What are the possible causes of sarcomas? Scientists do not fully understand why some people develop sarcomas while the vast majority do not. However, by identifying common characteristics in groups with unusually high occurrence rates, researchers have been able to single out some factors that may play a role in causing sarcomas. Studies suggest that workers who are exposed to phenoxyacetic acid in herbicides and chlorophenols in wood preservatives may have an increased risk of developing sarcomas. An unusual percentage of patients with a rare blood vessel tumor, angiosarcoma of the liver, for example, have been exposed to vinyl chloride in their work. This substance is used in the manufacture of certain plastics. In the early 1900s, when scientists were just discovering the potential uses of radiation to treat disease, little was known about safe dosage levels and precise methods of delivery. At that time, radiation was used to treat a variety of noncancerous medical problems, including enlargement of the tonsils, adenoids, and thymus gland. Later, researchers found that high doses of radiation caused sarcomas in some patients. Because of this risk, radiation treatment for cancer is now planned to ensure that the maximum dosage of radiation is delivered to diseased tissue while surrounding healthy tissue is protected as much as possible. Studies have focused on genetic alterations that may lead to the development of sarcomas. Scientists have also found a small number of families in which more than one member in the same generation has developed sarcoma. There have also been reports of a few families in which relatives of children with sarcoma have developed other forms of cancer at an unusually high rate. Sarcomas in these family clusters, which represent a very small fraction of all cases, may be related to a rare inherited genetic alteration. However, in the vast majority of cases, sarcoma is a completely random event in a family’s cancer history. Certain inherited diseases are associated with an increased risk of developing soft tissue sarcomas. For example, people with Li-Fraumeni syndrome (associated with alterations in the p53 gene) or von Recklinghausen’s disease (also called neurofibromatosis, and associated with alterations in the NF1 gene) are at an increased risk of developing soft tissue sarcomas. How are sarcomas diagnosed? The only reliable way to determine whether a tumor is benign or malignant is through a surgical biopsy. Therefore, all soft tissue and bone lumps that persist or grow should be biopsied. During this procedure, a doctor makes an incision or uses a special needle to remove a sample of tumor tissue. A pathologist examines the tissue under a microscope. If cancer is present, the pathologist can usually determine the type of cancer and its grade. The grade of the tumor is determined by how abnormal the cancer cells appear when examined under a microscope. The grade predicts the probable growth rate of the tumor and its tendency to spread. Low-grade sarcomas, although cancerous, are unlikely to metastasize. High-grade sarcomas are more likely to spread to other parts of the body.
Posted on: Sun, 28 Jul 2013 01:19:24 +0000