Arterial embolization
Arterial embolization is a medical procedure that involves intentionally blocking an artery to deprive tumors of their blood supply, oxygen, and nutrients. This technique is particularly useful for treating various cancers, including hepatocellular carcinoma, kidney cancer, and neuroendocrine tumors, especially in advanced stages where surgical options are limited. The procedure often targets the hepatic artery, leveraging the liver's dual blood supply from the hepatic artery and portal vein.
During embolization, occluding agents, such as polyvinyl alcohol beads, are introduced via an angiographic catheter to block the artery, which can be combined with chemotherapy to enhance treatment effects. This method, referred to as transarterial chemoembolization (TACE), allows for localized drug delivery and can reduce side effects associated with systemic chemotherapy. After the procedure, patients typically require a short hospital stay and are advised to rest to facilitate recovery. Although risks such as total liver failure and "embolization syndrome" exist, many studies indicate that arterial embolization may improve survival rates in liver cancer patients. Additionally, this versatile procedure is employed to treat other medical conditions, including vascular malformations and uterine fibroids.
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Arterial embolization
ALSO KNOWN AS: Transarterial bland embolization, transarterial chemotherapy, transarterial chemo embolization (TACE)
DEFINITION: Arterial embolization is the intentional blockage of an artery, thus depriving a tumor of a blood supply, oxygen, and nutrients. In some cases, embolization is used to deliver drugs or other chemotherapeutic agents via blood vessels to induce the cytotoxicity of tumors.
Cancers treated: Hepatocellular carcinoma, tongue carcinoma, kidney cancer, liver cancer, neuroendocrine tumors
Why performed: In patients whose cancer is significantly advanced and for whom surgical options cannot be considered, or in conditions of metastasis outside the liver and inadequate reserves, arterial embolization is preferred as a viable alternative. This option is generally chosen when the tumor is greater than 4 centimeters in size, and there are multiple lesions. Arterial embolization takes advantage of the fact that the liver receives its blood supply from two main sources, the hepatic artery and hepatic portal vein, and that the major supplier of blood to the liver is the hepatic artery. During the embolization procedure, the hepatic artery is blocked. Embolization may be combined with chemotherapy or radiotherapy to enhance the effects of treatments.
Patient preparation: Patients are briefed on all the steps and options involved in the procedure. A hospital stay is generally required. Patients receive intravenous sedation to cause numbness and to mitigate pain.
Steps of the procedure: During the procedure, an angiographic catheter is introduced in the branches of the hepatic artery. Usually, a dye is injected for contrast and to acquire images. The hepatic artery is then blocked with occluding agents such as polyvinyl alcohol beads, which are transported to terminal hepatic arteries and occlude the vessels. The liver can still be healthy and functional using a blood supply derived from the alternative route of portal veins. In cases where arterial embolization is combined with chemotherapy (as in transarterial chemo embolization, or TACE), an anticancer drug (such as doxorubicin) is injected through the catheter, and then the artery is blocked. Pressure is applied to prevent bleeding after the procedure is performed. Sometimes radiotherapy is combined with arterial embolization.
In the twenty-first century, advances in arterial embolization specific to liver cancers have been made, including novel techniques such as transarterial radioembolization. Additionally, drug-eluting beads can be filled with chemotherapy medications and injected directly into the liver’s arteries, more effectively delivering chemotherapy drugs in conjunction with the procedure. Administering chemotherapy in this way has been shown to reduce side effects. A similar process can be achieved using microspheres as well.
After the procedure: An overnight stay in the hospital may be required. Generally, patients are advised to take adequate rest and avoid strenuous activities for at least twenty-four hours. The procedure may be repeated every six to eight weeks.
Risks: Total liver failure, although not common, is a risk associated with this procedure. Side effects termed “embolization syndrome,” including nausea, abdominal pain, and mild fever, may ensue.
Results: Increasing evidence shows that this procedure increases survival rates in liver cancer patients. In cases where it is combined with chemotherapy, recovery is expedited due to increased and prolonged concentrations of drugs around tumors. Arterial embolization is not only used to treat cancers; the procedure is effective in treating other conditions, including vascular malformations, bleeding, fibroids, aneurysm, and prolonged menstrual bleeding.
Bibliography
Ahn, Samuel S. and Wesley S. Moore. Moore and Ahn Endovascular Surgery. 4th ed., Philadelphia: Elsevier, 2011.
Chabrot, Pascal, and Louis Boyer, eds. Embolization. London: Springer, 2014.
“Embolization Therapy for Liver Cancer.” American Cancer Society, 1 Apr. 2019, www.cancer.org/cancer/types/liver-cancer/treating/embolization-therapy.html. Accessed 24 June 2024.
Matson, M. B., and J. A. Goode. "Embolisation of Cancer: What Is the Evidence?" Cancer Imaging, vol. 4.2, 2004, pp. 133–41.
Niederhuber, John E., et al. Abeloff's Clinical Oncology. 5th ed., Philadelphia: Elsevier, 2014.
“Transarterial Chemoembolization (TACE) for Liver Cancer.” Canadian Cancer Society, Sept. 2019, cancer.ca/en/cancer-information/cancer-types/liver/treatment/transarterial-chemoembolization. Accessed 24 June 2024.
Wáng, Xiáng J., et al. "Transcatheter Embolization Therapy in Liver Cancer: An Update of Clinical Evidences." Chinese Journal of Cancer Research, vol. 27, no. 2, 2015, pp. 96-121, doi.org/10.3978/j.issn.1000-9604.2015.03.03. Accessed 24 June 2024.
Zhang, Jingjun, et al. "Discussing the Safety and Effectiveness of Transcatheter Arterial Embolization Combined with Intravenous Chemotherapy in Treating Locally Advanced Breast Cancer." Scientific Reports, vol. 14, no. 1, 2024, pp. 1-13, doi.org/10.1038/s41598-024-56642-w. Accessed 24 June 2024.