Chemoembolization - Cancer Treatment

Chemoembolization is a specific type of cancer treatment, often used to treat cancer of the liver and specifically, hepatocellular carcinoma. The term chemoembolization describes a procedure in which an “embolus” or bolus of chemotherapy is delivered directly to the tumor and blocks blood flow it. It is a way of administering a relatively high concentration of cancer-killing drug directly to the tumor itself while avoiding many of the systemic problems associated with chemotherapy.

 

Most chemotherapy is delivered through a large vein and circulates through the entire body—everywhere the blood vessels supply blood. The chemotherapy used in chemoembolization is delivered focally. A small cannula inserted into a groin blood vessel is “snaked” up through the circulatory system until it reaches the blood vessels supplying the liver. In fact, the specific blood vessels that supply the liver tumor can be identified and targeted. Once the cannula is in place, a bolus or small dose of chemotherapy is released and the blood carries it to the liver. While the overall dose of chemotherapy given during a chemoembolization is small in relation to what is administered in traditional chemotherapy, the dose that is taken up by the liver is relatively high. Most preparations of chemoembolization are in the form of microspheres. These microspheres adhere to the tumor cells and slowly release chemotherapeutic drugs in and around the tumor. The microspheres also block blood flow to the tumor and starve it of oxygen and nutrients. Since the chemotherapeutic drug is not diluted to any great degree by the blood, the concentration that is sent to the liver is much higher than it would be traditionally. Thus chemoembolization presents the tumor with a very high dose of tumor-killing medicine but spares the rest of the body many of the harmful side effects that occur from chemotherapy.

 

 

Chemoembolization may be performed by a number of different medical professionals but it is usually done by a physician called an interventional radiologist. This doctor, along with the cancer treating team of medical and radiation oncologists will coordinate care of the liver tumor and determine if chemoembolization is right for a given patient. Common conditions that may make chemoembolization inappropriate is a blockage of the portal vein (the main vein of the liver), moderate of severe cirrhosis of the liver, or a blockage or stenosis of the bile ducts. These conditions can be diagnosed from clinical examination, laboratory tests, and radiological studies.

 

Chemoembolization have been combined with other focal cancer treatments such as radiofrequency ablation. Since the chemoembolization cannula is very precisely guided to the tumor, it can be used to administer an energy that disrupts and destroys the tumor without disturbing the surrounding liver. These two intereventions, chemoembolization and radiofrequency ablation, are very powerful techniques for fighting tumors and preserving organ function at the same time reducing or avoiding adverse side effects.

 

Liver cancer has been the primary type of cancer treated by chemoembolization. This may mean primary tumors of the liver or tumors that have spread from other organs and seeded in the liver. Trials are underway to apply the same chemoembolization to other solid tumors with high degrees of vascularization (blood vessels supplying it). Lung and kidney cancers are possible applications for chemoembolization in the near future.