Radio-frequency ablation (RFA)
RFA is a frequently used and scientifically widely researched minimally invasive therapy for the local treatment of primary (intrinsic to the liver) and secondary (metastatic) liver tumours.
In recent years, numerous studies have scientifically concerned the safety and efficiency of this technique, which means that RFA is now regarded as the treatment of choice for inoperable liver tumours.
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How does RFA work?
RFA’s mechanism of effectiveness uses the fact that cells can be destroyed with heat (heat coagulation). To do this, an approximately 3 mm-thick needle electrode is inserted into the tumour. The doctor monitors this procedure either on the ultrasound device’s monitor, a CT scan or an MRI scan (Figure 1).
Normally, a single RFA treatment is sufficient for small liver tumours. If the development of new liver tumours is picked up at later follow-up, RFA can be repeated at any time.
Several international studies have shown that local tumour control rates can be achieved with RFA that are comparable with those of surgical resection.
For which patients do we recommend RFA?
RFA represents a treatment option for patients who are unsuitable for surgery – e.g. due to previous abdominal surgery. However this option is restricted to tumours
- that are no larger than 4 – 5 cm in size (larger tumours are not treated with RFA at our facility, since in these cases other minimally invasive methods have been found to more suitable, such as high-dose brachytherapy).
- that are not located close to heat-sensitive organs such as the large central bile ducts or loops of bowel.
- with a normal blood supply.
(Too great a blood supply to the tumour or surrounding major blood vessels can cause heat to be transported. In these circumstances, the temperature is then no longer high enough to destroy the tumour cells).
How is RFA carried out?
Beforehand
A precise determination of the indication and careful preparation are needed for RFA.
In preparation for the procedure, we evaluate the case history and any diagnostic results already available, such as CT images, MRI scans and, if available, PET-CT scans (positron emission computed tomography). To this end, we request that a detailed medical history is provided, with a list of the treatments already applied, an indication of the progression of the disease, and the most up-to-date diagnostic images available.
Based on the documents supplied, we can check whether the most important requirements for RFA are fulfilled. If this is the case, the patient will be invited for a further consultation and work-up at our outpatient clinic for minimally invasive tumour therapy. You can arrange an appointment for this by calling +49 (0)30 / 450 557 309.
During
Patients remain on our unit for around three to four days for the treatment.
The procedure is generally very well tolerated under local anaesthetic and a strong pain killer so that in most cases a general anaesthetic is not needed.
The needle electrode is positioned through the skin (percutaneously) into the tumour. The activated needle electrode causes the tissue in the tumour area to heat up to around 100°C. The tumour cells die (coagulation necrosis) and are removed (ablation). The procedure takes around 15 to 30 minutes. The needle electrode is then removed from the body and the incision canal is sealed.
After
There are no restrictions to normal everyday activities following the procedure. After six to eight weeks and then every three months, we recommend an outpatient MRI scan of the liver – ideally with liver cell-specific contrast medium in order to check the success of the ablation and to rule out any new liver tumours.
The patient can have this MRI scan done as an outpatient at our facility or elsewhere. If the MRI scan is carried out elsewhere, we would be grateful if the image data could be sent to us via CD-ROM for quality assessment.
What complications should patients be aware of?
Thanks to the image-guided introduction of the RFA probe into the tumour without any large skin incisions, the RFA procedure is tolerated very well and has few complications.
Complications can potentially arise at the skin opening through which the RFA probe is positioned. Injuries to surrounding organs or bleeding can generally be avoided by carrying out the procedure under CT guidance.
Other, very rare complications include thermal damage to surrounding organs such as the skin, kidney, bowel, stomach or lungs.
Case example
Figure 2: The example shows RFA being carried out to treat a small liver cell carcinoma in a patient with marked liver cirrhosis.
1. The contrast-enhanced CT scan carried out before the treatment shows a bright tumour focus (arrow) below the liver capsule (sub-capsular).
2. During the procedure, the RFA probe is advanced under CT fluoroscopy guidance into the tumour. Once the probe is correctly positioned, the tumour is ablated.
3. The CT with contrast medium carried out after the RFA shows successful ablation of the tumour (arrow), which now no longer takes up any contrast medium and which appears darker than before the treatment.
Bibliography
- S3-Leitlinie Hepatozellulläres Karzinom. www.leitlinienprogramm-onkologie.de/fileadmin/user_upload/Downloads/Leitlinien/HCC/S3-HCC-OL-Langversion-V1.0.pdf [external PDF, 2,8 MB]
- Forner A, Llovet JM, Bruix J. Hepatocellular carcinoma. Lancet. 2012;379(9822):1245-55
- Gervais DA, Goldberg SN, Brown DB, Soulen MC, Millward SF, Rajan DK. Society of Interventional Radiology position statement on percutaneous radiofrequency ablation for the treatment of liver tumors. J Vasc Interv Radiol. 2009;20(1):3-8
- Goldberg SN, Charboneau JW, Dodd GD, 3rd, Dupuy DE, Gervais DA, Gillams AR, et al. Image-guided tumor ablation: proposal for standardization of terms and reporting criteria. Radiology. 2003;228(2):335-45
- Goldberg SN, Grassi CJ, Cardella JF, Charboneau JW, Dodd GD, 3rd, Dupuy DE, et al. Image-guided tumor ablation: standardization of terminology and reporting criteria. J Vasc Interv Radiol. 2009;20(7 Suppl):S377-90