Microwave Ablation

What is microwave ablation?

Microwave ablation is a minimally invasive procedure used for the treatment of tumors, particularly when classical treatments such as surgery or chemotherapy cannot be performed. Microwave ablation involves guiding a probe to the tumor through a small skin incision. Once the probe is correctly positioned, it generates electromagnetic oscillations that are transferred to the water molecules within the tumor cells. Heat is created through movement and friction of the molecules that “burn” the tumor cells from the inside while sparing the surrounding organ tissue.

When is microwave ablation used?

Microwave ablation is most commonly used for treating thyroid tumors, liver tumors and liver metastases, lung cancer and lung metastases, or kidney cancer. Both primary tumors that have developed within the organ and secondary tumors (metastases) that have spread from a distant organ can be treated using microwave ablation. If surgical treatment is not possible, for instance due to the patient’s poor general condition or because the tumor is located in a difficult or inaccessible area, microwave ablation is a solid alternative.

However, microwave ablation can only be performed on tumors up to 5 centimeters in diameter. 

The cost of treatment is covered by statutory and private health insurance if microwave ablation is medically indicated. Nevertheless, it is always advisable to consult the insurance provider in advance.

How does the procedure work?

Once the indication for microwave ablation has been established by the treating physician, the patient will be admitted to the hospital for a short stay. The actual treatment takes place after taking a medical history, gaining informed patient consent, and performing preliminary examinations.

The procedure starts with the injection of a local anesthetic and administering a sedative. The probe is inserted and advanced into the tumor under continuous image guidance (usually using CT imaging) through a tiny skin incision of just a few millimeters. Once in place, it generates electromagnetic oscillations that cause the molecules to vibrate and rub against each other, particularly water molecules. This results in a temperature increase of up to 100°C. Both the tumor cells and a small area of surrounding healthy tissue, referred to as a safety zone, are burned. This safety zone should be at least half a centimeter wide. The procedure that lasts between 30 to 60 minutes is completely painless due to the local anesthetic. Lastly, the incision site is closed, and the patient remains in the hospital for observation, usually for one or several days. A follow-up examination is scheduled four to six weeks later.

What should be considered before and after microwave ablation?

Patients should refrain from drinking for at least two hours and eating for at least six hours before the treatment. This ensures that the stomach is completely empty during the procedure, reducing the risk of vomiting under anesthesia, which poses a risk of aspiration of stomach contents into the lungs, thereby causing dangerous inflammation or obstruction.

The intake of medications should be discussed beforehand during the consultation. Anticoagulant medication is usually paused to minimize the risk of bleeding.

Moreover, patients should remain in bed for 4-6 hours while the insertion site is compressed with a small sandbag. This prevents further bleeding after the procedure. Physical exertion should be avoided altogether for 24 hours following treatment.

Furthermore, it is very important to contact the treating physician if any symptoms occur in the first few days after microwave ablation that could be related to the procedure.

Advantages and risks of microwave ablation

Microwave ablation is a gentler alternative to surgery. As general anesthesia is not required, all of the risks related to this type of anesthesia are avoided. This makes the procedure safer for patients with severe comorbidities, for example cardiovascular diseases. It is also a suitable alternative for the treatment of otherwise inoperable tumors. The minimally invasive approach allows for the preservation of comparably more healthy surrounding tissue compared to surgery, which is generally associated with a better quality of life.

Nevertheless, microwave ablation also carries some risks. Fever and pain are the most common side effects. The puncture site can bleed or become infected. If the tumor is in the lungs, a complication called pneumothorax may occur. This is when air enters the space between the lung and its membrane, resulting in a collapsed lung. Early detection and treatment requires a short hospital stay.

Which physicians and clinics our specialists in microwave ablation?

While the treatment of cancer is conducted in an interdisciplinary manner, involving specialists from various fields such as medical oncology, surgery, and radiology, microwave ablation is a procedure that is performed by interventional radiologists. As short inpatient monitoring is required after the procedure, it can be carried out either by the radiology department of a hospital or by an affiliated radiology clinic.