Minimally Invasive Tumor Therapy (MITT)

Department of Radiology, Charité – Universitätsmedizin Berlin

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References

  1. http://www.rki.de/Krebs/DE/Content/Publikationen/Krebs_in_Deutschland/kid_2012/kid_2012_c64.pdf?__blob=publicationFile
  2. Best SL, Park SK, Youssef RF, Olweny EO, Tan YK, Trimmer C, Cadeddu JA. Long-term outcomes of renal tumor radio frequency ablation stratified by tumor diameter: size matters. J Urol. 2012 Apr;187(4):1183-9. doi: 10.1016/j.juro.2011.11.096.
  3. Escudier B, Eisen T, Porta C, Patard JJ, Khoo V, Algaba F, Mulders P, Kataja V; ESMO Guidelines Working Group. Renal cell carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2012 Oct;23 Suppl 7:vii65-71.
  4. Campbell SC, Novick AC, Belldegrun A, Blute ML, Chow GK, Derweesh IH, Faraday MM, Kaouk JH, Leveillee RJ, Matin SF, Russo P, Uzzo RG; Practice Guidelines Committee of the American Urological Association. Guideline for management of the clinical T1 renal mass. J Urol. 2009 Oct;182(4):1271-9. doi: 10.1016/j.juro.2009.07.004. Epub 2009 Aug 14.

Radiofrequency Ablation (RFA) for the Treatment of Renal Cell Carcinoma

 

Cancer of the kidney (renal cell carcinoma) accounts for about 1% - 2% of all malignant tumors diagnosed in Germany. Most renal cell carcinomas are discovered by chance when an imaging test of the abdomen (e.g., ultrasound, computed tomography, or magnetic resonance imaging) is done for another reason. The earlier kidney cancer is diagnosed, the better the chance of curing it. Patients in whom kidney cancer is detected because of flank pain or blood in urine often have advanced disease and a poorer chance of being cured.

 

For a long time, surgical removal of the entire kidney (nephrectomy) was the treatment of choice for renal cell carcinoma. While this approach ensures reliable removal of the cancer, it leaves the patient with only one kidney. With refined surgical techniques and new interventional radiology treatments available today, patients with kidney tumors smaller than 4 cm and no apparent metastases elsewhere in the body are candidates for less radical, kidney-sparing surgery (removal of the tumor with only a part of the kidney – so-called partial nephrectomy) or radiofrequency ablation (RFA). RFA is a good choice for patients with high surgical risk or for patients with only one kidney.

 

How Does RFA Work?

 

Radiofrequency ablation (RFA) of a renal cell carcinoma is performed using a thin needle-like electrode (RFA probe). The electrode is passed through a small skin incision into the tumor using ultrasound (US) or computed tomography (CT) guidance (Figure 1). This allows the radiologist to see the electrode inside the patient’s body. Once the electrode has been positioned, an alternating electrical current is passed through the tissue at the electrode tip. This agitates charged particles (ions) and generates frictional heat. The tumor tissue around the electrode tip is heated to a temperature of up to 120°C, which causes the cells to die (a process known as coagulation necrosis). In our department, RFA of kidney cancer is performed with strong intravenous pain medication but without general anesthesia. The whole intervention takes about 90 minutes and requires a hospital stay of about 3 days.

 

Figure 1: Mechanism of radiofrequency ablation (RFA). A thin needle-like electrode (RFA probe) placed within the tumor (red) is used to deliver a high-frequency alternating electrical current (400 - 500 kHz). This radiofrequency energy causes very rapid movement of charged particles (ions) in the tissue around the electrode tip. The resulting frictional heat destroys the tumor cells.

 

What are the Advantages of RFA over other Treatment Options?

 

Long-term survival after RFA treatment of kidney tumors that are smaller than 4 cm is comparable to that of surgical removal. A kidney tumor eliminated by RFA or removed by surgery may return at the site of treatment or elsewhere. Therefore, it is very important to get regular follow-up imaging tests (either CT or MRI) after RFA treatment of the kidney.

 

What are Possible Complications of RFA?

 

RFA is a treatment with very few complications. Some possible complications are related to the insertion and positioning of the RFA electrode. The risk of injury to surrounding organs (e.g., lung or bowel) and of bleeding during this step is lowered by using CT to guide the procedure.

 

Using CT to watch the procedure also helps the radiologist to avoid heat-related complications such as burns of the bowel and other neighboring organs by keeping a large enough distance from these organs during delivery of the radiofrequency energy.

 

After ablation of a very large kidney tumor, the body’s reaction to the decaying tumor may cause fever, chills, and nausea. These side effects develop about 4 – 6 hours after the intervention. In most patients, they can be relieved by medications and will disappear after a couple of hours.

 

Aftercare

 

A patient scheduled for RFA treatment of a renal cell carcinoma will be admitted to our ward for about 3 – 4 days. There are no restrictions on daily activities after the procedure. You should have a follow-up magnetic resonance imaging (MRI) or computed tomography (CT) examination of the kidneys as an outpatient 6 – 8 weeks after treatment and then every 3 months. We prefer MRI for follow-up after RFA of a kidney tumor. If the CT/MRI is done at another site, we kindly ask you to send us a CD with the images for evaluation.

 

For further information on RFA of kidney tumors, please do not hesitate to contact us. We will be happy to answer any questions you may have.

 

  • Contact:

Minimally Invasive Tumor Therapy (MITT)

Charité, Campus Virchow-Klinikum

Department of Radiology

Augustenburger Platz 1

13353 Berlin, Germany

Phone: +49 (0)30/450-557309

Fax: +49 (0)30/450-557947

minimal-invasive-ambulanz@charite.de oder mia@charite.de

 

Case Example

 

 

Figure 2: This case illustrates the use of RFA for the treatment of renal cell carcinoma in the right kidney.

  1. The contrast-enhanced MRI examination performed before treatment shows an enhancing tumor in the kidney (arrow).
  2.  Treatment begins with percutaneous (through the skin) placement of the needle-like electrode (RFA probe) using CT fluoroscopy for guidance. This allows the radiologist to watch the probe while it is advanced into the tumor. Once the probe has been positioned properly, the interventional radiologist starts to apply radiofrequency energy for ablation of the tumor.
  3.  Contrast-enhanced MRI performed 7 years after RFA treatment confirms successful long-term outcome without regrowth of the tumor.