Microwave ablation is a cancer treatment in which microwave energy is sent through a narrow, microwave antenna that has been placed inside a tumor. The microwave energy creates heat, which destroys the diseased cells and tissue. It is a newer method of treating lung cancer that can target and kill cancerous cells and relieve pain.
How to Prepare for Microwave Ablation
Before treatment with microwave ablation, the patient has a physical examination and medical history, and the physician may order one or more of the following tests:
A common tool for disease screening, blood tests provide information about many substances in the body, such as blood cells, hormones, minerals, and proteins.
Any suspicious mass of tissue or tumor is subject to a biopsy, or removal of cells from the mass. This is the only technique that can confirm the presence of cancer cells. The doctor will use a general or local anesthetic depending on the location of the mass, and then remove a sample of tissue to send to the lab. The sample is sent to a pathologist, a physician who is an expert at identifying diseased cells in tissue samples. Very often, a few stiches are used to help the area heal, and tenderness is felt for a short period of time.
Computed Tomography (CT) Scan
CT scans use x-ray equipment and computer processing to produce 2-dimensional images of the body. The patient lies on a table and passes through a machine that looks like a large, squared-off donut. Doctors order CT scans when they want to see a two-dimensional image of the body to look for tumors and examine lymph nodes and bone abnormalities. If contrast dye is used to improve the computer image, the patient may need to avoid eating or drinking for 4 to 6 hours before the test. Patients should tell their provider before the test if they have any allergies or kidney problems.
Magnetic Resonance Imaging (MRI)
This test uses a magnetic field, radiofrequency pulses, and a computer to produce detailed images of body structures in multiple places. You may be asked to drink a contrast solution for better imaging, and you will most likely lie on a moving table as pictures are taken. MRI is a more detailed tool than x-ray and ultrasound and for certain organs or areas of the body, it provides better images than CT. MRI may not be recommended if you have a pacemaker or other metal implant.
Patients should tell their doctor about any allergies to medication or if they have had problems with anesthesia. The surgeon will give specific instructions about dietary or activity restrictions, and will also instruct whether it is safe take any regular medications prior to the procedure or on the day of the procedure. Patients also may be asked to not eat or drink after midnight on the night before their procedure, and they may wish to ask a friend or family member to drive them to their procedure.
What to Expect During Microwave Ablation
Microwave ablation may be performed on an outpatient basis and may not require general anesthesia—a mild sedative and local anesthetic are often enough. The patient will be positioned on an examining table, and will be connected to machines that monitor heart rate and blood pressure during the procedure. A nurse or technologist will insert an intravenous (IV) line in the patient’s hand or arm to give sedatives and other medications and fluids.
The physician will use a CT scan to precisely locate the tumor. A small incision is made, and an antenna is advanced through the incision to the site of the tumor using CT guidance.
Once the antenna is in place, the energy source will be activated. The heat also helps close small blood vessels and lessens the risk of bleeding. After the abnormal cells are killed, they shrink and turn to scar tissue over time. Each ablation takes between 10 and 30 minutes, and the entire procedure typically takes between one and three hours.
Recovery from Microwave Ablation
Following the ablation procedure, patients are taken to an anesthesia recovery room where their vital signs will be monitored. In addition, they will have a chest x-ray to ensure that their lung has not collapsed from an air pocket created in the space between their lungs and chest wall (called a pneumothorax). If the physician finds a pneumothorax, which is rare, they may have insert a tube to remove the air.
Once stabilized, the patient may be transferred to a hospital room, and may stay overnight. Typically, patients are discharged within 24 to 48 hours after tumor ablation. Recovery is usually quick, and patients are able to resume normal activities within a few days. They may experience discomfort from the ablation needle site, and may experience fatigue, muscle ache, and possibly a low-grade fever (up to 102° F) for several days following the procedure.