Radiofrequency ablation is generally a very safe procedure, but complications can occur. The best way to minimize complications is to have a good grasp of the risks involved with different procedure types and to practice sensible patient care protocols.
Complications range from major — skin burns, infection, or even pneumothorax or intestinal perforation — to minor.
Postablation syndrome is the most common minor complication. Patients may develop a low-grade fever, aches, pain, and other flulike symptoms within a few days of the procedure. The symptoms tend to last no more than five days, according to a study by Dr. Gerald Dodd and colleagues in the July issue of the American Journal of Roentgenology.
The size and placement of the tumor being treated with RFA are the most likely predictors of major complications, according to Dr. Gregory Graves, a thoracic and oncologic surgeon at the Sutter Cancer Center in Sacramento, CA.
"A peripheral lesion can be ablated with excellent local control," Graves said. "You can ablate central lesions, but you need to know where the pulmonary arteries are to avoid puncturing them. The more central the tumor you ablate, the greater the risk of having complications."
In her article in the Clinical Journal of Oncology Nursing, Julia K. Locklin of the National Institutes of Health identifies burns at the site of the grounding pad, bleeding, and electrolyte imbalance as the most likely major complications of RFA. Site-specific major complications include bowel or intestinal perforation, pneumothorax, and intense pain or nerve weakness and paralysis.
Most of these complications can be avoided with proper patient care, according to Locklin. For example, burns can be prevented by placing grounding pads transversely and by monitoring the temperature and appearance of the skin. This is especially important if the lesion being treated is close to the skin.
Graves has seen pneumothorax occur in approximately half of patients he treats for lung tumors using microwave ablation. About half of those experience clinically significant pneumothorax, which requires the insertion of a chest tube. In addition, about 5% of patients experience delayed pneumothoraces — patients have gone home, then up to three weeks later, experienced collapsed lung.
"I think what happens is that the ablated tissue breaks down and becomes more of a liquefied area," Graves said. "If there's a bronchiolus close to it, air can leak out and you can get the lung to fall down. Then you put a chest tube in and reexpand the lung. We treat them conservatively, and essentially all of them get better."
Graves does not minimize the impact of these major complications, but he cautions physicians to take a measured look at the data. Compared with other available treatments for lung lesions, this 25% rate of chest tubes is not that great.
"These are the numbers: About half of patients get a pneumothorax, and about half of those patients have a pneumothorax that is clinically significant requiring a chest tube," Graves said. "I can tell you that every time I do a thorocotomy, the patient winds up with a chest tube."
Pain is the most common patient care issue encountered with most tumor ablation techniques. Again, the site and size of the tumor being treated can influence the amount of pain experienced, and physicians can take steps to minimize pain.
Locklin reports that lesions on the dome or capsule of the liver can result in more pain for the patient, often including pain that radiates to the shoulder. Lesions sited near major nerves can cause more pain.
Peripheral lung lesions can also cause more pain than more central tumors, Graves said. Treating lesions close to the inner chest wall can increase the risk of burns to the parietal pleura.
Graves recommends nonsteroidal anti-inflammatory agents to treat most pain caused by ablation procedures.
New pain relief techniques also show promise. Graves reports that injecting local anesthetic and steroid into the pleura abutting against the ablation site reduced pain and discomfort after the procedure.
Postablation syndrome is also a concern for RFA patients. Dodd's study in the American Journal of Roentgenology found that postablation syndrome is most likely to occur when physicians treat tumors larger than 7.75 cm. Tumors larger than 50 cc in volume and volumes of tissue treated exceeding 150 cc are statistically significant predictors of postablation syndrome.
Treatment of a single encapsulated lesion 3.25 cm or smaller is unlikely to spur postablation syndrome.
Locklin recommends that nurses ensure patients are adequately hydrated after the procedure and that they contact the physician immediately if temperature rises above 100.9°F. The mild flulike symptoms of postablation syndrome should resolve within a week after the procedure.
