Ablation or Embolization Treatments for Pancreatic Neuroendocrine Tumor

Ablation or embolization can sometimes be used to help treat a pancreatic neuroendocrine tumor (NET) that has spread to other organs, especially the liver.

When are ablation and embolization used?

Ablation and embolization treatments are different ways of destroying tumors, rather than removing them with surgery. When pancreatic NETs have spread to other sites (for example, the liver), these treatments can often reduce tumor size and improve symptoms. Ablation and embolization can also help treat pancreatic NET that has not spread to other organs, and is not able to be surgically removed. These treatments are very unlikely to cure cancers on their own. They are more likely to be used to help prevent or relieve symptoms, and are often used along with other types of treatment.

Ablative treatments (ablation)

Ablation refers to treatments that destroy tumors, usually with extreme heat or cold. They are generally best for tumors no more than about 3 cm across.  There are different kinds of ablative treatments:

• Radiofrequency ablation (RFA) uses high-energy radio waves. A thin, needle-like probe is put through the skin and into the tumor. Placement of the probe is guided by an ultrasound or CT scan. The tip of the probe releases a high-frequency electric current which heats the tumor and destroys the cancer cells.
• Microwave thermotherapy is similar to RFA, except it uses microwaves to heat and destroy the cancer cells.
• Ethanol (alcohol) ablation (also known as percutaneous ethanol injection) kills the cancer cells by injecting concentrated alcohol directly into the tumor. This is usually done using a needle through the skin, guided by ultrasound or CT scans.
• Cryosurgery (also known as cryotherapy or cryoablation) destroys a tumor by freezing it with a thin metal probe. Using ultrasound, the probe is guided through the skin and into the tumor. Then very cold gasses are passed through the probe to freeze the tumor, killing the cancer cells. This method may be used to treat larger tumors than the other ablation techniques, but it sometimes requires general anesthesia (where you are asleep).

Side effects of ablation treatments

Possible side effects after ablation therapy include abdominal pain, infection, and bleeding inside the body. Serious complications are uncommon, but they are possible.

Embolization

During embolization, substances are injected into an artery to try to block the blood flow to cancer cells, causing them to die. This may be used for larger tumors (up to 5 cm across; almost 2 inches) in the liver.

There are 3 main types of embolization:

• Arterial embolization (also known as transarterial embolization or TAE) involves putting a catheter (a thin, flexible tube) into an artery through a small cut in the inner thigh and threading it up into the hepatic artery feeding the tumor. Blood flow is blocked (or reduced) by injecting materials to plug up that artery. Most of the healthy liver cells will not be affected because they get their blood supply from a different blood vessel, the portal vein.
• Chemoembolization (also known as transarterial chemoembolization or TACE) combines embolization with chemotherapy. Most often, this is done by using tiny beads that give off a chemotherapy drug during the embolization. TACE can also be done by giving chemotherapy through the catheter directly into the artery, then plugging up the artery.
• Radioembolization (also known as transarterial radioembolization or TARE) combines embolization with radiation therapy. This is done by injecting small beads,called microspheres that are tagged with a radioactive substance (yttrium-90) into the hepatic artery. The beads lodge in the blood vessels near the tumor, where they give off small amounts of radiation to the tumor site for several days. Since the radiation travels a very short distance, its effects are limited mainly to the tumor.

Side effects of embolization

Possible complications after embolization include abdominal pain, fever, nausea, infection, and blood clots in nearby blood vessels. Serious complications are not common, but they can happen.