tumor that lies next to arteries or veins larger than 3 mm in diameter. That’s because the transfer of heat could affect the blood vessels negatively. Thus, the doctors may have to clamp off the blood vessels, cause a temporary clot (called an occlusion balloon) in the blood vessels for a few minutes, or create an embolism with chemicals in the blood vessels.After the procedure anywhere from two to six weeks later, new imaging studies such as MRI are taken. They are repeated every 90 days for a little over a year. Doctors want to repeat the ablation if the tumor starts growing. The fear on the part of the doctors is that the new growth will be pretty erratic in its geometry, which would make further treatment quite difficult.

What Type of Precautions Should the Patient Take?

The procedure doesn’t restrict what you eat or drink but it is not a good idea to do any of the following after the ablation therapy:

  • Driving, especially farm equipment
  • Exercising strenuously at the gym or elsewhere

How Effective is Radiofrequency Ablation When Guided By Imagery?

Radiofrequency ablation doesn’t have to be a “blind” procedure. It can be guided by imagery. This isn’t referring to the psychological technique where someone imagines the immune system cells being attacked by one’s own body and the cancer killed. Instead, it means that the doctor has cameras hooked up to the inside of the body so he can see exactly where he is in the tissue, avoid damaging tissues that are healthy, and go right after the cancer cells alone.

The Mayo Clinic has the answer of whether or not radiofrequency ablation is effective when guided by medical imagery systems. The doctors at this prestigious institution just recently published a medical study on the results in July 2017 in the Journal of Vascular Intervention & Radiology. This powerful study tracked 16 patients with prostate cancer who were between the ages of 50 and 86 years old, and had cancer that had metastasized (spread) to other areas of the body.

The doctors found that 27 months after the patients received radiofrequency ablation with the assistance of imagery to “see” what parts of the body were being ablated, 15 of 18 of the tumor metastases were controlled. The tumor recurrence rate only occurred in 16.6% of the tumors. That’s a very low rate, compared to some failed procedures.

In this study, tumors did not recur until 3.5 months later on average so the patients had about 105 days where they were declared tumor free. The local ablation worked. (Local ablation means only the tumor that is in one location is addressed.)

The doctors at Mayo Clinic concluded that the radiofrequency ablation was “feasible and well tolerated and achieved acceptable local tumor control rates” and the method may be useful to patients with prostate cancer who aren’t ready or want to delay androgen-deprivation therapy (ADT).

Freezing Cancer Tumors Works

The type of ablation treatment done at the Mayo Clinic in this study is called Percutaneous Imaging-Guided Cryoablation or PICA. It’s one that closely views tumors as they are being destroying with extreme cold temperatures instead of heat from radio waves. Doctors and patients both like using it because it’s minimally invasive, safe, repeatable, and can be used with other cancer therapies.

When Cryotherapy and Radiofrequency Ablation are used together, according to researchers in France and Italy, PICA has been used in a wide range of patients and tumors with great success.

For example, the following conditions have resulted in reports of curative therapy:

Small primary/secondary lung tumors where RFA ablation is unsuitable (and lung ablation with cryotherapy is used).

In India, doctors reviewed 14 cases where RFA ablation was used for lung metastasis between January 2007 and December 2013. The size of the metastases ranged from 0.5 to 5.0 centimeters. The primary cancer associated with these metastases was liver cancer, colorectal cancer and prostate gland cancer. The average patient age was 50 years old. The medical reports showed complete ablations without local tumor recurrence in 81% of the nodules. The Indian doctors concluded that radiofrequency ablation for lung metastasis can be considered as a relatively safe, effective alternative treatment for lung metastasis.

Bone growths and the relief of pain of bone metastases

Radiofrequency ablation can be performed on both benign bone growths and ones that are cancerous. In bone, the procedure varies a little. The probe is placed in a bone-penetration cannula into the tumor and then activated at 90 degrees Fahrenheit for 4-6 minutes. Success rates for doing the procedure only once are as high as 91-94%. Most reoccurrences can be ablated when the procedure is repeated.

When cancer metastasizes to the bone, the patient suffers from a lot of pain. One study of 43 patients with a bone metastasis that was very painful and resistant to chemotherapy and radiation proved pain relief was possible. The patients had so much pain relief that they used significantly less analgesics to control pain.

Small T1a kidney tumor (where kidney ablation with cryotherapy is used)

These tumors should be ones that occur in the renal cortex. Kidney tumors that are in the interior of the kidney are a potential problem because of the blood vessels that run through this area. The tumors treated should also be less than 3 centimeters in diameter.

