Materials and Methods
We retrospectively evaluated the operative and follow-up data of 30 patients (total 36 tumors)
who underwent RFA and MWA in our clinic between January 2009 and September 2017. All
of the patients who were diagnosed with SRMs by computerized tomography (CT) or
magnetic resonance imaging (MRI) and planned operation with pre-diagnosis of renal tumor.
The reasons for the use of ablation therapy were high surgical and anesthetic risk due to
factors such as the presence of accompanying comorbidities, presence of tumors in the solitary kidney, comorbidities and advanced age and the preference of the patient. Before the
operation, general information about the procedure, possible complications and alternative
treatment methods were explained. Informed consent form of patients was obtained. Ablation
treatment was performed by a single interventional radiologist. As a general approach,
laparoscopic coagulation (L-RFA) was performed on more medial resected tumors, while
ultrasonographic guidance (USG-RFA) or CT guidance (CT-RFA) was applied to posterior or
posterolateral tumors. Biopsy was performed by interventional radiology using a coaxial
system percutaneously before the procedure in biopsied patients. Samples were separated for
pathological examination. Patients who did not undergo biopsy consisted of patients who had
a risk of injury in intraperitoneal organs and seeding due to tumor placement and were
referred to as radiologically typical RCC by an experienced radiologist.
RFA application was performed using RF Ablation Generator with Cool-tip Technology,
Covidien, Massachusetts, USA model RFA generator. In MWA, the Emprint ™ Ablation
Generator with Thermosphere ™ Technology, Covidien, Massachusetts, USA. generator was
used. Sufficient ablation on the tumor tissue was allowed to reach a threshold temperature of
50-60 oC for cell death. The ablation time was a maximum of 12 minutes for a single cycle
and the ablation cycle was repeated when the target temperature remained suboptimal. In the
USG-RFA procedure, the patient was taken to the modified lateral decubitus position adjusted
for localization of the tumor. Sedation was achieved by intravenous 3-5 mg midazolam
hydrochloride and 100-300 μg fentanyl citrate. In addition, local anesthesia with lidocaine
was given to the area where the RFA needle was to be delivered. The RFA needle selected
according to the size of the tumor was placed in the tumor and the tumor was completely
ablated.
L-RFA was performed under general anesthesia for a 2 cm tumor in which only one patient
had a kidney lower pole medially located. The tumor which was radiologically typical RCC could not be reached with a biopsy needle from outside. It was seen that the outer surface of
the tumor was ablated after the procedure.
All patients were checked with dynamic CT or MRI techniques at the 1st, 3rd, 6th, 12th
months and then once a year. Patients who underwent dynamic CT before ablation were
followed up with CT, patients with dynamic MR were followed up with MR. Presence of
contrast-enhanced tumor area and presence of residual tumor at first month control has been
accepted as incomplete ablation. The success rate of tumor ablation is accepted that the
ablation tumor tissue is lost or the tumor size is %50 more regression. Contrast enhancement
in the ablated region during imaging at the 3rd month and later controls in RFA applications
was assessed as disease recurrence. Patients were followed for complications that may occur
during and after the procedure.
Since our study was organized retrospectively, the local ethics committee approval was not
received. The data of our study was evaluated using the function calculations of Microsoft
Excel program. The table was formed with the results obtained.