Because RFA and other tumor ablation methods are minimally invasive, they carry a much lower rate of complications than surgical procedures. Complications occur in 1% to 4% of cases.
The most common complications are:
• low-grade fever
• infection at the site of needle electrode insertion
Patients who undergo RFA at the dome or capsule of the liver near the diaphragm tend to experience the most pain.
Some patients may experience post-RFA syndrome, which consists of a low-grade fever and flu-like symptoms. The symptoms of post-RFA syndrome should dissipate within 10 days after the procedure.
Specific Safety Concerns
• Lung collapse
Patients undergoing RFA of the liver or upper kidney face a slight risk of lung collapse when the needle electrode is inserted.
• Tumor lysis-like syndrome
Like other cancer treatments, RFA may cause a buildup of chemicals from dead cells in the bloodstream. If left unchecked, this chemical imbalance can cause heart arrhythmia, kidney failure, or death.
Charring occurs when the heat generated during the procedure rises too quickly. If some areas of the tumor do not reach a high enough temperature, the tissue will remain untreated. Impedance and temperature at the tip of the needle electrode should be monitored constantly to prevent charring.
There are a few options for guarding against charring. First, water- or saline-cooling can regulate the temperature around the needle electrode, preventing any one area from becoming too hot. In addition, some of these needles can distribute fluid throughout the tumor, which helps conduct the heat around the tissue.
Microwave ablation shows promise as a more even heating than RFA and would reduce the risk of charring.
• Heat sink effect
If the tumor is too close to a major blood vessel, the relatively cooler blood can transport the heat caused by the procedure away from the site. Again, this may prevent some tissue from reaching a temperature sufficient to cause cell death.
Some physicians choose to use cryoablation for tumors next to major blood vessels. Microwave ablation may also be less prone to the heat sink effect.
• Thermal stricture
RFA can be risky for tumors located near structures that may suffer from thermal stricture, such as the prostrate or certain areas of the kidney. The first option for dealing with this risk is to use cryoablation rather than heat ablation.
New techniques are emerging to deal with this risk. Some physicians insert small needles near the structure that needs to be protected, then inflate the area between the tumor and delicate structures with air or saline, providing a buffer zone between the heat and the area to be protected.