RFA ablation therapy may be a great choice of techniques to use for small renal masses, according to the National Institutes of Health and the National Cancer Institute. It’s especially good for patients with a genetic predisposition to have multiple metachronous kidney cancers, such as what happens in von-Hippel Lindau or hereditary papillary renal cancer. So far, results of studies in this area of renal tumors and radiofrequency ablation have shown a 70-90% success rate for the first ablation procedure. When the second procedure is done, the success rates will be higher.

The very best tumor type to respond to RFA is an exophytic tumor of the kidney. This is a tumor that grows outside the surface of the epithelial cells from where it starts. In other words, it’s similar to how a mushroom grows, and how a mushroom can be plucked off the area from where it originates. Complications are rare when ablation is used in the kidneys.

Liver tumors (called liver ablation)

Doctors at Memorial Sloan Kettering Cancer Center in New York reviewed 110 patients that received ablation of colorectal liver metastases between November 2009 and April 2015. Six weeks after the procedure, the margins of the metastases were measured. If the margins had increased in size, this would indicate that the metastases had grown. If the margins had decreased in size, this would indicate that the metastases had shrunk. Ideally, the metastases would be totally gone.

The doctors compared different types of radiofrequency ablation – thermal ablation (ablation with microwave), and ablation of colorectal liver metastases. First of all, you should know that the technique of complete ablation was 93% successful and 97% successful for the microwave version of it. The tumors were completely gone in these cases.

The doctors determined that predictors of success included metastases that had 5 mm margins or less, and perivascular tumors. A perivascular tumor is a rare type of tumor that can occur anywhere in the body. Where this tumor originates from is not known at this time. Most commonly, they are found in the lungs or in the kidneys.

In the study, even the largest tumors (over 10mm) did not metastasize when the RFA ablation was done. They concluded that “Regardless of the thermal ablation modality used, margins greater than 5 mm are critical for local tumor control, with no local tumor progression noted for margins over 10 mm. Unlike RF ablation, the efficiency of microwave ablation was not affected for perivascular tumors.”

If patients have liver cirrhosis along with a liver tumor, they aren’t a candidate for radiofrequency ablation.

Ablation Therapy is Not Available At Every Clinic Yet

Not all doctors will use radiofrequency ablation (local ablation or cryoablation). In one national doctor survey, only 16% of doctors had access to local tumor ablation methods at their place of work. These doctors were primarily ones that were associated with universities.

Yet, not all doctors at universities used ablation therapy because of a lack of radiologists that could assist with and/or perform the procedure, and lack of expertise with the procedure. The doctors that did use ablation therapy used local tumor ablation, percutaneous radiofrequency and cryoablation. We use it here at Williams Cancer Institute because it works well as seen in our hundreds of patient cases. For more information, give us a call.

Sources

Erie, A.J., et al. Retrospective review of percutaneous image-guided ablation of oligometastatic prostate cancer: a single-institution experiment. J Vasc Interv Radiol 2017 Jul; 28(7):987-92. https://www.ncbi.nlm.nih.gov/pubmed/28434661

Cazzato, R.L., et al. Percutaneous image-guided cryoablation: current applications in the oncologic field. Med Oncol 2016 Dec;33(12):140. https://www.ncbi.nlm.nih.gov/pubmed/27837451

Trudeau, V., et al. Local tumour ablation for localized kidney cancer: practice patterns in Canada. Can Urol Assoc J 2015 Nov-Dec;9(11-12):420-3. https://www.ncbi.nlm.nih.gov/pubmed/26788232

Tongdee, T., Tantigate, P. and Tongdee, R. Radiofrequency ablation of lung metastasis not suitable for surgery: experience in Siriraj Hospital. J Med Assoc Thai 2015 Oct; 98(10):1019-27.

Shady, W., etal. Percutaneous microwave versus radiofrequency ablation of colorectal liver metastases: ablation with clear margins (AO) provides the best local tumor control. J Vasc Interv Radiol 2017 Dec 2. https://www.ncbi.nlm.nih.gov/pubmed/29203394

Friedman, M., et al. Radiofrequency ablation of cancer. Cardiovasc Intervent Radiol 2004; 27(5); 427-434. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2408956/
Callstrom MR, Charboneau JW, Goetz MP. Percutaneous CT/US-guided radiofrequency ablation of painful metastases involving bone: a multicenter international study. Radiol Soc North Am Annual Meeting. 2002.

By | 2018-07-24T17:30:21+00:00 June 18th, 2018|Uncategorized|0 Comments

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