Cancer is a term used to describe a disease in which abnormal cells divide uncontrollably and are able to invade body tissues and organs. Sarcoma is a type of cancer that invades bones and connective tissue, as well as several other organs and tissues. Osteosarcoma is the most common type of bone cancer, and the sixth most common type of cancer in children. From 2003 to 2007, the average age for deaths related to bone and joint cancers in the United States was 58.
Primary Bone Cancer
Primary bone cancer, or cancer that starts in the bone rather than by the spread of cancer from another organ, is rare, according to MedlinePlus.com. Primary bone cancer accounts for only 1 percent of all cancers, about 2300 new cases are diagnosed in the United States every year, according to the National Cancer Institute.
Genetics
DNA carries the instructions for cell development, including when cells should divide and when they should die. Errors in DNA, inherited from a parent, can cause cells to divide too rapidly, or not die promptly -- these errors in DNA may cause normal cells to become cancerous, according to the American Cancer Society.
Most osteosarcomas arise because of unpredictable errors in the DNA of bone cell development, according to MayoClinic.com. Osteosarcoma begins growing in osteoblasts, the cells that make growing bones, which is why this cancer often affects young people experiencing a growth spurt. Teenage boys are more at risk of developing this primary bone cancer than are girls, and most cases of osteosarcoma involve the knees.
Secondary Bone Cancer
Bone cancer is usually caused by the spread, or metastasis, of primary cancers. This cancer will be named for the organ of origin, such as lung cancer, breast cancer, or prostate cancer.
Radiation
While the exact cause of primary bone cancer is not currently known, several factors increase the likelihood of developing primary bone cancers. Most cancers are not caused by defects inherited from a parent; the majority of bone cancers are caused by genetic mutations acquired over a lifetime. Mutation is sometimes caused by exposure to radiation or chemotherapy during the treatment of another disease. The risk of developing osteosarcoma, for example, is increased for those people who have undergone high-dose radiation therapy for another illness. Often, these mutations occur for no known reason.
