Cancer can be treated either systemically by administering anti-cancer agents or locally at the site of the tumor. Systemic treatments, such as chemotherapy, are very effective against cancers. However, local treatments may be more effective and cause fewer overall side effects. Local treatments include surgery and radiation, along with minimally invasive procedures such as embolization and thermal ablation. Recent advancements have increased the effectiveness of thermal ablation, and it is becoming more common in the treatment of certain cancer tumors.
In thermal ablation, extreme heat or cold is applied at the site of the tumor to kill off the cancerous cells. Different options include radiofrequency ablation (RFA), cryoablation, microwave therapy, laser ablation, and high-intensity focused ultrasound. Currently, RFA and cryoablation are the two most commonly used thermal ablative therapies in the US.
In thermal ablation, an interventional radiologist makes a small nick in the skin above the tumor site, then guides a probe through the skin into the liver, lung, or kidney. Using imaging guidance such as ultrasound, CT, or MRI, the interventional radiologist is able to place the probe directly adjacent to the tumor. In RFA, the probe heats the tumor and kills the cancerous cells without damaging the rest of the organ. Cryoablation is performed in a similar way to RFA, except that extreme cold, rather than heat, is used to freeze and kill off the cancerous cells.
Frequently Asked Questions
Thermal ablation is most appropriate when the tumor is confined to the organ (such as the kidney, lung, or liver) and surgery is not an option. Patients may be contraindicated for surgery, have recurrent tumors, or may have failed conventional therapies. Thermal ablation may also be performed prior to surgery to decrease the overall number of tumors in the organ or to shrink a tumor to increase the chances that surgery will effectively treat the cancer.
In RFA, the patient is made into an electrical circuit by placing grounding pads on the thighs that are connected to the probe inserted into the tumor. The energy at the exposed tip causes ionic agitation and frictional heat, which cooks the tumor and leads to cell death and coagulation necrosis, if hot enough (above 50 degrees C). The tumor cells are gradually replaced by fibrosis and scar tissue. Over the coming months, the treated tissue shrinks in volume.
In cryoablation, a coolant, such as liquid nitrogen, is circulated through the probe, and the cells are destroyed through a cycle of freezing and thawing. Most tumors die at –40º C, and repeated sessions may improve results.
Serious complications are rare, and any pain can usually be effectively managed with medications. Patient’s usually return home the same day or may spend one night in the hospital for observation.
Thermal ablation provides safe and effective local treatment of some cancers, with some results similar to those seen with surgical resection. Every case is different, so a consultation with an interventional radiologist is required for each case. Thermal ablation could also impact palliative treatments for incurable disease by providing pain relief.
Percutaneous, minimally invasive, local treatment is an attractive tool for the cancer patient, especially for tumors in the liver, kidney, and lung. Local treatment preserves the healthy organ tissue, has potentially fewer systemic complications and side effects than systemic treatment options, and avoids the morbidity and mortality of major surgery. It is not a replacement for surgery, however, and should only be considered in consultation with your oncologist and interventional radiologist.
RFA is fast, easy, predictable, safe, and relatively inexpensive. Interventional radiologists work closely with oncology and surgical specialists to plan the best treatment for the cancer patient. Ask your physician about treatment options. Have your physician or oncologist call 919-781-1437 to set up a consultation with Dr. Satish Mathan or Dr. Jason Harris to see if you might benefit from treatment with thermal ablation.
Nothing to eat or drink after midnight. If you are on blood pressure medications, you may take your AM dose with a small sip of water, otherwise hold off on taking your other medications. Discontinue taking aspirin, coumadin, or plavix 5 days prior to procedure. Make sure a driver is available post procedure to take you home.