What is Angiosarcoma
Angiosarcoma is a malignant, rapidly growing, highly invasive variety of cancer. These tumors arise from the endothelial cells that line the walls of the blood or lymphatic vessels. All blood vessels and lymphatics are lined by endothelial cells; the layer being called the endothelium. The tumor begins as a growth of rapidly proliferating immature cells, but can quickly become cancerous and spread to many other systems. Like most forms of cancer, angiosarcoma is uncontrolled cell replication, but its relation to the circulatory system poses unique threats to the health of any individual.
Types of Angiosarcoma
Hemangiosarcoma is a blood-fed sarcoma; that is, blood vessels grow directly into the tumor and it is typically filled with blood. A frequent cause of death is the rupturing of this tumor, causing the victim to rapidly bleed to death. Any malignant condition that affects the blood is extremely dangerous, for it is quite easy for the cancerous cells to “mestastize,” or spread cancer to other, healthy systems. Because angiosarcoma affects blood vessels, this type of cancer often proves to be aggressive, difficult to treat, and recurs often.
Lymphangiosarcoma is an angiosarcoma in which the tumor cells originate from the endothelial cells of lymphatic vessels. The lymph system is responsible for the distribution of antibodies and disease-fighting agents throughout the body. Any time a cancer affects a system that is responsible for distributing chemicals throughout the body, such as blood or lymph, it can spread the mutated cancer cells throughout the body also.
Angiosarcomas may occur in any organ of the body, but are more frequently found in skin and soft tissue. They can originate in the liver, breast, spleen, bone or heart. Cutaneous angiosarcoma is the most common form of angiosarcoma. This disease primarily is located on the head and neck of elderly persons.
Causes of Angiosarcoma
Causes of most angiosarcomas are unknown. Hemangiosarcomas are commonly associated with toxic exposure to thorium dioxide (Thorotrast), vinyl chloride, and arsenic. Stewart-Treves syndrome is a form of hemangiosarcoma due to lymphedema, usually following mastectomy and radiotherapy for breast cancer. Exposure to vinyl chloride used in polymerization in the plastic industry can lead to angiosarcomas of liver and soft tissue. Though exposure to these pre-conditions or environmental toxins may have occurred thirty years ago, people can still develop these cancerous tumors.
All Angiosarcomas tend to be aggressive and are often multicentric. These tumors have a high local recurrence rate and metastasis because of their biologic properties and because they are often misdiagnosed, leading to a poor prognosis and a high mortality rate. These malignant vascular tumors are clinically aggressive and difficult to treat, usually not responding well to traditional treatments such as chemotherapy or radiation.
Researchers are exploring the evidence of mutations occurring on P53 (tumor suppressor gene) in cells of angiosarcomas of the liver. The p53 tumor suppressor and its surrounding molecules are now the focus of thousands of studies in laboratories around the world. These studies may one day lead to new treatments for this life-threatening cancer.