Ablation and Embolization for Colorectal Cancer
When colorectal cancer has spread to other organs such as the liver, the metastases can sometimes be removed by surgery or destroyed by other techniques, such as ablation or embolization. This might help a person live longer.
Ablation and embolization can often be good options for people whose cancer can’t be cured with surgery or who can’t have surgery for other reasons. Typically, you will not need to stay in the hospital for these treatments.
Ablation refers to treatments that destroy tumors without removing them. These are most often used to treat cancer spread in the liver, but they can be used to treat tumors in other places.
Radiofrequency ablation (RFA) uses high-energy radio waves to kill tumors. A thin, needle-like probe is placed through the skin and into the tumor using CT or ultrasound guidance. An electric current is then run through the tip of the probe, releasing high-frequency radio waves that heat the tumor and destroy the cancer cells.
Ethanol (alcohol) ablation
In this procedure, also known as percutaneous ethanol injection (PEI), concentrated alcohol is injected directly into the tumor to kill cancer cells. This is usually done through the skin using a needle, which is guided by ultrasound or CT scans.
Cryosurgery destroys the tumor by freezing it with a thin metal probe. The probe is guided through the skin and into the tumor using ultrasound. Then very cold gasses are passed through the probe to freeze the tumor, killing the cancer cells. This method can treat larger tumors than the other ablation techniques, but it sometimes requires general anesthesia (you are in a deep sleep).
Side effects of ablation therapy
Possible side effects after ablation therapy include:
- Abdominal (belly) pain
- Bleeding into the chest cavity or abdomen
Serious complications are uncommon, but they are possible.
During an embolization procedure, substances are injected to try to block or reduce the blood flow to cancer cells in the liver.
The liver is unusual in that it has 2 blood supplies. Most normal liver cells get blood from branches of the portal vein, whereas cancer cells in the liver usually get their blood supply from branches of the hepatic artery. Blocking the branch of the hepatic artery feeding the tumor helps kill off the cancer cells, but it leaves most of the healthy liver cells unharmed.
Embolization can be used for tumors that are too large to be treated with ablation – usually larger than 5 cm (about 2 inches) across. It can also be used with ablation. Embolization does reduce some of the blood supply to the normal liver tissue, so it may not be a good option for patients with liver damage from diseases such as hepatitis or cirrhosis.
There are 3 main types of embolization procedures used to treat cancer in the liver:
In this procedure a catheter (a thin, flexible tube) is put into an artery through a small cut in the inner thigh and threaded up into the hepatic artery in the liver. A dye is usually injected into the blood at this time to help the doctor monitor the path of the catheter with special x-ray pictures. Once the catheter is in place, small particles are injected into the artery to plug it up. Arterial embolization is also called trans-arterial embolization (or TAE).
This treatment, also called trans-arterial chemoembolization (or TACE), combines embolization with chemotherapy. Most often, this is done by using tiny beads that give off a chemotherapy drug for the embolization. TACE can also be done by giving chemotherapy through the catheter directly into the artery, then plugging up the artery.
This treatment is a combination of embolization and radiation therapy. In the United States, this is done by injecting small beads (called microspheres) coated with radioactive yttrium-90 into the hepatic artery. Brand names for these beads include TheraSphere® and SIR-Spheres®. 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. The radiation travels a very short distance, so its effects are limited mainly to the tumor.
Side effects of embolization
Possible complications after embolization include:
- Belly (abdominal) pain
- Infection in the liver
- Gallbladder inflammation
- Blood clots in the main blood vessels of the liver
Because healthy liver tissue can be affected, there is a risk that liver function will get worse after embolization. This risk is higher if a large branch of the hepatic artery is used. Serious complications don’t happen often, but they are possible.
Last Medical Review: January 15, 2017 Last Revised: March 2, 2017