What is Radiofrequency Ablation of Kidney Tumors?

Radiofrequency ablation is an image-guided procedure that uses electrical energy and heat in the treatment of cancer. It is a minimally invasive technique in which heat is used to destroy cancer cells. If the size of the tumor is reasonably small, then the entire tumor is destroyed, while in the case of large tumors, the size considerably shrinks.

Kidney cancer is among the 10 most common cancers in both men and women. Men are at a higher risk than women. Renal cell carcinoma (RCC) is the most common type of kidney cancer. Symptoms of kidney cancer include blood in urine (hematuria) back pain, weight loss, fatigue.

Kidney cancer was once detected after patients complained of pain, hematuria and doctors identified a palpable mass, with treatment being radical nephrectomy involving open surgery. Soon there was a detection of kidney tumors through routine ultrasound and other imaging techniques amongst asymptomatic individuals. These tumors were smaller as they were detected early, even before any noticeable symptoms (though some patients can be asymptomatic) and so there was a need to find procedures that were not intrusive and which spared the nephrons from damage. This coincided with a surge in minimally invasive techniques during the mid-1990s, heralding in a change in surgical procedures.

Radiofrequency ablation (RFA) is a technique that was initially used to treat liver cancer but from 1997 the procedure was also used for kidney carcinoma. Currently, RFA is the most commonly used procedure in the treatment of kidney carcinoma. The RFA technique can be used more than once on a patient.

Each Radiofrequency ablation procedure is unique and depends on location, type and size of the tumor, as well as history of chemotherapy or radiation. RFA is used to treat bone, lung, prostate and liver cancers.

Radiofrequency Ablation of Kidney Tumors

Who are the Ideal Candidates for Radiofrequency Ablation?

Ideal candidates for RFA are patients with -

Hereditary renal cell carcinoma
Multiple bilateral renal cell carcinoma in Von Hippel- Lindau
Small RCC with low renal reserve
Poor candidature for open surgery

Who Should Not Opt for RFA?

Patients who should not opt for RFA are those with -

Large tumors ( greater than 4 cms)
Recent acute illness
Tumors in the hilum or the collecting system
Coagulopathy that remains uncorrected
Low life expectancy
Advanced age
Recent cardiac problems

Heart Patients Should not PT for RFA Kidney Tumors

How is Radiofrequency Ablation Carried Out?

The 2 methods of performing an RFA are:

a) Percutaneous

In percutaneous radiofrequency ablation the needle electrodes are inserted through the skin and into the site of the tumor. The heat created by the radio waves destroys the tumor.

b) Laparoscopic

In laparoscopic radiofrequency ablation the needle electrodes are threaded through a small hole in the skin in a procedure known as laparoscopy.

How is Radiofrequency Ablation Performed?

The patient must avoid taking aspirin or blood thinners and fasting from midnight the day before the procedure. When the RFA procedure is performed percutaneously, the patient is administered with local or general anesthesia.

Patients may have to stay overnight for observation after the treatment, though the procedure does not take too long.

How does Radiofrequency Ablation Work?

In radiofrequency ablation, an electrode is placed into the renal tumor using an image guided probe through which high-frequency electric current is transmitted. The probe delivers AC (alternating current) that result in the vibration of ions in the surrounding tissue. These vibrating ions cause frictional heat which causes tissue damage.

The molecular changes in the tumor due to RFA occur in 3 stages

Step 1: The heat generated by friction of ions results in -

Protein denaturation
Cell destruction
Lipid melting
Cellular vaporization

Step 2: Few days later: Tumor destruction occurs due to -

Edema
Coagulation necrosis
Inflammation

Step 3: The necrotic tissue is reabsorbed by the body.

What Does the Success of Radiofrequency Ablation Depend On?

The success of an RFA procedure depends on -

Precise tumor targeting
Distribution of temperature
Temperature of the probe
Generator power

Temperature should be at least above 50^o and latest generators have been found to power at least 100^o. The temperature should not be higher than 105^o as it can cause vaporization and leads to the development of gas.

What are the Imaging Techniques Used?

The imaging techniques that are commonly used are:

Computed Tomography (CT)
Ultrasonography
Fluoroscopic CT
Open interventional CT
Magnetic Resonance Imaging (MRI)

MRI Scan is Used for RFA of Kidney Tumors

Fluoroscopic CT and open interventional CT are techniques that allow real-time monitoring of the ablation procedure.

What is the Post-procedure Care for Radiofrequency Ablation?

The following care and advice should be given to the patient after the procedure:

The patient would have to stay overnight at the hospital
Doing heavy work or carrying heavy objects should be avoided for a few days after the procedure. Though most patients get back to routine within a few days
Driving a car or taking important decisions should not be carried out for 24 hours due to the effects of an esthesia
An oral antibiotic will be provided for a few days after the procedure.

Complications of Radiofrequency Ablation Procedure

The RFA is one of the most tolerated of procedures in cancer treatment. Most patients resume normal activity within a few days after the procedure. Some patients complain of pain and mild fever that may last for a few hours.

However, there are certain risks involved in the procedure and they include:

In percutaneous insertion of the electrode for RFA, patients may complain of pain or paraesthesia at the site of insertion
Perinephric hematoma
Ureteropelvic junction may be obstructed
Damage to ileus or the ureter
Leakage of urine

Leakage of Urine Occurs in RFA Procedure

Benefits of Using Radiofrequency Ablation in Treating Renal Cell Carcinoma

Though there are no long term studies currently available on the use of RFA in treating renal cell carcinoma, initial studies show promising results. The advantages of this procedure are:

It is minimally invasive
It requires short hospital stay
Successful treatments involve reducing tumors to a scar
It has a relatively low complication rate
It can be repeated as required
It is widely available

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